Why You Need To Stop Using These Filters To Purify Your Air! What To Use Instead
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- Опубліковано 5 кві 2024
- In this video, I talk about how you may be doing damage to your AC by using those expensive filters that are rated to remove pollen, smoke, and much more out of your air. I will also talk about what you should be using instead.
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I'm curious, have you been using these filters or used them in the past?
Yes. Depending on whatever is cheaper but 2500or 2800.
Filtrete = Concrete, saw this on an HVAC forum.
Pros all recommend the plain cheap ones.
Yes I get them at Home Depot and they seem to work well.
Only once: it was a MERV 13 filter and I installed just at the beginning of winter. It did filter the air more effectively, but it wasn't worth the cost of the filter or the higher gas bill.
Your gas bill will not be higher if you install an air filter. Electricity use might be if it gets very plugged. Even If you don’t mind dust and pet hair or dander, you at least need a filter to keep your AC A-frame heat exchanger clean. If you do not keep it clean, your AC will run constantly and it’s very expensive to get them cleaned. I’ve seen AC A-frames they have so much lint and pet hair on their surfaces that no air at all was going through. It looked like grey fabric was on the surface. The homeowner forgot to replace the filter for a year.
My father had a excellent solution. Instead of putting the filter at the HVAC unit, he put smaller filters at all the intake points. More filters equals greater filter surface area, and the ductwork is kept clean since the air is filtered before it enters the ducts. He did this when he built their house back in 1986.
Smart dad
Sadly, not many things are designed with maintenance or longevity in mind anymore.
I would argue that HVAC designers need to stop designing return air ducts and grilles to the minimum size for a given airflow. A modest increase in duct and grille size would allow enough airflow with a premium filter to avoid this issue. When I did my own system many years ago, the pro I brought in to charge the A/C was impressed and pointed out the oversized return. I told him I did it on purpose to allow for better filters. The total extra cost of the oversized grille and short duct run? Around $50.
Static pressure is a big player in HVAC design. Im not an expert in ductwork or static pressure but i do know that tampering with it can cause problems with its ability to cool and heat. Plus, bigger coils have show a significant issue with dehumidification as well as short cycling.
Another big thing you need to know. While hvac companies have people who design the ductwork, often times the BUILDER has the final say. Alot of bad filter slots and designs are attributed to the builder saying what happens at the end
told that same duct size goes in and out or bigger return . like 12" round in and 12" round out. something 'about energy efficiency
return too small a system must work harder. that's why they have damper in return airi
it re-approve by the engineer
The issue is not just the return system, the issue is that the entire system is designed for a desired flow rate. If you reduce the flow through the system beyond design parameters, you will alter cycle times which can negatively affect both heating and cooling. Yes, it would be nice if the manufacturers of the equipment and the designers of the overall duct systems would base their designs on a better filter. Until they do, I strongly suggest you don't exceed a MERV 11 filter. If you want the air in your rooms to be cleaner than what a MERV 11 can do, get a properly sized whole house electrostatic air cleaner added to your system.
define oversized return?? I'm curious... Thanks!
@@biz4twobiz463 If you need me to define it, then you obvoiusly don't know how to properly size ductwork.
I custom built a pre-filter box for my whole house air filtration system. The box has a series of six slots with six inches between each slot and twelve inches between the opening and first slot as well as the sixth slot and the exhaust which goes into the actual system for a total of ~65". I also use a UVC lights at the beginning and end.
I use 24x24" filters in the following order:
Electrostatic metal washable
MPR (MERV) 300 (5)
MPR (MERV) 600 (7)
MPR (MERV) 800 (10)
MPR (MERV) 1200 (11) carbon
MPR (MERV) 1500 (12)
System filter:
MPR (MERV) 1900 (13)
I clean the metal electrostatic weekly or better. The rest get replaced 1-12 months. My system has an airflow monitor and has only gone off twice after wildfires. Note that it cost me about $75 to make the pre-filter box and has saved me dozens of times more in expensive filter costs and maintenance as the system and downflow ducts remain very clean.
Yes, I did go overboard but enjoyed the process and final results.
You and my youngest son think alike. He redesigned his HVAC system and runs a schedule for spring allergies and autumn dust. He also added an ion machine to precipitate dust.
I've had many a AC tech call the low MERV rating "rock stoppers", because that's all they will stop!
When our HVAC guy did our house he sized the system for 20”x25”x5” MERV 11. Our house doesn’t get dusty and it has helped with mild seasonal allergies. We also installed an air sanitizing UV system. No regrets.
Which system did you purchase? 1:23
@@moniqueheubel8970 I’m not sure what you mean by system. Our filter box is Air Bear, the UV device is a BioShield72.
@@joeyoungs8426that’s a good system.
My AC Contractor who installed a new TRANE Furnace and AC system in our house suggested no higher than MERV 9 for the filters. If you watch other Air conditioning vidoes, they point out if the MERV is too high, blocking the intended air flow form the Blower, you can create harmful Air Pressure which can damage your unit and shortedn the life.
Moved here 2 years ago, air system filter is MERV 11 , 15" X 25" X 5" . It worked well cleaning smoke when forest fires were in full fury.
I watched another video "Furnace filter-which furnace filter is best". The tested a wide range of filters using a manometer. He found that the 3M filters were quite impressive for the low pressure drop across the filter. We have been getting a lot of fire smoke here in Alberta. I installed a thicker filter box to use 25X20X5 filters. I installed a Merv 11 and use it with 2 Honeywell extra large room Hepa Air Purifiers with good results. Keep in mind that a lot of house hold dust will settle out before it makes it into your return air to be filtered so don't think you can throw away your Swiffer any time soon!
What does he say at the end of the video though? That one controlled test he did is not the gospel truth. Which is why I believe he says what he does at the end of his video. Also I have nothing against Filtrete fillers. They are some of the most popular for a reason. My issue is the MERV rating regardless of brand.
@@HowToHomeDIY 3M filter myth busting Video. Video is from 3M so many would call it fake news. I personally believe in filter media R&D
Now have them do one when the filters have been in the unit a week. Because they catch more things, they fill quicker and efficiency is not going to be nearly as good. I will trust the guys that have all told me the same thing that work on and replace parts on numerous acs due to the higher efficiency filters.
23 years doing HVAC installer, tin knocker, service tech, service manager, and instructor working in residential, light commercial, and commercial work. I pretty much agree with this whole video. The only thing that makes it hard to say this is the filter that you should go with or not because everybody’s duct system is different, and also depending on equipment, registers, and zoning it makes it really difficult just to say this is what you need to go with and you’ll be good. So my recommendation is if someone only had a 1” filter slot they could get a couple different filters and have a reputable company come out and check total static pressure while changing of each and then make your determination after you actually measure instead of guess. It is always better to have a media cabinet 4”+ filter you will be able to have much more surface area and be able to have a higher efficiency filter at a lower total static pressure. FYI MERV 16 is equivalent HEPA efficiency. Hope this helps!
So is this discussion only about 1-inch filters and not about 4-inch filters?
@@kirkdarling4120 I was just referring to more the 1” filter more so due to that’s what the video was referring, I just threw in my two cents about the 4” filter.
So listen, if you're going to have a 4" HEPA filter, you absolutely better have designed your HVAC with that in mind.... but if you added something like this to most home systems they are not designed for anything remotely that restrictive.... and it's not that the system can't run with it... it's definitely adding a load that wasn't designed for... but it's when people forget to change them or clean them religiously and the filter gets dirty... then it can restrict a ton of air which will burn your compressor out in a hot min haha
@@mikeschmid5133 Why burn the compressor out? Just curious.
@@DevonWildZillaTeschJrnot sure either. The compressor is outside the house. Maybe he meant the air handler motor?
I ran Filtrete 1500 on my 20-year-old furnace, in a 2500 sq ft house, for 12 years and never had a problem. I did have to replace the blower motor once, a temperature sensor, and an exhaust fan motor. But it is a very old furnace. We replaced the filter every 3 to 6 months and kept the fan on continuous.
never had a problem with my systems and as an asthmatic wholeheartedly will say there is nothing better than a high end 3M to ease your breathing and deal with allergens. Happy user since the mid 80’s. 1500 minimum, which captures cooking odors and smoke as well.
if you want to keep the large particles from clogging the better filters, sandwich one of their basic (blue mesh washable) filters ahead of it to catch those and change that one out or wash it when you see it load up, the carpet of dust that forms is what helps reduce service life of the better filter.
My daughter has really bad allergies, and is an asthmatic. I’ve used good quality filters for years and it has helped her out a lot. We also have standalone HEPA filters in the bedrooms. Without all of this, we end up making several trips to the emergency room every year.
I will take the chance of wearing out parts on my HVAC system as a side effect of keeping my daughter healthy.
I understand the concern about a filter restricting the flow. But the filtering efficiency is not the only factor to consider when trying to determine how much the airflow is restricted. It also depends on the material, how thick the filter is, how large the filter is, and the amount of area created by folding. First there needs to be some measurements taken of the airflow restriction caused by these filters. Second, we need some determination of how airflow restriction affects the unit's efficiency and reduces it's life span. The problem is more complex than just picking a MERV number.
I had the furnace and the AC serviced last year and I asked about the filters I should use. The answer was to avoid both the cheapest filters and anything higher than MERV 8. So, pretty much in line with what you're recommending.
I was using a MERV 12 and our HVAC guy stated not to go over an 8 as well.
Good to hear many people parrot the same thing from their HVAC guy.
I said MERV 5-8 is recommended. I use a 6.
Did you actually talk to an engineer who designed your system? No.
@@Slick1020 out of curiosity, who are you asking that question of? I don’t know, as you cannot tell from YT’s comment system. Do you actually think the average home HVAC system was designed by an degreed engineer? The one in my home, was field installed and like most custom homes was a one-off job following general rules of thumb. They follow the Furnace and AC manufacturers guidelines, if they even took the time to read them. And as a professional degreed engineer myself that talks to many engineers a day, I don’t offer recommendations outside my field of disciplinary expertise.
@davidsamsonite5791 you are saying things I did not say, taking things out of context, and twisting what was said and clearly meant. I’m not going to get into a big back and forth with you on my intent and what I actually said when it’s very clear and what you are saying is not what I said or a twisted version of it.
Have you or any of your readers noticed that lately (some) filter manufacturers are making their filters ¼ inch smaller than the posted size on the wrapper? This is causing extra air noise inside the house coming from the filter cage in the ceiling. What is causing this because I do not agree with selling us consumers short. The the way - great video and I absolutely love your channel as you have helped me maintain my home much better and have saved me considerable money.
I noticed that about the Home Depot HDX filters - instead of 1 inch thick filters, they give you a 0.8" thick filter. Multiply 0.2" x 2 x the number of pleats is much much material they saved. So now I just stick with Filtrete and buy them in bulk whenever they're on sale.
Didn't scroll through all the comments but every quality filter should have its airflow ratings printed on it or the packaging somewhere. Your HVAC system has ratings that it was designed for. You should be able to match them up. Issues arise when the entire system (furnace, AC, ducts & filter) is not in harmony. Our old house was an example of this. Not enough intake air in original ducts and the AC was running too a high a fan speed that made for short runs and the humidity remained high. This also stressed the filter. Corrected these issues and was able to maintain correct air flow with MERV 11 filter. It is always a sum of all the parts in play.
When we had our new furnace installed, the HVAC contractor put in a 2 inch filter holder, and increased the furnace intake area. Made a big difference in home comfort and the furnace handles a MERV 8 no problem.
I’ve ran 4” thick MERV11 filters in my system for years with zero issues. I change them every 60 days even though they’re completely clean (what human eyes can see anyway). Yes, the air is dry and cold in my house but my German Shepherd greatly appreciates it.
From what I've seen, particulate filters for air "expire" by getting clogged, not by leaking. Use them until air stops moving through them quickly enough, they should actually clean the air that does go through at end of service life better than when they were new.
Charcoal filters start leaking mostly high vapor pressure substances (and with mixtures this can actually result in the filter's output air having a higher concentration of one chemical than the inpur), experience migration when in storage, are difficult to check the saturation of without knowing what's in them or doing $100+ tests, and otherwise have issues that make conservative replacement common when it's really important.
Consider getting a manometer, it's just a differential pressure guage with tubes, sensitive enough to measure the pressure drop across a filter. They sell them as portable units and parts you can install on your system. When the pressure drop gets too high (depends on your system, ask an HVAC tech) the filter needs to be replaced.
@@reddragonflyxx657This is the only way to know when a filter really needs to be changed. I don’t know why makers don’t do it from the factory. Time based is just guessing. Although I look at mine to see how dirty it is.
I was thinking about installing a gauge on my air handler. There are a couple ways of doing it. Problem that I would have is knowing what reading I would use to know when the filter needs to be changed.
Please note that the MERV 12 has more folds than the MERV 6. Therefore, the MERV 12 has a larger area for air to pass and thereby counteracting the effects of the thicker material.
makes since
Logic tells me that they are closer together, therefore maybe making it harder for the air to pass through, the max area that can allow air is the filter size, putting more folds to me makes them less good for air flow. But better for filtration. Maybe I am wrong, but a filter WITHOUT folds would allow the least restrictive air flow.
@@jimbo6134that's not how air works, increasing the surface area allows more air through. If that were true all air filters would be flat
They also use better material that captures particles more efficiently. 3M merv 13 actually has a lower pressure drop than their merv 8 and 12, and seems to keep that low restriction as it gets used up.
If you think about it, we have N95 masks that don't require super suction to breathe, yet they capture 95% of particles sized 0.1 micron, anything smaller or larger is captured at a higher efficiency than 95%. Our furnace filters actually have this same efficiency curve, higher end filters utilize smarter methods of capture like N95 does, diffusion, impaction, interception. Diffusion is what gets the finer particles, and when set up right it doesn't restrict much. Capturing ultra fine particles with impaction by having some ultra tight filter material weave would be incredibly inefficient.
And the 3m 1900 merv 13 has one of the lowest pressure drops.
You are absolutely right! I got my Dad a similar filter for his furnace and we couldn't get his house heated up like usual, when using a cheaper filter. We were also told that it can damage his furnace.
My local HVAC company educates customers just as you have in this video. I've been using the 3M Dust Reduction Level 300. MERV rating not on package as you stated. It is located on the filter itself. Back side on the bottom reads MERV level 5. Thanks for all you do for us!
My AC guys (I’ve been using for 23 years) told me max merv rating of 8…no higher because it’s too much stress on my system. They’ve never steered me wrong yet. Thank you for saving us money AND our systems with your valuable info!
*I change mine every 30days - the day I write the check to the electric company. Easy to remember that way. Thanks again! ♥
Every 30 days????
@@Soljarag5 Yes…every 30 days…makes it very easy to remember to change the filter: write the check to electric company - change the filter. Understand, I live in Florida…my AC runs nearly 24/7. During the winter months the filter isn’t in terrible shape, but I still change it. But in May thru October it gets filthy because it’s running nonstop. I buy a case of the filters at Home Depot - cheaper that way and my AC is happy for the clean filter 😃
@lizzieb6311 absolutely same thing. I also live in florida. Every 30 days, I also clear my drain lines every 90 days.
@@gogators5762 Yes! The drain lines….so important here with our ac running non stop…what a slimy mess! Haha…hey, Gator fan here too! Chomp Chomp!! 🐊
@@lizzieb6311Maybe get a manometer and test if it's still in tolerance for your system every 30 days.
Good point to not rely on the HVAC to clean your air.
I buy the filter that the project farm guy recommends. His testing showed the higher pleat count didn’t restrict airflow as much as the low pleat count did, which is what we’re trying to avoid here.
Higher pleat count implies more surface area, yes?
I would rather use air purifiers.
Project farm is awesome
One more thought about "higher pleat count is better": I think that comparison refers to filters that have the same (or similar) MERV rating. The same MERV rating can be achieved with fewer pleats (less surface area) but that requires greater thickness and/or greater density. Less surface area is more restrictive against flow, and so are greater thickness and/or greater density, so fewer pleats is a loser in two ways when comparing filters with the same MERV rating.
If you're comparing filters with different MERV ratings, the effect on air flow of the thickness & density of the filter material may be more significant than the pleat count. For example, the MERV=1 filter shown in the video has zero pleats, yet it has better air flow than high-MERV pleated filters because its filter material is thinner and less dense.
The effect of _deeper_ pleats ought to be like having _more_ pleats, because that too would increase total surface area. But there's a practical limit on depth since the filter must fit in a narrow slot in the HVAC intake duct. (The narrowness of the slot is also what limits the thickness of the filter, of course.)
A DIYer who isn't concerned with aesthetics might consider constructing a large filter-holding frame at the inlet of the HVAC's return air duct, and either leave the original slot empty or put a MERV=1 filter in the original slot. The custom frame could be very large so a filter with much more surface area (and thickness) could be used. An array of high-MERV filters, taped together side-by-side, would have a huge total surface area to maximize air flow. A large filter (or a large array of filters) will also last longer than a smaller filter because the captured particles would be distributed over its larger surface & larger volume.
A clever DIYer could also add a one-way "valve" -- a gate on a hinge -- to the frame, which opens only when the HVAC fan is moving air, to eliminate backdraft. (Gravity could close the gate. If the gate is lightweight and the hinge has little friction, the HVAC suction would be stronger than the effect of gravity and would open the gate.) The anti-backdraft valve would help when the HVAC unit is located outside or in an unconditioned room/closet, and the unconditioned air around the intake duct makes the duct cold in winter or hot in summer. (Wrapping the duct with thermal insulation is a good idea too.)
@@brothermine2292 that is partially true. It is correct, the same material, same pleat counts but higher MERV would create more restriction, but project farm showed that higher pleats with higher MERV can reduce air flow. Possible due to changes in materials, maybe the fuzziness 3M has to their higher end filters.
I use a merv 16 filter in my HVAC. 20x20x5 size. The actual pressure drop measured is lower than the merv 8 filters i was given and hasn't changed more than 0.01 wc at 650cfm after 8 months. The rated pressure drop is just 0.10 wc at 650cfm at 0.25 wc at 1400 cfm.
By far the biggest factor to filter restriction is the quality of it. Buy yourself a cheap merv 6 from filterbuy and you'll have more restriction than a well known brand like Honeywell or 3M merv 13. Do some testing yourself or look up some independent testing to confirm.
Merv 13 3m 1900 has one of the lowest pressure drops out there.
Working HVAC I replaced a filter that was so plugged it almost was sucked into the return air vent. I could hear it whistling upon entering the front door. I pulled it then checked the system to verify it was the only filter. Told the homeowner that it was the filter and I could find nothing else wrong. It was less than a month and I had the same call, same problem. Had to explain that when a filter was plugged no matter the time in place it needed to be replaced. They had just moved in. I think it was the sprinkle carpet deodorant that was popular at the time that put a lot of powder in the air when vacuumed. I think it was a heat pump unit.
I'm local to a supplier Airstar in Boca Raton and he ships. I have his filter frames. He sells the filter material that goes in the frames. I change both filters (2 units) every month. I buy a years worth of filters at a time. It comes out to a good cost savings once you have the frames. I had an ECM blower motor go out after 1.5 years. These don't like static pressure (restriction) This is a 4 year old house now. This is also before I started using these filters. I was using those high merv ones previously. I have since cut panels in my A/C closet doors and installed custom louvers for more return air. The builders A/C company wanted $700 labor to install the warranty blower motor. I bought an ECM rescue motor for $300 and installed it myself. I also installed UV lights in both units.
a very timely video! I live in New Mexico. In the desert! it doesn't matter what filter i buy i can't seem to knock the dust down that gets in the house. This has pointed me in a better direction!
sounds like a MERV5 or MERV7 is best for NM, based on this video.
@@biz4twobiz463 i ordered some merv 8 last week after seeing your video. they are all cheap enough that i can try different ones. the ones i had been buying were merv 13 and i did notice that when changing them every month they were so full of dust and lint that it would be surprising it the heat-a/c unit was breathing at all.
Your home may not be seald and your are pulling in dirt from other places. A smoke test will show you if you have leaks.
We have a 2000sqft house. I have 3 return vents to the AC/Heater (two 20x20x1" and one 12x12x1). I use MERV8 1" thick on all the return vents and change them every 4 months. They do such a great job that when I change them the filters are obviously dirty. I also lined the return vert housing's so the filters seat with an air-tight seal around their edges - otherwise the dirty air will get pulled into the system around the gaps on the edges of the filter. With a total of 1000sqin of airflow into the blower, it is more than enough airflow to keep the blower from burning out.
I built a simple air purifier using a 20" box fan and five 24"x24"x4" MERV13 filters taped together to form a cube that is taped to the back of the box fan. The MERV13 filters are rated to remove crap down to the bacteria level. Five MERV13 4" thick filters allow for almost unrestricted airflow through the box fan and can recycle a bedroom's worth of air in a few minutes. I built it during the COVID lockdown, but I keep using them. It's about $10 per filter on Amazon.
Neat idea
Those DIY air filters are far better performing than the most expensive air purifier you can buy, HEPA purifiers just don't move much air or they're a jet turbine. Using a merv 13 filter and a fan and your moving so much more air to actually get filtered, and you're actually able to filter the rooms air volume constantly.
Yes I have the same stuff. I stock-up on the filters whenever Costco/samsclub has it on sale. Gets rid of bacon smell too when cooking.
We had to call the pro because our central heater was stopping before the set temperature. He recommended us to use a thinner filter than what we were using. Thank you for sharing this info with the community.
A pro who didn't design the system. Right...
Mine too! He told me max Merv rating of 8 and change every 30days. I change it every time I write the monthly check to the electric company…makes it easy to remember
I was told to buy in bulk cheaper filters because you can change monthly and it's cheaper!
@@NYtalk60 Yes it’s true…mine net out to about 5.60 per filter when I buy them by the case…every 30 days I change them and my AC is happier for it 😉
Lived in Asia for a short time and had two air filter machines in our apartment. Was a shock each month to see how bad our air tuned the filters black every 30-days
I too once installed a higher rating filter which was restricting air flow, and when the unit shut-off, I was able to hear the metal pop as it deflated. I now use an FPR #5 rating, works well and there is no decompression sound after it shuts-off.
I use Merv 4.But I have two house filters the same you use,that run on low but have sencers to up the fan speed.Great video.Never a problem with the furnace.Plus the house cools and warms up quicker.
I've been using these filters for years. I write the "Change On" date on the filter which usually coincides when my Nest says "Time to replace your filter". I recommended this filter to a friend for her allergies, she can now sleep at night. Just make sure you change them accordingly, if you've been "renovating" or doing anything that produces a lot of dust / air borne debris, change your filter. I've changed a one month old filter once they finished putting in our windows.
i think the high number of pleats on the Filtrete 1500 and up increase the surface area substantially to make up for the restriction they would otherwise have. In most cases the Filtrete 1900 filters flow more than many Merv 8 filters from other brands. I don't believe the Filtrete filters suffer from restrictive flow issues. However, they do clog up faster and should be replaced every 30 days. On the other hand, there are other companies that make Merv 10 through 13 filters that DO NOT increase the pleat count, and thus are terrible for the air handler from the beginning.... Filterete is the only company I know of that increases the pleats on their 1 inch thick filters.
At work, our units have to circulate a lot of air and the pleats are four inches deep. The air filters are sort of intimidating to look at. One thing I notice is that all the good air filters have metal mesh to resist filter collapse from overpressure if it gets clogged up from not being changed often enough.
During wilfire smoke season, my family runs a box fan pulling air through one of those 20"x25" HVAC filters to clean our indoor air. It works great, since you can run the fan 24/7. The same box fan has been working for years. We also have an air purifier similar to the one from your links, I like having the air quality display.
Have you experimented on dirty air days to see how much sooner the air is clean as indicated by your unit with the display? That is, on a dirty air day, after allowing dirty air to enter the residence, for Test #1, run just the clean air unit and see how long it takes for the display to show a certain "clean air" level has been reached. For Test #2, run both the clean air unit AND the box fan plus its MERV 12 to 14 filter and see how long it takes for the display to show the same "clean air" level as in Test #1. For Test #3, you'd run the MERV 12 to 14 filter with the box fan by itself. Every now and then you'd turn on the unit with the display indicator to measure the "clean air" level. When the same "clean air" level has been reached of Test #1, then you can get an idea of how effective box fan plus filter works based upon the time difference.
@@animejanai4657 that sounds like a good way to quantify the exact difference. When the air was smoky outside, I was less interested in precise measurements and more interested in getting the indoor air as clean as I could get it. The box fan got turned on and left on. I may try to do some testing like you've mentioned the next time the air is smoky.
This video could not be more spot on. Another tip is don't waste money on brand name filters for your air handler, like Honeywell. There are aftermarket filters that are every bit as good, and they are MUCH less expensive, especially if you buy them by the case.
Not all filters are the same. One brands merv 8 filter can be significantly lower restriction than another, it's not a restriction rating as material quality makes a huge difference. If they don't have testing data for initial airflow resistance you should not buy it!
Generally the cheap filters are noticably restrictive, like filterbuy, compared to something like 3M or Honeywell Merv 13. I can give an example as well, the merv 8 filters that were white label branded by the HVAC company I used tested about the same to slightly worse than Honeywell branded merv 13 filters I bought, both the same dimensions. A merv 16 filter from Lennox that was 1 inch thicker tested lower than all of them and after 8 months of 24/7 blower circulation it's not really increased much.
Filtrete filters are electrostatically charged depth filters. Unlike a conventional pleated filter that catches particulate on the surface and blocks air flow paths, the Filtrete is a woven web of charged material that grabs particulate. Air continues to move through a low pressure path through the depth of the filter material. That's why it can catch more particulate and still retain an acceptable pressure drop. I've worked with 3M on these in the past in commercial air handlers with continuous pressure drop monitoring. They cost more, but they catch more particulate and last longer.
For crafty home owners I would recommend getting a low-cost static pressure tester + pitot tubes and then test the air handler/furnace (plenty of videos on UA-cam). If the supply and return ducting (if any) are designed/built correctly and static pressure is within norm for the unit (check the manual, there should be a chart, but in general all residential units should be under 1.0inWC, usually around 0.3-0.5) after installing new filter, then monitor the pressure and occasionally test how much restriction is happening as filter gets filled with particles.
There is no point in changing filter(s) early if it is not causing a restriction. This would be the best compromise, that way one knows how often to change filters and also can get away with using filters that trap more contaminants. Too restrictive is bad but a sieve that lets practically everything through is no good either. Even if higher MERV filters with more surface area/pleats can flow better than lower MERV non-pleated. Ideal would be the pleated/accordion style in 3-5" high filter in a cabinet, these last for 6 months in most cases easily.
I upgraded from MERV 11 to 13 once, and I could hear the difference and see the filter bowed by the force of the air being pulled thru it. I now have 3 air purifiers around the house and the HVAC filter doesn't get dirty nearly as fast, so when I run thru my current stock of MERV11 filters, I'll drop to 6 & see how that that goes. The only problem I've seen with the purifiers is that they get noisier over the years. Now, I run the bedroom filter during the day and the living room & study filters at night, when I'm not in the room.
I’ve used 3M filters for decades with great results and no problems. Airflow is excellent with minimal pressure differential.
I had a HVAC guy tell me once to buy the cheapest filters and change them often. I check them and change when they get dusty - probably every month or so.
I only use Camfil/Farr aeroplete filters.They are the best,no question! Been an HVAC tech for 30 years,and I have used them all and there is no comparison,Merv 8!
Where do you buy them at?
From Camfil USA local branch,
Smart man. Good advice.
The facts are that the pressure drop curves vs face velocity (or air flow for a given size) are published for all of these filters. So, you can look up the information and what you find is that there are high merv filters that don't have a particularly high - or excessive - pressure drop. So, those can be used in an HVAC system. As long as you keep your system static pressure drop within the limits of your air handler manufacturer, your system should work just fine.
You can't simply make blanket statements and say a high Merv filter is bad and restrictive. It might be, it might not be any more restrictive and might actually be better than a lower Merv filter. It depends of the surface area of filter media and the specific filter technology (electrostatic tweaks to the media). Why don't you get a digital monometer and do the actual measurements for the filters instead of creating a advertisement for room air filters.
Blah blah blah. Yeah that helps but it’s still restricting the air more than a MERV 5 or 6 but quite a bit more and when it starts getting dirty it’s way worse.
Someone who gets it! The real issue is with the HVAC industry. They use too many rules of thumb. There needs to be a gauge that measures the pressure drop and signals when the filter is too restrictive for the air handler. Why aren't skilled HVAC techs recommending an actual solution? Is it because they weren't trained or didn't investigate? Imagine if vehicles didn't come with a gas gauge. Mechanic "just put in 20 gallons every 3 days". That statement is meant to make the reader think a little. Yes, on a long trip you'll run out, other days you will overflow the tank (waste). FYI. Dwyer sells a differential pressure gauge for ~ $100. Every house is different, the frequency of filter changes will vary seasonally. An HVAC system can be designed to clean the air. Regarding the proposed solution of separate air cleaners: it increases user maintenance. Check the air cleaners' web site. 3 different filters, 3 different change intervals. Average homeowners don't change 1 filter regularly. P.S. This is meant to help educate. The video is helpful for those who don't want to go deeper.
this is good information cause I have used these in the past. I will be switching next season thanks so much 😊
You are very welcome! I remember when it was pointed out to me years ago by an AC tech and it was like my eyes were opened to what I was doing haha. Thanks for the feedback!
I have 2 Levoit Core 400 units. I really like the PM 2.5 monitor. It doesn't always keep up when cooking though.
My AC guy installed an Aprilaire media filter on my system -- its a MERV13 but designed for a much longer life due to how much area it uses to filter. They run about $50 a filter, but only need to be changed annually.
Thank you for sharing! This has been my thoughts with these super thick filters and we found the old school basic filters with the silver circles and also have a Honeywell filter in the attic that requires replacement every six months but we replace it every 4.
QUESTION: Do you have to keep buying hepa filters for that air purifier if so how often and how much? 🤔
I've been using those green EZ flow filters in my house since it was new 9 years ago in both units. Never had a single issue with the AC.
I had to use Merv 1 filters in a previous condo unit because the way the condensation line was run and higher rated filters didn't bend easily to install.
Project Farm did a pretty comprehensive test of these types of filters. I ended out changing the one I use because of it.
PF…the best!
Project Farm basically showed that MERV 11 was the beginning of the quality filtering of the tiny particles. The MERV 8 was basically for dust particles and large floating things and let a lot of the small particles through.
As for when to swap out your central air filter, it depends on how dirty your household air is. If it is full of greasy air and tiny dust, then you'll need to swap filters out. I run both HEPA and MERV14 air purifiers inside the house, so the central air filter lasts much longer as the amount of dust and pollen in the air is already greatly reduced. I have quality exterior exhaust for the kitchen air plus I never deep fry, so I don't particularly have greasy air mixed with dust that clogs up the central air filter.
@@animejanai4657 yes, airborne grease kills filters very fast. If you have a gas stove and do not have a powerful exhaust hood, you will find sticky oily crap collects on every surface within 3 meters. Exhaust hoods should go directly outside and should have a washable metal filter in them.
Oh it must be the gospel truth then 😂
Thanks heading over to see his video now! Love that guy.
W changed from merv 5 to merv 3 to make it more easier on our air handlers. And we figured out how to make our own filters because many of them are custom size.
An hvac filter protects the unit; a separate WHOLE house filtration system protects the occupants. I built & installed a diy 24"×24" size, prefilter, hepa & Uv genocidal lamp (254nm). Return air, one end of house, discharge opposite end; separate from main ductwork. Used a German bb blower, 24vdc, solar powered; runs 24hrs@day. Main furnace filter (also 24×24") lasted five years. Protect eyes from UV light.
Ed c
A UV genocidal lamp? or germicidal? 😅 It makes a difference!
Absolute truth. I used to get the real expensive filters and they burned out my motor which was expensive. I do merv 7 now…. Can’t find the 6 anymore
Nah I hate to say it, I been in commercial HVAC local 19 for 20+ years and this dude is 100% correct and it's something I see and been telling customers or home owners for years and years
Many don't believe it. They believe some other UA-cam video where the guy does some supposed testing but at the end of the video still recommends what I did lol. Kinda crazy.
Yea look the real answer is I can do whatever the home owner really wants but do you want to pay for it.... as long as the engineer knows what you want in your home system they can do what you want... but now you might need to install booster fans in some of the lines, or increase the size if your blower motor... maybe go with a two stroke compressor so it can ramp up and down better... you may have to bring in more fresh air and install a mixing box.... it's one of those things I tell people to not over think it... haha
When I replaced / upgraded my HVAC, I arranged for my intake air to be filtered twice.
The first filtering happens as the air enters the air return duct. Here I placed a rinsable, relatively coarse filter. This filter catches large dust, pet fur, and the like. When dirty I simply remove, rinse off, and return to use.
At the furnace I place the best / finest filter I can find. This filter catches everything else. With my pre-filtering, this filter typically does last three months of peak use.
Filter expense? Often you can save as much as 50% simply by buying the filters three or four (a case) at a time. Spare filters are stored in the furnace closet.
Thanks for your advice! Not only do I appreciate what you advise us to do, but I appreciate you clearly explaining why to do them. Also, I see all the specific brands that you use in your videos and try to implement them all in my own home. Again, its definitely appreciated, brother!
Good info as always! I always wondered if the "better" filter put a strain on your unit so I always stuck to mid tier. Also I bought 2 Levoit air purifiers (Core 300M i believe) for my home because I suffer from allergies about 6 months ago, and I would say by far the best investment Ive made. Im no longer sneezing constantly and my eyes dont itch near as much. Good content, even better to know I picked a good brand lol
Yes it will if not sized for opening you can tell when you turn it on by how much noise you here form the air going pass the filter. It shuld not whistle?
@@mathewoliveira9028 thanks for the info!
Very interesting. Also learned a new product out there. 👍💯
I use a merv 5 3M pleated. 18 bucks for a 4 pack. Change usually once a month unless usage is less. Unit is now 26 years old.
If you are building/own a home you can compensate by having a bigger/oversized filter to still have good airflow. I have never used them but there is UV lights that can be installed in the HVAC system to kill most bacteria, mold, viruses, etc. I am not sure if those are a good idea or the issues with them however. I would suspect that is not for most people.
If you look on the end of that filter you will read the MERV number. That 1500 is a MERV 12. I was told by the guy who just installed my new furnace to use filters between 6-8 MERV. He also said to change the filter every month.
You got good advice. Almost every AC tech I’ve talked to has advised against using anything above 8. I think I talked to one out of all of them that said 10 at the highest but he was in the minority. Appreciate the feedback!
@@HowToHomeDIYYou're talking to techs not engineers. Bro please.
@@Slick1020so when the techs agree with the engineers we should then take the information provided by the engineers and throw it in the trash?
He’s right. I used these filters for 17 years and my furnace went kaput. Then I changed the blower motor starter capacitor and it ran another 8 until the unit developed a refrigerant leak and wasn’t worth recharging.
Really, you want to have multiple filters, coarse filters to remove large dust, then slightly finer ones to remove slightly finer particles. As a chemist, we often used 3-4 filters from coarse to very fine to filter air or liquids.
MERV between 8 and 10 are great for winter and 6 through 10 great for summer.
Appreciate the feedback!
Great video! I’m glad I see I’m not the only one that value the air we breathe inside our houses! I will just buy a bulk pack and replace every month or so but not 3 months . I know is about how heavy you hit the unit but why take a chance?
Higher MIRV filters do use the highly pleated filters. But I agree 6-8 or 10.
Very helpful. Thank you.
You are very welcome! Really glad to hear you liked it. Thanks a lot for the feedback!
Thanks so much for this video. it was so helpful.
Last couple of times I went down to Lowes, the lowest Filtrete type filter in 20x30x1 I could find was 1800. Literally, it was the ONLY choice.
I often get told by HVAC experts to to use use EZ flow type filters, and to just change them more frequently. I do use them, and I run free standing air cleaners in the house. The part I don't understand is why you would need to change a coarser furnace filter more frequently than one that traps a lot more dust and debris. If you change them once a month you are throwing away a filter that is still clear. Seems to me you should change the higher MERV filters more frequently, not the lower MERV.
@@crazydoglady5 Furnace filters? Wherever I can find my sizes. Sometimes Walmart, sometimes Amazon, etc.
@@gort8203 I looked on amazon but couldnt find THAT brand.
The high MERV Filtrete filters have a lot more capacity for holding small particles or dust and lint and hair *without* having a high pressure drop. I run my furnace recirculation fan 24 hours a day on the low speed to ensure uniform temperature and to pick up any dust that is generated. Those see through filters might pick up some pet hair but there is no benefit to changing them when they have nothing on them. The higher MERV rated filters are fantastic and you will notice that all the horizontal services in your house are cleaner with those in place
@@crazydoglady5 I but them online and always keep a spare or two. I have to set a reminder on my phone to change them as I don’t notice any and performance over time
@@davidsamsonite5791 I set mine on the fan running constantly and AC man that installed it said not to do that. It feels like dead air without it running so that's why i did it. But havent since. the higher the rating..the less air that can go through them. While i do buy the higher rated ones..i have heard not to do that. I been using merv 11. guess i should drop back. I also have the same air purifier as this fella doing the video. I would like to add another..but dang..the filters are expensive. I found my honeywell 200 has alot cheaper filters....and you change charcoal filter more often.
I use a washable filter that has a static draw to capture the dust. It was amazing the 1st month that I used it.
They don't last very long!
I just sent back my order of those and ordered ones like you recommend :)
I use a permanent washable air filter. I have two, to swap out when needed. The older one does does not have a MERV rating as that rating was not available for reusable filters at that time. The second one does have a rating, but I can't recall the number. Both filters are easy flowing for the blower and the airflow causes static charge collecting much more as those blue spiderweb filters. They clean easily, I use a battery powered wand, but any hose and sprayer would work. I enjoy watching the mud wash away until it comes out clear. Let it air dry and put away until the other one is dirty. They are a little spendy, but that one time cost has paid for both of them several times and many more to come.
Project Farm tested and found higher pleats with better material and higher MERV can have better air flow than low MERV with bad material and few pleats.
Thank you! I watched this video a long time back and it changed how I purchased my filters.
Yep. The Filtrete 1500 has really high pleats and good flow, better than their 1200 filter. Found a website that tested Filtrete and other filters that they sold I switched from the 1200 to the 1500. Been using the 1500 filters for nearly 20 years, never have called AC guy. I get annoyed by people just yacking about filters with zero evidence to back up the claims. Filter material and higher pleats make a big difference in performance.
@@Taluvian I agree with you. I have been using the 3M filtrate and never had a problem.
@markmalyn3861 3M Filtrete is a brand and model. I never said anything about the two as a product. 3M makes some of the best filters on the market. That’s not what the video is about though or what I was referring to. It’s all about the MERV rating regardless of brand.
@@HowToHomeDIY I've been using the 4 inch 1550 3M filter without any problems.
I use an electrostatic filter in my air handler. Amazing the air flow since it's a mesh and uses a electric current to attract stuff in the air of all sizes. We also do have air purifiers in most rooms since allergies is a problem. We also have uv light and an oxidizer. Expensive but we really think it helps.
One other thing that should be pointed out on using the higher MERV rated filters is that as they fill up with particles, the air pressure can eventually pull the filter in towards the fan; thus deforming the filter and making it hard to replace. I have had the happen a couple times with mine. When doing work/projects around the house or during pollen season, I will use a higher MERV rated filter for the whole house but check and replace often. The small portable air filters are nice but limited. I have both a small and large one that I've used for over a dozen years but they only have the capacity for up to a large room, like a living room. If you think house filters are expensive, just wait till you see the price on the air purifier filters!
I use a Molekule Air Purifier and I love it.
Someone living in AZ where the summer months we run the ac 24/7. I was tired of replacing them twice a month so I bought merv 4 washable filters. Buy two sets and while one dries the other set is filtering away. Swap out and wash the dirty one and let it dry and store it till have to swap it out again. Yes more up front cost but four total for $120 and been using them for 3 years and still look brand new. Would have spent $360 in that time with disposable filters st $5 a piece
I learned this one the hard way. I always replaced the merv1 filters my apartment would install and put in my own (typically MERV 14).
One day I got a call from my wife who told me the AC wasn't working and I asked her to check the filter and she sent a photo of our evap coils behind the filter completely covered in ice. Luckily the ice melted and the unit started working again. Since then I've only used the super low rated filters and have an air purifier.
I specifically asked our installer and he said to get Merv 6, but that may simply be model dependent too.
I use 5-8 and run 2 air purifiers. Im renovating and wind up changing main filter every month. I looked up my HVAC model at the manufacturer to find the recommended merv.
Amazing how many people have no idea they are suppose to replace their furnace filter. I saw one house where it was so clogged it actually tore the center out and it was flapping with the air flowing causing an annoying airflow up down noise in the registers. Just crazy.
I use a regular box fan for white noise when I sleep in which I got a MERV 8 taped to it... I got another box fan I run through the day at the other end of my apartment- that's got a merv 8 taped to the back of it also. The filters get changed every 3 months or when I notice them getting visibly dirty. My lung feels great :)
Do much the same!
Box fan in bedroom with 3x carbon layers
It will work better if the air has a chance to expand use a card bord box betwbetween the filter and the fan. It will be quieter as well.
Just one lung?
I bought a 20-in box fan made by Lasko off of Amazon that has a filter holder in it so you don't have to tape it. I think it's called a dual Flex or maybe an Air Flex.
Well , your furnace (probably) has a max rating static duct pressure ( probably on the door or inside floor label. I bought a manometer to measure my 96 % furnace ( repair guys around here don't carry those with them - why I don't know). I found the only way to get to 0.8 ( my furnace's max rating) was to use the lower MERV filters you describe ; plus I cut in another two high returns to increase return flow.As you said , more resistance means more wear on the blower. The ECM blowers are not as robust as the old AC capacitor types. As a bonus I was able to use the manometer to adjust the gas pressure to where it was supposed to be. I change the filter every 6-8 weeks. If you have critters , best to use a shorter interval.
What do u mean by critters?
@@naughtyorgneiss “Pets”.
I use both the low cost filters on my cold air returns and a media filter in my HCAC plenum.
I find that I only like those type of Filtrete filters that have the very many pleats or very high surface area. I used cheap filters and found they would clog up and really block airflow and sometimes even bend out of shape to allow air in. The high end Filtrerte seem to stay cleaner for much longer, which still providing adequate airflow. I don't care about the number, but want the high number of pleats.
I do use those in the summer house. Guess I'll start using a filter with a little less flow resistance. In the main house we've got one of those whopping big half a foot thick filter mechanisms. Not sure whether it was worth it or not but it works well for us. There's no need for such a good filter in the summer house anyway, it's not exactly a modern air tight house. No matter how much the filter removes more is always coming in :)
A tiny levoit air purifier will only clean one small room, while the lack of a good filter will spread allergens throughout the house. It's also backwards in that you are allowing allergens into the house and then having to suck them up again.
Wait! Did I just watch a 12 minute advertisement? You never addressed the fact that in many new homes there are multiple air returns, each with an air filter, and not just one at the furnace. For example, my home has 4 returns. This dramatically increases the total number of square feet available for air to pass through which reduces the load on the HVAC system. Also, that 3M filter has roughly 2-3 times as many pleats as the cheaper filter you showed. That represents 2-3 times the surface area for air to pass through and is another way the load on the HVAC system is reduced. Having said that, I too wouldn't use the 1500 series filters. I do use MERV 11 filters in my system as I believe they provide an good compromise between air flow and air filtration. My HVAC system is 27 years old and the fan, etc. is doing just fine. Project Farm has done actual data driven testing of HVAC filters. I would recommend your viewers check out his videos.
No you watched a 12 minute video on what has been passed on to me by actual HVAC techs (every single one of them) and what I have personally been using for years that I paid for myself. I am giving the info I have and providing what I use as people ALWAYS want to know. Your house is different than many. Mine is newer and there is one. Either way I wouldn't use the higher MERV filters. But do as you please!
Agree with both of you. We really need someone to test these various filters out after putting gunk them. Can measure draw from the fan, filtered air quality effectiveness after said gunking, and/or measure airflow to determine if this is just knowledge passed along in which we don't know the original idea behind it.
@@HowToHomeDIY Fair enough and I sincerely apologize for accusing you of something you did not intend to do regarding advertising on your channel. Having said that, after 45 years working in a data driven profession (physics), I stand by my comments regarding air filters. As offensive as it may be, the “opinion” of HVAC technicians doesn’t do much for me and that’s why I advocated your viewers consult actual testing results of various filters on sites like Project Farm. History is replete with examples of “facts” that were eventually debunked when someone actually bothered to collect the data. I believe your viewers would be better off if you did that here.
@@MrLuigi-oi7gm And that is YOUR opinion. Which you are entitled to.
@@HowToHomeDIY I would have hoped for a more reasoned and reasonable response to a request for actual experimentally determined data to support the argument you made in the video. Aristotle would have loved you. Galileo, not so much.
I have a home that I built in 1992 is about 2000 SQF and has a whole house heating and cooling system on the roof (California type install). I have been all over UA-cam and the advise by installers and people who service is the same as yours. I have a little bit of a problem that appears difficult to deal with. My air return is a rather large size being 20X30X1 what I noticed upon serving the system is that much of the service area is not used all that much. It is very clear that about 2 to 3 inches on each side is not used and remains clean and the middle is where the dust and dirt accumulates. I was thinking about using a 20X30X1 electrostatic filter as a base and getting the merv8 8 filter material to use on the outside of that as I need a base. Though It is probably way cheaper to just use a merv 8 is easier, if I can find them in the size I need. That is not all that easy, perhaps online.
My AC-guy recommended to use a cheaper filter BUT change it monthly. I have seen that Merve-1 filter you first showed collapsed when dust collected heavily.
Because the prices of MERV 7-8 disposable paper filters have "gone through the roof" I replaced them with washable aluminum filters with an electrostatic layer. Cleaning procedure is simply spraying with non-high pressure water in a direction opposite to air inflow once every 4 months and reinstalling them when dry. After a couple of years I've recouped the higher initial cost of the aluminum filters. I've noticed NO decrease in air quality, and I have bad allergic rhinitis.
I use them and I like them, a noticeable difference in dust from the cheap crap to these. And I can afford to pay for the additional costs of operation since it's easier than dusting the entire house. I also run a separate hepa filter in the house. I have allergies and asthma, never open the windows, so these filters are a must-have for me.
I've often felt that there should be a mid-range between the flimsy filter that blocks nothing and the fat filter that is too thick. But I'm lucky to find a filter with my dimensions, much less have a choice of thickness.
Edit: Thanks for mentioning that dirty filters can affect how long a furnace runs. I've been blaming my thermostat, but maybe it's my filter.
I think high merv filters maintain similar airflow compared to low merv filters because they are designed to do that with a lot of pleats. I've tested airflow with an anemometer and didn't see any difference. I also tried a very high merv 2" filter in place of the normal 1" and there is a noticeable difference in airflow but I'd need to modify the intake and the 2" filters are pricy. I worked in a large network facility and everything was about airflow and hot/ cold isles to keep all the equipment cool so we did a lot of testing and i became interested in my homes ac system. I definitely agree with dedicated air cleaners and keeping ac filters clean but I still think high merv filters have similar airflow as cheap filters while filtering out much smaller particulates. Imho you are paying more for these filters because they have better filtration while maintaing airflow. I've been using 24 x 24 1500 Filtrate filters you show for years and am very happy with them. They fit really tight too which none of the cheapies do with huge gaps. The 1500s actually snap in to my frame and some of the cheap ones will fall out when the grate is removed because they fit poorly. I think some air will leak around cheap filters too. All in all great video with lots of good info!
I use merv7 , and a fiberglass filter(roll) at the air intake vent to remove pet hair/bigger particles
When I used these charcoal filter type air purifiers, I had problems with thick mucus that would wake me up in the middle of the night to hack- brownish and causes coughing. The charcoal filter is the culprit. When I stopped using the purifiers I stopped getting the mucus
If you're not on top of replacing those "better" ones when they're supposed to be changed, it restricts a lot of air, other than the cheaper ones. Also, if the air is damp outside, once those "better" ones get exposed to moisture, they'll restrict a lot of airflow because the fibers swell. If you pay attention when you're switching out a "better" filter, its middle is almost always collapsed inward towards the fan, due to it not letting air pass through. The cheaper filters don't do that unless its been neglected for about a year after it was supposed to be replaced.
All very good and accurate points that I have see as well. Thanks a lot for sharing your observations and feedback!
You've pretty much confirmed half of my strategy here - my furnace/AC is running a fairly low-MERV filter to maximize airflow.
However, HEPA filters often don't move enough air to get things purified. They're great at removing things from the air that they do move, but they don't move much. A filter that moves enough is going to cost you a LOT of money.
I have a high-MERV 20x20x1 furnace filter attached to the back of a box fan running on Low instead. It filters far more air for the dollar. I don't have the space for a Corsi-Rosenthal setup (4 filters in parallel making a cube with the fan), but those can move significantly more air than a single-filter setup.
Apparently putting it on the front with some enclosed space between the fan and the filter can further increase airflow and so efficiency
How often do you have to replace the stand alone filters and what is the yearly cost?