Відео

Hey! @Thomas6Anderson Thanks for sharing such a detailed perspective! You’re absolutely right, encapsulating an attic comes with unique challenges, especially in colder climates where R-60 insulation is required. Proper design is critical to address issues like managing moisture with vapor barriers and ensuring the insulation meets code while maintaining functionality. Encapsulation works best when the attic becomes a conditioned space, which can help protect HVAC systems and improve energy efficiency. However, as you’ve pointed out, it’s not a one-size-fits-all solution. Factors like roof pitch, truss design, and climate play a significant role in determining whether encapsulation is the right approach. 😄

Great question! @MrLMJohnson A home with an unconditioned attached garage and a shared attic space could be a candidate for encapsulation, but there are a few considerations: Air Exchange - Encapsulation typically works best when the entire attic is sealed off from external air, including the garage area. However, if the garage remains unconditioned, you might face challenges with air sealing and thermal bridging between the garage and the living space. Ductwork Efficiency - Encapsulating can improve the energy efficiency of your HVAC system by reducing heat loss or gain through ductwork in the attic. Moisture Management - It’s crucial to assess whether encapsulating might trap moisture in the shared attic space, potentially causing long-term issues. Since every home is unique, it’s a good idea to consult with both an insulation professional and your HVAC contractor to evaluate your home’s specific setup. They can ensure that encapsulation would work well for your situation without compromising air quality or creating other concerns.😊

Good point! @ZimZam131 The surface area of a filter plays a huge role in its airflow resistance. A thicker filter, like a 4-inch MERV-15, has more pleats and surface area, which helps reduce the restriction compared to a 1-inch version. If you’re considering upgrading filters, it’s also worth checking that your HVAC system can accommodate the size and airflow needs. Have you noticed any differences in performance when using different thicknesses or MERV ratings? We’d love to hear your experience!

@@procalcsuniversity1484 My air handler only accepts a 1 inch filter. I also have the option of using my return vent to hold the air filter, which also holds a 1 inch filter. But after searching around I found a website that will custom make an A/C return vent that can hold a 4-inch filter. The cost was about $400 so I haven't pulled the trigger. Maybe next year, but replacement filters are also super expensive.

@timrothgeb416 Thank you for sharing your experience with radiant barriers! They’re definitely a cost-effective option for improving attic efficiency. In our video, we aimed to compare the broader benefits of vented vs encapsulated attics. Radiant barriers can complement vented attics, but in some climates or situations, encapsulated attics might still provide better year-round energy savings.😄

@darrenoxford2281 Thanks for sharing your experience-sorry to hear about your roof issues! Moisture management is definitely crucial in attics. Both vented and encapsulated designs can work well if done correctly, but as you said, ensuring proper airflow and moisture control is key. We always recommend consulting a professional to make sure the design matches the climate and build. Appreciate you chiming in! 😄

You need to call a professional before you or your loved ones don't wake up tomorrow. You're describing a potentially deadly situation in that home and extending your flue will do nothing to solve this issue.

Thanks for your comment! @seankoziel2261 Negative pressure and backdrafting can occur due to insufficient ventilation or pressure imbalances in the home. Since you've ruled out appliances and added vent height, the issue might stem from a tightly sealed home, blocked venting, or even a leaky return duct pulling air down. 😄

@@HVACinSC HVAC pro is going to add a fresh air intake to the furnace return

@seankoziel2261 I'm glad to see you're still alive. With this sort of issue, we usually just see the aftermath of CO/CO2 poisoning on the news.

Haha, that’s one way to look at it! Thanks for your comment. We think it would be best to focus on sealing entry points and proper maintenance as long-term solutions rather than relying on attic heat alone. 😄

Wow, thanks for taking the time to share your experience! @karenstein8261 That’s such an interesting setup you described, and it’s awesome to hear how the “cold roof” made such a huge difference in keeping your cabin cool. You’re absolutely right about what you’re describing works a lot like a ventilated roof system, where the airflow helps reduce the heat load on the structure. It makes sense that shading the cabin and letting the hot air escape before it even gets to the main roof would help so much, especially in a hot, sunny climate like Arkansas. When it comes to ASHRAE calculations (like Manual J), they do focus a lot on insulation values and materials, but they don’t always get into the specifics of unique roof designs like yours unless you’re doing more customized modeling. It’s more about overall energy performance and standard design conditions, so things like ventilation details can sometimes get overlooked unless someone accounts for them in a more detailed analysis. Your point about winter heating is really interesting too! It could be that the reduced sunlight in winter just doesn’t drive as much airflow through the vented roof, so the impact is smaller. It’s also possible that the overall heat loss from the cabin wasn’t as affected because of other factors like insulation or the natural heat retention of the masonry walls. I think your conclusion about adding a vented layer on top of a conventional roof is a great idea. It’s a practical and affordable way to get the benefits of shading and ventilation without a full redesign. The Scotch-Brite-style material to keep bugs out is a clever touch, too! 😄

I concur

Your problem wasn't the sealed flat roof, it was far too little insulation. Your flat roof would have been perfectly fine with an adequate amount of insulation, probably 3x what you had.

@@dlg5485 You bring up a valid point about insulation. Roof performance is definitely a combination of multiple factors, including insulation, ventilation, and the materials used. In the case of the flat roof, it’s possible that increasing the insulation could have helped reduce heat transfer. However, the ventilation and shading provided by the pitched roof clearly played a crucial role in this specific example. 😊

Thank you for your comment and for taking the time to point that out! You bring up a very valid point about calculating heat loss in a conditioned attic. Typically, heat loss calculations for a conditioned attic involve both the ceiling and roof, and depending on the design, roof surface area does indeed play a critical role in the total heat transfer. Additionally, the gable walls can also contribute significantly to the overall heat loss. In the video, we were aiming to cover the general approach to Manual J for a conditioned attic, but you’re right that for more precise calculations, both the roof and the gable walls should be considered, especially when it comes to larger surface areas. We appreciate your feedback, and we’ll definitely revisit the methodology in future content for more clarity.😄

Thanks for sharing! @jbaccanalia It's true that condensation can cause issues, which is why proper ventilation is so important. However, an encapsulated attic with the right insulation and vapor barriers can prevent moisture buildup and improve energy efficiency. It all comes down to the specific conditions of the home and ensuring the system is designed correctly. We always recommend evaluating the situation carefully before deciding.😄

Thank you for your comment! @davewillis264 Yes, heat escaping from the roof can indeed contribute to ice buildup or ice dams, especially in cold climates. When heat from the home rises into the attic, it warms the roof, causing the snow to melt. This water can then refreeze at the eaves where it's colder, forming ice dams. Proper attic insulation and ventilation are essential to prevent this. Insulation helps keep the heat inside the living space, while ventilation allows the attic to stay cooler, preventing the snow from melting unevenly.

Thank you! @KeneOliver We appreciate it 😄

@NovaNY347 Thank you for watching and sharing your situation! A radon mitigation system works by drawing air from beneath your home to reduce radon gas levels. This process can sometimes create negative pressure inside the house because air is being exhausted but not replaced. When your home is under negative pressure, it can pull air from any available source including the flue or chimney of your water heater. This backdrafting allows exhaust gases, like carbon monoxide, to enter your home instead of venting outside, which can be dangerous. Your HVAC system might help balance the pressure by introducing makeup air or adjusting airflow. However, depending on the extent of the issue, adding a dedicated makeup air system or other ventilation solutions may be necessary. We’d recommend consulting with a professional to ensure everything is safe and balanced. 😊

Thank you, Andrew. However, if you vent the attic, it negates the purpose of encapsulating it. When you encapsulate the attic, the goal is to bring the attic space into the thermal envelope of the house. With small cracks and gaps in the ceiling, such as those from lighting, a path is created for conditioned air to travel into the attic. This process slightly conditions the attic, reducing its temperature, the duct load, and the ceiling load, which in turn makes everything more efficient to operate. If you have implemented this approach differently and have documentation, I would love to review it. Please send it to Tom@procalcs.net. The world is always changing, and I’m always open to new ideas. Thank you for your comment. Please keep them coming - they keep me on my toes!

@@procalcsuniversity1484 I tried posting a link to what I’m talking about but UA-cam auto-deleted it. They don’t like links in the comments Basically you still encapsulate the attic but still vent the roof. From outside in it goes your roof sheathing, 1” air gap created using foam or plastic baffles (sold at all building supply stores), then your insulation. My preferred is rockwool then foil faced rigid insulation aiming for at least R30. Any more can be hard to achieve while still maintaining head room. The baffles vent the roof from soffit to ridge and/or hips. This venting also helps vent roof heat and moisture/condensation

Closed cell foam. No moisture problems

@@usmcfrommt9790 yes there is. Closed cell will hide and trap it worse

@@usmcfrommt9790 Thanks for sharing! Closed-cell foam is definitely a great option for preventing moisture issues when used correctly. It provides excellent insulation and acts as a vapor barrier.

Thanks for sharing your concern, @Anonsbdofjrnwodb We can't really comment on the studor vents since plumbing is not our specialty. As for AC, the most important part of preventing negative pressure is the air sealing of the building like you mentioned and sealing of any ductwork. A slim duct heat pump system will not automatically cause negative pressure if it is installed properly. The benefit of doing a mini split system would be the ability to separately control the temperature in the rooms where the two heads are. Which ever you choose, just make sure you get a Manual J calculated to make sure the system is the right size. An exhaust fan, if running for a long time or continuously could cause negative pressure, and in that case an ERV would be a better choice since it replaces the air it removes with fresh outdoor air. For a spray foam well-sealed house, an ERV is a great idea to provide needed ventilation for indoor air quality. I hope this helps! If you have any further questions, you can send an email to tom@procalcs.net

Hey @Kyle_Spivis, thanks so much for the feedback! I'm glad you found the video informative. A wood match can work as a substitute for a smoke stick, but it might not be as effective. You can also try placing your box fan against one of the windows pointing out to exhaust the air, and keep the ceiling fan running to help circulate the air in the room. Hope this helps!

Thanks for watching! @edmundotorquemada9941 We're glad you liked the video. That's a great idea, and while we haven’t covered moisture intrusion and its effects on homes under negative pressure yet, it's definitely an important topic. We’re planning to dive into that in future videos, so stay tuned! Feel free to subscribe for updates 😄

Thanks for the comment @viniciusbraga5846 ! That’s an interesting scenario, and we’ll definitely consider making a video to explore the differences between those setups. Stay tuned! :)

Good point, @Mikecianfrocco Without a proper return air path, especially when doors are closed, it can create pressure imbalances in the room. Thanks for highlighting that :)

Hello, @gregswank4912 thanks for sharing your concern to us. Could you provide the specifications or capacity of your bathroom and kitchen exhaust fans? Also, how airtight is your home? These 2 factors will significantly affect outside air strategy.

You're welcome, @vince8087! We're glad you found the video helpful. We're working on creating more content like this, including digital products that cover the basics of HVAC design, including Manual J calculations. Stay tuned for more updates! 😊

Hello, thank you for your comment! Given your current situation of having negative air pressure in your condo, ensure that your windows, doors, and any other openings are well-sealed to prevent air from escaping, which can help maintain the positive pressure you create. Also, try to limit or adjust the use of bathroom and kitchen fans, as they pull air out of the condo and increase negative pressure. Additionally, appliances like dryers and kitchen hoods that exhaust large volumes of air typically need makeup air to prevent significant negative pressure inside when they are in use.

@@procalcsuniversity1484 excellent thank you. anything I can buy like an erv or some kind of device to put in the window?

@@TecraTube Yes, an ERV can also help manage the air pressure in your condo. However, we highly suggest having your condo inspected first by professionals to assess your specific needs and recommend the best product for your situation.😊

Thank you for your support! @liyusuf7713

Hello, @moreglistrefine1432 thanks for your comment! Normally, higher positive pressure pushes out humid air, reducing indoor humidity, while negative pressure can draw in outside humid air, increasing indoor humidity. In your case, the larger return duct could make the house negative and might be affecting airflow, potentially drawing in more outside humid air.

Apologies the link isn't working. By pen, do you mean a smoke pen? If so, heres a link you can use: amzn.to/3HsM1y1

Thank you for sharing your insights! Metal roofing does sound like a great alternative, especially with the added benefit of sound reduction when using closed-cell foam. :)

Thanks for your comment @TJ-22! Typically, you can determine the type of windows in your house by examining them closely. A simple way to know is to look closely at the cross-section of the window glass. Single-pane windows will have just one layer of glass, while double-pane windows will have two layers separated by a spacer bar, and triple-pane windows will have three layers separated by two spacer bars. Or you can also look for any labels or markings on the windows themselves, as manufacturers often include this information. Additionally, you can consult any documentation or records you received when purchasing the house, as they may contain details about the windows installed. If you're still unsure, a professional home inspector or window contractor can help assess the type and condition of your windows.

@@procalcsuniversity1484 when I hold up an object, I see two different reflections. Therefore, it must be a double pane.

​@@TJ-22 That's a good observation! Another great way to check for the type of window you have is when you hold a lighted match. If you can see two reflections from a slightly off-center angle, then it's likely a double-paned window.

Hello @ccroney00 Thank you for your comment. It is possible that the negative air pressure in homes potentially causes headaches, although it's not a direct or universal effect. Headaches can result from various factors related to indoor air quality and comfort, which can be influenced by negative pressure. In your case, if the master bedroom consistently feels warmer while the other bedrooms are colder, it could indicate that there's an imbalance in the airflow within your home. This could be due to problems with the ventilation system, such as inadequate exhaust or improper distribution of air. It would be best to have a professional come out and inspect your system. It could be that the room, in particular, has higher pressure than the rest of the house because it does not have a return, or the supply is putting too much air.

Hello @ryanl6722! Thank you for your comment. It sounds like you're dealing with a challenging situation. Could you please share the results of your blower door test and the size of your house? Typically, since exhaust fans are intermittent and have a smaller CFM compared to the total volume of the house, the pressure differential created by them isn't usually a big concern. It primarily increases infiltration. Regarding the air coming in through the fireplace, closing the flue might help, but it could redirect air through other openings.

Hello, @GaddarKerim1 Thank you for your question! When considering whether to use hygienic flexible aluminum ducting in homes, the decision depends on several factors, especially the cost and specific needs. Hygienic flexible aluminum ducting tends to be more expensive than standard flexible ducting. If you have specific needs or concerns regarding air quality, allergies, or other health-related issues in your home, investing in hygienic flexible aluminum ducting may be beneficial.

@@procalcsuniversity1484 thank you.

@@GaddarKerim1 You're welcome! 😃

Thank you for your question! @kirthivasank2649 In a typical 1-ton air conditioning system, the pressurized gas refrigerant leaving the condenser can be around 90 to 135 degrees Fahrenheit (32.2 to 57.2°C) .The exact temperature depends on the pressure and load.

Hi Michael! It sounds like it definitely is possible you have an issue with negative pressure causing some temperature problems. But since you mentioned the temperature difference between upstairs and downstairs, it could also be due to the location of the thermostat if there is only one. If the thermostat is upstairs, it's possible the system is only running until the upstairs reaches temperature, but that isn't enough time for the downstairs to warm up enough. Since warm air rises, the upstairs will always be a bit warmer than downstairs. This is why we always recommend having a zoned system, with a separate thermostat on each floor. Of course I don't know your exact setup or equipment, but it is something else you can look into.

Hello Jorge! We're glad you found our video informative and interesting! It looks like when the dog door is being pushed out, the pressure inside is higher. For homes, we want to have a slight positive pressure as that's better than negative. Here are some steps you can take to address this issue: 1. Inspect the seals and gaskets around your sliding glass door to ensure they are in good condition and not allowing air to escape. If they are damaged or worn out, consider replacing them to improve the overall insulation of your door. 2. Many dog doors come with adjustable settings to control the sensitivity of the flap. Check the user manual or product documentation for your specific dog door to see if you can adjust it to require more force to open. This might prevent it from being pushed open by the air pressure. 3. If you're into DIY, you may also place a magnet on the sides of dog door to create a better seal and minimize the amount of air escaping. It would also be best to have a professional come out and inspect the system. Hope this helps!

Hey there! We appreciate your kind words and we're thrilled to hear that you enjoy our videos! 😊 Your concern about your HVAC company's proposed installation is valid, and it's important to ensure that any modifications to your HVAC system are both effective and safe. Here are my thoughts: Given that you live in south Louisiana with high humidity levels, controlling indoor humidity is crucial for comfort and preventing mold and moisture-related issues. If your system was not designed to have outside air added before, you'll want to have a load calc completed to make sure the system can handle the additional hot air and humidity. And also, it's always a good idea to get multiple opinions from different HVAC professionals. Have another reputable HVAC company evaluate your home and provide recommendations. This can help you compare different approaches and determine which one is best suited to your specific needs.

Hi there! We'd be happy to help with your HVAC concerns. Please feel free to email us at tom@procalcs.net along with your address. We'll do our best to assist you with any questions. 😊

Thanks for taking the time to watch our videos and sharing your suggestion! I think your idea is awesome! Stay tuned for upcoming contents, we'll definitely keep your suggestion in mind as we continue to create. 😊

Glad you loved the video! We're pleased to hear that you found it helpful and accurate. Living in South sounds like quite the challenge with the intense heat and if you're considering an energy inspection, that's a fantastic step toward optimizing your living environment and potential saving on energy cost too!

Good question! We would only add the square footage of the attic in if it is a finished attic that is being conditioned, otherwise just a vented or encapsulated attic it does not get added. 😄

We're glad you appreciate the video! Apologies for the broken link but here is a similar item from Amazon where you can get it. This is a tabletop temperature and humidity sensor: www.amazon.com/ThermoPro-TP55-Indoor-Thermometer-Touchscreen/dp/B06XTPTG1J/ref=sr_1_16?crid=2Z6G5QJBAX741&keywords=portable+thermostat+hygrometer&qid=1690557010&sprefix=portable+thermostat+hygrometer%2Caps%2C98&sr=8-16

@@procalcsuniversity1484 Thank you, I actually have this model and it’s unfortunately not most accurate. Can you suggest a more industry standard version please?

@@sp1200M3D Definitely! Here is the best pick for hygrometers. www.amazon.com/Ideal-Sciences-Temperature-Monitoring-Historical/dp/B01HH7YD2Y?th=1 If you want to know some of the best hygrometers out there, check this out. There's also Pros and cons listed to help you decide which one to buy. www.weatherstationadvisor.com/best-hygrometer-reviews/ Hope this helps!

Wow thanks for sharing that, that was interesting.

There could be a few things causing the issue, it's hard to say without more details. It's possible that your system is undersized now since adding the additional conditioned space of the finished attic, unless you had a load calc done to check. It also sounds like the master bedroom may not be getting enough air now, and if the supply grille in the master bedroom is the wrong size for the amount of air, that can cause issues with hot spots. A return in the finished attic would be recommended though either way, and per most codes is required when a room is occupiable and has a door that can be closed, like a bedroom or office. It would probably be a good idea to have a load calc done, as well as the duct system evaluated to try to pinpoint the issue. If you'd like to discuss further, feel free to send me an email at dana@procalcs.net. -Dana, ProCalcs LLC

Thank you and we don't currently have a course to teach these skills but here is a resource you can check out for now. www.wrightsoft.com/Training_Support/Mitek-Wrightsoft_Right-University/HVAC_System_Design/LCmid/10392/filter-page/3

What software is that

Good morning, Frank. Here is a good resource from Wrightsoft for you to check out. www.wrightsoft.com/Training_Support/Mitek-Wrightsoft_Right-University/HVAC_System_Design/LCmid/10392/filter-page/3

Thank you, Frank!

Thank you so much!