I have a solar designed home in Perth, Australia, that I designed and built in 1988 without mechanical air conditioning, and with only passive ventilation. The house uses thermal mass and never overheats in the summer, and requires very little none passive heating in the winter. If it does start to get warm inside after a couple of weeks of 40+ degrees, I open the windows and use mechanical extraction fans in the evenings and overnight to expel any excess heat. The excellent results are due to effective design and good insulation in the walls and ceiling, no architects needed. I have in recent years considered adding double glazing to the north facing picture windows, but have so far not found it to be needed.
We rent the apartment short term and unfortunately not every guest will consider our comfort systems and energy efficiency goals. We just don't want to offer the option of AC and risk someone setting it to 18 degrees 24/7.
One thing I would like to suggest, Considering that you have invested in a in ground pool, depending upon the volume size and depth of it, you could have used it for the cooling of your interior space If you had made a treatment ( like a live or faux plant overhang/pergola ) for shading especially on the high solar times of day, that water will stay cool throughout the day and easily below 20-22c even on the hottest days, if properly shaded, maybe using a light coloured pool cover during the day when pool not used and removing the cover at night ( to allow night evaporative cooling). If doing this you could use the pools thermal energy to cool your interior space with a W2A ( water-to-air ) heat pump instead of the A2A heat pump you have, water is a much more superior conductor of energy use, while using far less energy than air fans and pumps I’ve done this before in Africa and it works fantastically, easily shaving 40-60% off my cooling energy bill ( which is on PV), so a secondary unit (apartment) can keep their unit cool without affecting energy consumption Something to consider or test using a thermostat probe in a shaded pool on very hot days to track water/ambient air temperature variance
Interesting suggestions. Often the cost premium for deviating from a local standard solution makes innovation difficult to achieve. I would love to use the waste cold air from the pool and hot water heat pump to cool the house, but no such integrated mechanical solution exists. So we are stuck with a separate AC, HWU and Pool heater. Good for redundancy but not great for efficiency - although the solar PV is very effective at powering these at no cost for us during the day. BTW, we heat our pool to around 25-28 degrees in summer.
Great video and thank you for sharing but while it is true that the exterior of the building and air tightness is important, and glass shading is crucial, the insulated thermal mass of your slab is really what is helping you to ride out the day heat and into the generally cooler night cycle with lower energy use - lag time + coupled with clever sensible design - which you have shown. There is good material available on performance benefits of light coloured cladding (such as Coolmax roofing) but you are right that overall design is probably more important - but bad structual design coupled with dark colours will make things worse. The thing with your dark walls is although it does suck in more heat it seams that material plus the backing arrangement provides little thermal mass for that heat to sink and radiate from for hours - which is why brick walls isn't the best exterior cladding for many climates. The vent system behind the tin walls may provide some venting but most of the heat heading internally would be radiant heat which is in the infrared spectrum and doesn't vent via convection - I assume you know this which is why I don't see any of those whirly-birds on your roof - good choice. But it makes me wonder if you have a reflective barrier in your walls (vapour permeable) which is reflecting the radiant heat out (25mm air gap required). The other negative for dark colours is that it heats up the surrounding neighborhood (urban heat island effect). Efficiency Matrix just did a video test on special paints you can watch here: ua-cam.com/video/V8dg1ePdJ68/v-deo.htmlsi=6kUbSGeQDBP0CyJw I also recommend their blockwork video: ua-cam.com/video/rrWdTVE1M_4/v-deo.html I have just replaced my concrete tile roof with Mars terracotta from Monier which has a lower SOI compared to the prior roof. With terracotta having more thermal mass SOI is important. I also have R6+ glasswool insulation and non-reflective vapour-permeable membrane sarking (I am in Melbourne) which is essential when you insulate the roof cavity to a high standard to manage condensation on the back of a tile. It took a long time to explain to a well known roofing brand in Melbourne why you should not being using non-permeable silver sarking when you insulate thoroughly in a cool climate. The bush fire smoke prevention you described is down to the filters and the capacity of the filter to screen out particles of sufficient size. With smoke being between 0.5 and 2.5 microns in size I would be curious to know what your particulate filter is capable of. In addition the ability to keep your home positively pressured with clean air really helps keep smoke out (noting your house is passive tight). This principle is behind clean rooms used by industry. In regards to the Daikin heat exchanger cooling performance usually stops with an ambient external air temperature around 44-46C degrees at this point you are reliant upon your slab to keep the home cool (this is when ceiling fans become important for keeping the people feeling cooler than ambient - breeze). Your additional air transfer fans are really good. But they also have a role to play in managing the stack effect in two story dwellings with open stairwells. Have you used these this way in your projects in addition to a HRV? I really enjoy your videos and its really encouraging to see quality architectural design that doesn't cost the earth being promoted. I hope you get more subscribers and I appreciate being able to see some of your building designs and floor plans on your website and videos. It would be amazing see the project home builders promoting and building quality homes and not just the biggest thing with lowest efficiency they can ram on the block to unaware home buyers.
Wow, thanks for taking the time for such a detailed comment. I agree that the slab does have a stabilising effect on the the internal temperature. It certainly feels cool under foot, but Passive House software does not take Thermal mass into consideration. If anything the software penalises slab on ground for the heat loss effect.
@theleanarchitect Interesting but I suppose discounting the slab makes sense for a German designed approach to energy where sun heating during winter and cooling retention in summer isn''t available to them to such a degree. If you haven't seen it The Harmony house is a good video to watch - not everyone wants a HRV dependent based house: ua-cam.com/video/GPZMkRxoTNE/v-deo.htmlsi=p1sGEXW13-ROvYlX and this house is a good insight on what you can do with traditional plaster: ua-cam.com/video/pRXsumjJbNE/v-deo.htmlsi=1AaRyG8QTWrfkR23
Great dialogue This has always been my nemesis, the vast majority of information on passive design has been written for climates that have great temperature variations, like northern hemisphere, vs warmer climate zones Thermal mass energy storage is the best friend for both climate zones, just the treatments for them are different Having done many in North America and now focusing on hot/humid climates I am addressing the same solution but thinking differently I use a thicker slab with a similar ext. perimeter thermal barrier and depth, and also I use more thermal mass inside the house for retention than other passive house designs in Europe. I find homes in the hot climate zones easier to design than the ones I did in places like Canada Because the intensity of heat is only limited to a few hours of the day ( mostly 9am to 5-6pm) with the remaining 15-16 hours becoming temperate. Versus in places like Canada for 3-4 months a year the day can be -15c to -25c and the night dropping off to -25c to -40c So the need for energy production and storage is paramount, furthermore 5-6 months later the design that was effective in winter is working against you in the summer which ranges from 30c to 40c This is why I approach this issue in hotter climate zones, where I am now, with more thermal storage (for the hot 30-35% of the day) and slowly releasing for the 15-20% moderate temperatures ( 5-6pm to 9-10pm) then I turbo-recharge my mass the remaining of the 24hr cycle (10pm to 6-7am) when outside temps are enjoyable I find this works best in environments where the variant from outside temps ( days high to nights low) is no less than ~10-12c, ideally 15c Which I believe Australia is in that range ( ie daytime high 38c overnight low 23c ) Of course there are many other factors to passive design and execution but….. Just my 2cents
@alawoye Interesting comment. Being aware of your environment is super important for design. Australia has varied climate options. Not as cold as Canada but cool climate living (-10c nights to 5C days) to desert to tropics.area all here for architects to design for.
@@And-c7n We live in Climate Zone 5 which is Warm Temperate. This would suggest that winters are comfortable, when in fact they are quite cold by Australian standards. Having previously built and lived in a modern Solar Passive Home that relied on Thermal Mass, I can tell you that it means absolutely nothing if you have excessive heat loss through the thermal envelope (walls, roof, glazing and thermal bridges). The home would collect winter sun easily and heat the part of the slab that received direct sunlight, but overnight all the heat gains would be lost. Its a hopeless system.
great video mate, you've done it so well with a selffy stick (im assuming), looks pro....most importantly its great to illustrate to people that PH isn't just for Europe , love it..also what a great job your guys did with the fascia/cappings, its so hard to get that looking flat even after some hot days
Thanks! Well done noticing the fascia and capping. Its the small things that elevate a building. Its th result of great work and collaboration by our builder and roofing trade.
Good point. Humidity is not such a big issue in our climate zone, but the HRV does a good job of keeping the internal relative humidity between 50-60%. This is very comfortable for living.
@@theleanarchitectthanks for your response because I was going to ask the same question. I have done a few passive house projects in North America and now I’m on the African continent, the issue of heat and humidity including interior moisture is the main concerns, I also use ERVs to manage the humidity levels and keep the interior air quality high while keeping the heat out, I do passive cooling with thermal storage (no mechanical a/c) and it works fine even though our days often cross 40c and the nights barely drop below 30c ( during the hot season it drop to around 32-33c overnight by 5am before raising again) I’m doing this to tweak the design process for energy efficient homes, so I’m glad you made this video for hot climate zones
Humidity is biggest challenge for passive homes. I also live in 70-80% humidity region. Did not find an energy effective solution for humidity. Air conditioning becomes essential. Plz suggest solutions for high humidity homes
Thanks for sharing the insights into your house. It's generated some interesting comments, many of which are worth contemplating. One that jumps out is the facade colour. Our practice (of architects) has been testing this out. We're on the Midnorth Coast of NSW and we put the same house through the NatHERS engine with Shale Grey roof and walls vs Monument roof and walls and the difference was 0.2 star. So negligible. @FrankReif made the comment that ‘walking in front of a dark facade will feel significantly hotter during the day’. I’m not sure about that. Walking next to a white wall that is reflecting the heat back at you is more likely to be uncomfortable. Try being on a Zincalume roof on a sunny winters day and you’ll appreciate the heat reflection. There’s also a big difference between black masonry and black steel interns of how the energy affects the house or those outside it.
Thanks for sharing your research! We surface measured light and dark metal cladding in full sunlight and found only a small difference of around 6c or less than 10%. Not terribly scientific but interesting nonetheless. It would be interesting to put sensors inside the two wall options and measure the phase shift in real time.
@@theleanarchitect There are so many subtle differences and I'm not sure how much it all affects the end user. Good old passive solar design is the absolute go to as a starting point. The less machines and moving parts the better. One interesting thing I measured today was the heat of a concrete floor slab inside sliding double glazed doors. The doors were closed. Where there was no fly screen the slab measured 32.1C, where the crimsafe fly screen was in front of the glass the slab measured 25.9C. Outside temp 25C. How that affects the comfort of the house this evening is probably negligible! But interesting nonetheless.
I'm housesitting in a passive house and I asked the owner in advance if we could bring our potable air conditioner for upcoming heat waves. she said she'd rather us not because the house us designed to stay cool. I said "OH, so it actually gets cold in there during a heat wave, without air conditioning" She said she uses a fan and it's pretty cool in Summer. We'll here we are and the house will not go below 24 degrees. It doesn't matter if I set the base temp low, put it on auto or cool setting... the house does not cool itself at all when temperatures are 26 degrees outside. That's not even that hot for a Summer day yet the house has been the same temp inside as it is outside all day. 24 degrees is our night time temp. Meanwhile a healthy room temperature for sleeping (for optimal wellness) is 17-19 degrees. So essentially this passive house can't even get close to a healthy sleeping temp at night when it's not even a heat wave outside. This is pretty weak.
Where is the house you're referring to? I'm guessing northern hemisphere based on you saying it's summer and it's August. Is it an actual certified 'PassivHaus', rather than 'passive solar designed'? I guess the challenge relative to health is should we sleep at a natural room temperature of 24C, perhaps with a fan on, or use conditioned air and sleep at 18C?
Thermal comfort is entirely subjective. That said, 24 degrees is considered within the human comfort zone and the design parameters of passive house. Your expectation for 17-19 degrees night temps in a warming climate is unrealistic and reliant on the use of AC at a time of day when there is no renewable energy generation. If we actually want to live sustainably, people will have to adjust their expectations around climate control.
Have you tried something as simple as opening all the windows early when the air is cold, then closing them when the house cools and before it gets hot outside, and when the air gets stale, strategically opening a first floor window on a shaded and cool part of the outside, and open another window one the second floor, if in a two storey home or a 1st floor windows on opposite ends, to get fresh cool inflow?
Great video and build - well done! I've been curious about something: Is there an HRV/ERV system that uses two same-size whole house fans, one for intake and one for exhaust, connected to a smart switch? The idea is that on hot summer days, *if* it's cooler outside in the early morning, the smart switch could auto activate the fans to flush the house with cool air, helping it stay cooler throughout the day. Does a system like this exist?
Here in Australia we had a product called an Odyssey whole of house fan that did just that. It could purge a whole house very quickly and could be retrofitted to an existing home that is not necessarily built to be airtight. I don't think it sold to well because it no longer seems available. Here is the brochure www.bradfordventilation.com.au/-/media/edmonds/files/odyssey-brochure.pdf
I have 2 questions, 1. Do you hace a recirc kitchen hood or make up air for hood. If make up air do u have motorized damper or fan for make up air? 2. If building when it is hot, I'm worried about portable air conditioning because its a tight house and we r supposed to vent the unit outside so not sure where the intake air will cone from. Won't be able to get our house AC unit for a bit. Thx
Recirculating downdraft extraction built into the Bosch induction cooktop. No exhaust to the exterior other than that provided by the HRV. Portable AC not an option without an exterior exhaust through a window opening, and these need to be a sliding window (ie. not passive house ) to get a good seal. Our windows are typically Tilt & Turn or casement for good air sealing.
What system do you use for air transfer? We're finding similarly that the north-west corner of our house is a bit of a warm zone also and the HRV isn't capable of mixing enough cool air for the heat gain. FWIW we went dark Colorbond, although with a dark roof too because it was visible. With the ventilated cavities, it's performing great. Ironically the house is coolest around midday when the windows get a break from the east facing sun (we have shading yet to be installed).
For air transfer they are simple room to room inline fans with 150mm ducts. They move about 300 litres a minute. It would be great if these were upgraded to move more volume.
On the east side of the house, why didn't you use a roof overhang to prevent summer sun from hitting the glass instead of having to utilize the roller shutters and eliminating all natural light from that side?
Additional overhangs and eaves would have added significant cost and provide limited benefit against low angle morning (east) and afternoon sun (west). The main benefit of blinds is that they are operable. They only need to be closed when the sun is directly hitting the glass.
Hi, The floor plan is here: www.leanhaus.com.au/projects/2020/12/3/alderbury. Budget during covid was AUD$800k , although now it would be closer to $1.2m
Great video and I guess she likes you building angle but I don’t see any hot air or stale air tower chimney to evacuate the hot air out of the building. How you control hot and cold air flow in building. I m not an architect but I have interest in passive home. In USA/Mexico boundary they construct dome shaped homes with a small oculus opening at top of dome and temperature difference is 10 Degrees cooler than outside without AC.
The building has a mechanical heat recovery ventilation system that runs 24/7 and moves the entire volume of the house in 3 hours. It does not purge heat as quickly as open windows, so when we have cooling breezes we purge the heat. The point is that if you add coolness to the house via AC then t does not escape to the outside easily.
Hi, sorry to be that guy, but the ventilated void behind a facade removes negligible heat - this is a common misunderstanding in the industry. It is great at drying the cavity and providing a drainage plane. The colour does affect the local microclimate - walking in front of a dark facade will feel significantly hotter during the day due to infrared heat transfer - and a city full of dark roofs will create more of an urban heat island and cause more cumulative heat damage to PV systems. I like the internal recirculation on a single AC unit. Americans frequently use central return recirculation units, with the fan coil in the duct system instead, which are better with medium load buildings and climate zones needing more dehumidification.
I agree that the openings at the top and the bottom of the cladding may not ventilate all the heat trapped by the cladding. But it is better than no cavity. In this case we made a conscious decision to go with a dark cladding and the performance of the home doesn't seem to suffer as a result.
@@theleanarchitect Thanks for the reply. I can see how it would be tempting to use a concept like that to counteract the disproportionate emphasis you Ozzies put on cladding colours. But if the effect represents like
The colour does affect the local microclimate, however on the Midnorth Coast of NSW walking next to a white steel wall is much more uncomfortable due to the sun reflecting off it. It's amazing how intense the heat being reflected is. The dark steel reflects the heat too, but not as intensely. I'm sure this would be similar in many parts of WA. If the walls are masonry that would change the scenario. I'm really keen to see studies on the urban heat island effect with a comparison between steel and masonry roof types. I believe there's some study at Newcastle Uni in to this.
@@theowhite They're expensive to build, heavy, impractical to maintain, and are just worse than using the equivalent price for much more insulation. You're better off going for a standing seam steel roof, vented mesh to the ridge. It'll last 50 years with next to no maintenance, no problem. PV systems mount very well to the seams. And you can have it in any colour you like, if you're in an AC climate, by all means make it white!
Its 12mm square Acoustic plasterboard. Typically used in commercial projects but very effective in making the room quieter. Especially when concrete floors are combined with high ceilings, you get increased resonance.
one good thing about solar panels......they perform well on hot sunny days when running an air con is useful. I commend the use of small practical,sensible windows.....most homes have stupidly large windows for the Australian climate. Dark colorbond colours also fade sooner........any roofer will tell you that. Its stupid.
We have light coloured roof on this house - it is not visible from the street. I must admit that sometimes we cant avoid the dark roof but we take measures to negate its impact on thermal performance, such as ventilating the cavity and provide high density insulation with elevated specific heat capacity.
@@theleanarchitect I completely agree that the thermal affects can be mitigated........the problem is having faded colorbond colors dont hold the intended aesthetic effect for any length of time, by home standards. Homes are not cars.
since you basically have a very light colored roof I would have installed bi facial pv.lifted off of the roof a way so that light reflection can hit the back side of the panels . and a simple thermal solar to preheat the water.. From my understanding in your part of the world something around 46% of all power is being used to heat water.. Seems like a big load but that is what the installer was saying.
Thermal Mass is not a consideration of Passive House Software. The thermal stabilising effect of the concrete slab is not quantified but I believe it would be of some benefit in summer. However in winter you pay a heavy penalty for heat losses through the slab to the ground.
@@theleanarchitect that’s surprising, I would have thought in hot climates even more important. I was an architect, we did a house for an engineer, had solid concrete floors and concrete cored walls, he calculated it would hold six months of heat. ps. You always insulate below the slab in cold climates
@@theleanarchitect similar to our house KFW55 in Germany. KFW55 means the house consumes 55% of the energy the given reference house (conventional new build house) consumes. Standards are regulated by the GEG law and other norming rules in Germany: U-values (W/m2 k) of our house: roof 0.17, walls 0.23, floor 0.15, shaded balcony 0.15, windows 0.76, entrance door 0.76. (U=1/R)
We do have an openable window. However the ventilation system does a great job of drying out the room leaving it odour free with dry towels and surfaces.
Interior thermal comfort level is a personal choice that we discuss with client early in the process. If 22 is the standard required then we specify an appropriate cooling system to achieve that. For us, 25 degrees with 50% RH is more than comfortable.
@@theleanarchitect I agree that 25 is fine. It's all relative. It seems like the western world is obsessed with keeping internal temperatures at a constant 22 deg C. Keeping a house at 22 deg takes a lot of energy and embodied energy.
25 indoors in Perth is a very comfortable temp, with fans running. When I lived there prior to 2000, I would say majority of homes didn’t run aircon, we just slept at the beach when it was too hot!
I have a solar designed home in Perth, Australia, that I designed and built in 1988 without mechanical air conditioning, and with only passive ventilation. The house uses thermal mass and never overheats in the summer, and requires very little none passive heating in the winter. If it does start to get warm inside after a couple of weeks of 40+ degrees, I open the windows and use mechanical extraction fans in the evenings and overnight to expel any excess heat. The excellent results are due to effective design and good insulation in the walls and ceiling, no architects needed. I have in recent years considered adding double glazing to the north facing picture windows, but have so far not found it to be needed.
Love the videos mate. Think you're onto a winning market in Perth over the next 10 years.
Thanks Tom. Doing our best to design and build homes that actually work in the real world.
When it gets really hot, yours house becomes passive aggressive.
Like all other houses 🏘️
😂
Thanks for sharing; I love this style of construction especially when dealing with climate change
That's great to see more Passive Haus content in Australia but man the comment about limiting what your Tennant's do was a little off.
We rent the apartment short term and unfortunately not every guest will consider our comfort systems and energy efficiency goals. We just don't want to offer the option of AC and risk someone setting it to 18 degrees 24/7.
@@theleanarchitectAgree with your logic.
In 🇨🇦 we have the phrase: drive it like it’s a rental. 😮
One thing I would like to suggest,
Considering that you have invested in a in ground pool, depending upon the volume size and depth of it, you could have used it for the cooling of your interior space
If you had made a treatment ( like a live or faux plant overhang/pergola ) for shading especially on the high solar times of day, that water will stay cool throughout the day and easily below 20-22c even on the hottest days, if properly shaded, maybe using a light coloured pool cover during the day when pool not used and removing the cover at night ( to allow night evaporative cooling).
If doing this you could use the pools thermal energy to cool your interior space with a W2A ( water-to-air ) heat pump instead of the A2A heat pump you have, water is a much more superior conductor of energy use, while using far less energy than air fans and pumps
I’ve done this before in Africa and it works fantastically, easily shaving 40-60% off my cooling energy bill ( which is on PV), so a secondary unit (apartment) can keep their unit cool without affecting energy consumption
Something to consider or test using a thermostat probe in a shaded pool on very hot days to track water/ambient air temperature variance
Interesting suggestions. Often the cost premium for deviating from a local standard solution makes innovation difficult to achieve. I would love to use the waste cold air from the pool and hot water heat pump to cool the house, but no such integrated mechanical solution exists.
So we are stuck with a separate AC, HWU and Pool heater. Good for redundancy but not great for efficiency - although the solar PV is very effective at powering these at no cost for us during the day.
BTW, we heat our pool to around 25-28 degrees in summer.
Great job!!!
Great video and thank you for sharing but while it is true that the exterior of the building and air tightness is important, and glass shading is crucial, the insulated thermal mass of your slab is really what is helping you to ride out the day heat and into the generally cooler night cycle with lower energy use - lag time + coupled with clever sensible design - which you have shown. There is good material available on performance benefits of light coloured cladding (such as Coolmax roofing) but you are right that overall design is probably more important - but bad structual design coupled with dark colours will make things worse.
The thing with your dark walls is although it does suck in more heat it seams that material plus the backing arrangement provides little thermal mass for that heat to sink and radiate from for hours - which is why brick walls isn't the best exterior cladding for many climates. The vent system behind the tin walls may provide some venting but most of the heat heading internally would be radiant heat which is in the infrared spectrum and doesn't vent via convection - I assume you know this which is why I don't see any of those whirly-birds on your roof - good choice. But it makes me wonder if you have a reflective barrier in your walls (vapour permeable) which is reflecting the radiant heat out (25mm air gap required). The other negative for dark colours is that it heats up the surrounding neighborhood (urban heat island effect).
Efficiency Matrix just did a video test on special paints you can watch here: ua-cam.com/video/V8dg1ePdJ68/v-deo.htmlsi=6kUbSGeQDBP0CyJw
I also recommend their blockwork video: ua-cam.com/video/rrWdTVE1M_4/v-deo.html
I have just replaced my concrete tile roof with Mars terracotta from Monier which has a lower SOI compared to the prior roof. With terracotta having more thermal mass SOI is important. I also have R6+ glasswool insulation and non-reflective vapour-permeable membrane sarking (I am in Melbourne) which is essential when you insulate the roof cavity to a high standard to manage condensation on the back of a tile. It took a long time to explain to a well known roofing brand in Melbourne why you should not being using non-permeable silver sarking when you insulate thoroughly in a cool climate.
The bush fire smoke prevention you described is down to the filters and the capacity of the filter to screen out particles of sufficient size. With smoke being between 0.5 and 2.5 microns in size I would be curious to know what your particulate filter is capable of. In addition the ability to keep your home positively pressured with clean air really helps keep smoke out (noting your house is passive tight). This principle is behind clean rooms used by industry.
In regards to the Daikin heat exchanger cooling performance usually stops with an ambient external air temperature around 44-46C degrees at this point you are reliant upon your slab to keep the home cool (this is when ceiling fans become important for keeping the people feeling cooler than ambient - breeze).
Your additional air transfer fans are really good. But they also have a role to play in managing the stack effect in two story dwellings with open stairwells. Have you used these this way in your projects in addition to a HRV?
I really enjoy your videos and its really encouraging to see quality architectural design that doesn't cost the earth being promoted. I hope you get more subscribers and I appreciate being able to see some of your building designs and floor plans on your website and videos. It would be amazing see the project home builders promoting and building quality homes and not just the biggest thing with lowest efficiency they can ram on the block to unaware home buyers.
Wow, thanks for taking the time for such a detailed comment. I agree that the slab does have a stabilising effect on the the internal temperature. It certainly feels cool under foot, but Passive House software does not take Thermal mass into consideration. If anything the software penalises slab on ground for the heat loss effect.
@theleanarchitect Interesting but I suppose discounting the slab makes sense for a German designed approach to energy where sun heating during winter and cooling retention in summer isn''t available to them to such a degree.
If you haven't seen it The Harmony house is a good video to watch - not everyone wants a HRV dependent based house: ua-cam.com/video/GPZMkRxoTNE/v-deo.htmlsi=p1sGEXW13-ROvYlX and this house is a good insight on what you can do with traditional plaster: ua-cam.com/video/pRXsumjJbNE/v-deo.htmlsi=1AaRyG8QTWrfkR23
Great dialogue
This has always been my nemesis, the vast majority of information on passive design has been written for climates that have great temperature variations, like northern hemisphere, vs warmer climate zones
Thermal mass energy storage is the best friend for both climate zones, just the treatments for them are different
Having done many in North America and now focusing on hot/humid climates I am addressing the same solution but thinking differently
I use a thicker slab with a similar ext. perimeter thermal barrier and depth, and also I use more thermal mass inside the house for retention than other passive house designs in Europe.
I find homes in the hot climate zones easier to design than the ones I did in places like Canada
Because the intensity of heat is only limited to a few hours of the day ( mostly 9am to 5-6pm) with the remaining 15-16 hours becoming temperate. Versus in places like Canada for 3-4 months a year the day can be -15c to -25c and the night dropping off to -25c to -40c
So the need for energy production and storage is paramount, furthermore 5-6 months later the design that was effective in winter is working against you in the summer which ranges from 30c to 40c
This is why I approach this issue in hotter climate zones, where I am now, with more thermal storage (for the hot 30-35% of the day) and slowly releasing for the 15-20% moderate temperatures ( 5-6pm to 9-10pm) then I turbo-recharge my mass the remaining of the 24hr cycle (10pm to 6-7am) when outside temps are enjoyable
I find this works best in environments where the variant from outside temps ( days high to nights low) is no less than ~10-12c, ideally 15c
Which I believe Australia is in that range ( ie daytime high 38c overnight low 23c )
Of course there are many other factors to passive design and execution but…..
Just my 2cents
@alawoye Interesting comment. Being aware of your environment is super important for design.
Australia has varied climate options. Not as cold as Canada but cool climate living (-10c nights to 5C days) to desert to tropics.area all here for architects to design for.
@@And-c7n We live in Climate Zone 5 which is Warm Temperate. This would suggest that winters are comfortable, when in fact they are quite cold by Australian standards. Having previously built and lived in a modern Solar Passive Home that relied on Thermal Mass, I can tell you that it means absolutely nothing if you have excessive heat loss through the thermal envelope (walls, roof, glazing and thermal bridges). The home would collect winter sun easily and heat the part of the slab that received direct sunlight, but overnight all the heat gains would be lost. Its a hopeless system.
great video mate, you've done it so well with a selffy stick (im assuming), looks pro....most importantly its great to illustrate to people that PH isn't just for Europe , love it..also what a great job your guys did with the fascia/cappings, its so hard to get that looking flat even after some hot days
Thanks! Well done noticing the fascia and capping. Its the small things that elevate a building. Its th result of great work and collaboration by our builder and roofing trade.
Would be useful to discuss Humidity in relation to heat. Humidity impacts comfort as much if not more than heat.
Good point. Humidity is not such a big issue in our climate zone, but the HRV does a good job of keeping the internal relative humidity between 50-60%. This is very comfortable for living.
@@theleanarchitectthanks for your response because I was going to ask the same question.
I have done a few passive house projects in North America and now I’m on the African continent, the issue of heat and humidity including interior moisture is the main concerns, I also use ERVs to manage the humidity levels and keep the interior air quality high while keeping the heat out, I do passive cooling with thermal storage (no mechanical a/c) and it works fine even though our days often cross 40c and the nights barely drop below 30c ( during the hot season it drop to around 32-33c overnight by 5am before raising again)
I’m doing this to tweak the design process for energy efficient homes, so I’m glad you made this video for hot climate zones
Humidity is biggest challenge for passive homes. I also live in 70-80% humidity region. Did not find an energy effective solution for humidity. Air conditioning becomes essential. Plz suggest solutions for high humidity homes
Thanks for sharing the insights into your house. It's generated some interesting comments, many of which are worth contemplating. One that jumps out is the facade colour. Our practice (of architects) has been testing this out. We're on the Midnorth Coast of NSW and we put the same house through the NatHERS engine with Shale Grey roof and walls vs Monument roof and walls and the difference was 0.2 star. So negligible.
@FrankReif made the comment that ‘walking in front of a dark facade will feel significantly hotter during the day’. I’m not sure about that. Walking next to a white wall that is reflecting the heat back at you is more likely to be uncomfortable. Try being on a Zincalume roof on a sunny winters day and you’ll appreciate the heat reflection. There’s also a big difference between black masonry and black steel interns of how the energy affects the house or those outside it.
Thanks for sharing your research! We surface measured light and dark metal cladding in full sunlight and found only a small difference of around 6c or less than 10%. Not terribly scientific but interesting nonetheless. It would be interesting to put sensors inside the two wall options and measure the phase shift in real time.
@@theleanarchitect There are so many subtle differences and I'm not sure how much it all affects the end user. Good old passive solar design is the absolute go to as a starting point. The less machines and moving parts the better. One interesting thing I measured today was the heat of a concrete floor slab inside sliding double glazed doors. The doors were closed. Where there was no fly screen the slab measured 32.1C, where the crimsafe fly screen was in front of the glass the slab measured 25.9C. Outside temp 25C. How that affects the comfort of the house this evening is probably negligible! But interesting nonetheless.
I'm housesitting in a passive house and I asked the owner in advance if we could bring our potable air conditioner for upcoming heat waves. she said she'd rather us not because the house us designed to stay cool. I said "OH, so it actually gets cold in there during a heat wave, without air conditioning" She said she uses a fan and it's pretty cool in Summer. We'll here we are and the house will not go below 24 degrees. It doesn't matter if I set the base temp low, put it on auto or cool setting... the house does not cool itself at all when temperatures are 26 degrees outside. That's not even that hot for a Summer day yet the house has been the same temp inside as it is outside all day. 24 degrees is our night time temp. Meanwhile a healthy room temperature for sleeping (for optimal wellness) is 17-19 degrees. So essentially this passive house can't even get close to a healthy sleeping temp at night when it's not even a heat wave outside. This is pretty weak.
Where is the house you're referring to? I'm guessing northern hemisphere based on you saying it's summer and it's August. Is it an actual certified 'PassivHaus', rather than 'passive solar designed'? I guess the challenge relative to health is should we sleep at a natural room temperature of 24C, perhaps with a fan on, or use conditioned air and sleep at 18C?
Thermal comfort is entirely subjective. That said, 24 degrees is considered within the human comfort zone and the design parameters of passive house. Your expectation for 17-19 degrees night temps in a warming climate is unrealistic and reliant on the use of AC at a time of day when there is no renewable energy generation. If we actually want to live sustainably, people will have to adjust their expectations around climate control.
I'd love to have 24° C all day long!!!
Have you tried something as simple as opening all the windows early when the air is cold, then closing them when the house cools and before it gets hot outside, and when the air gets stale, strategically opening a first floor window on a shaded and cool part of the outside, and open another window one the second floor, if in a two storey home or a 1st floor windows on opposite ends, to get fresh cool inflow?
@@boxerfencer that is a great idea
wow you made it into our schools investigation booklet we have to watch your video lol
Great video and build - well done!
I've been curious about something: Is there an HRV/ERV system that uses two same-size whole house fans, one for intake and one for exhaust, connected to a smart switch? The idea is that on hot summer days, *if* it's cooler outside in the early morning, the smart switch could auto activate the fans to flush the house with cool air, helping it stay cooler throughout the day. Does a system like this exist?
Here in Australia we had a product called an Odyssey whole of house fan that did just that. It could purge a whole house very quickly and could be retrofitted to an existing home that is not necessarily built to be airtight. I don't think it sold to well because it no longer seems available. Here is the brochure www.bradfordventilation.com.au/-/media/edmonds/files/odyssey-brochure.pdf
Crikey Mate what an awesome house
I have 2 questions, 1. Do you hace a recirc kitchen hood or make up air for hood. If make up air do u have motorized damper or fan for make up air? 2. If building when it is hot, I'm worried about portable air conditioning because its a tight house and we r supposed to vent the unit outside so not sure where the intake air will cone from. Won't be able to get our house AC unit for a bit. Thx
Recirculating downdraft extraction built into the Bosch induction cooktop. No exhaust to the exterior other than that provided by the HRV.
Portable AC not an option without an exterior exhaust through a window opening, and these need to be a sliding window (ie. not passive house ) to get a good seal. Our windows are typically Tilt & Turn or casement for good air sealing.
What system do you use for air transfer? We're finding similarly that the north-west corner of our house is a bit of a warm zone also and the HRV isn't capable of mixing enough cool air for the heat gain.
FWIW we went dark Colorbond, although with a dark roof too because it was visible. With the ventilated cavities, it's performing great. Ironically the house is coolest around midday when the windows get a break from the east facing sun (we have shading yet to be installed).
For air transfer they are simple room to room inline fans with 150mm ducts. They move about 300 litres a minute. It would be great if these were upgraded to move more volume.
On the east side of the house, why didn't you use a roof overhang to prevent summer sun from hitting the glass instead of having to utilize the roller shutters and eliminating all natural light from that side?
Additional overhangs and eaves would have added significant cost and provide limited benefit against low angle morning (east) and afternoon sun (west). The main benefit of blinds is that they are operable. They only need to be closed when the sun is directly hitting the glass.
@@theleanarchitect I love the metal exterior. Beautiful home you have.
What was the budget for a house off this size? Would love to see a floor plan. Awesome job
Hi, The floor plan is here: www.leanhaus.com.au/projects/2020/12/3/alderbury. Budget during covid was AUD$800k , although now it would be closer to $1.2m
@@theleanarchitect amazing thankyou!
Great video and I guess she likes you building angle but I don’t see any hot air or stale air tower chimney to evacuate the hot air out of the building. How you control hot and cold air flow in building.
I m not an architect but I have interest in passive home.
In USA/Mexico boundary they construct dome shaped homes with a small oculus opening at top of dome and temperature difference is 10 Degrees cooler than outside without AC.
The building has a mechanical heat recovery ventilation system that runs 24/7 and moves the entire volume of the house in 3 hours. It does not purge heat as quickly as open windows, so when we have cooling breezes we purge the heat. The point is that if you add coolness to the house via AC then t does not escape to the outside easily.
@@theleanarchitect great piece of advice.
25C AC set point! That’s 77F. I’m in TX, I set mine at 22.2C/72F during the day and 20.6C/69F at night.
That's the temperature we choose to set. Other clients go for less, and some choose no AC at all!
Hi, sorry to be that guy, but the ventilated void behind a facade removes negligible heat - this is a common misunderstanding in the industry. It is great at drying the cavity and providing a drainage plane. The colour does affect the local microclimate - walking in front of a dark facade will feel significantly hotter during the day due to infrared heat transfer - and a city full of dark roofs will create more of an urban heat island and cause more cumulative heat damage to PV systems.
I like the internal recirculation on a single AC unit. Americans frequently use central return recirculation units, with the fan coil in the duct system instead, which are better with medium load buildings and climate zones needing more dehumidification.
I agree that the openings at the top and the bottom of the cladding may not ventilate all the heat trapped by the cladding. But it is better than no cavity. In this case we made a conscious decision to go with a dark cladding and the performance of the home doesn't seem to suffer as a result.
@@theleanarchitect Thanks for the reply. I can see how it would be tempting to use a concept like that to counteract the disproportionate emphasis you Ozzies put on cladding colours. But if the effect represents like
The colour does affect the local microclimate, however on the Midnorth Coast of NSW walking next to a white steel wall is much more uncomfortable due to the sun reflecting off it. It's amazing how intense the heat being reflected is. The dark steel reflects the heat too, but not as intensely. I'm sure this would be similar in many parts of WA. If the walls are masonry that would change the scenario. I'm really keen to see studies on the urban heat island effect with a comparison between steel and masonry roof types. I believe there's some study at Newcastle Uni in to this.
@@FrankReifoh that's interesting - what's the misunderstanding around green roofs?
@@theowhite They're expensive to build, heavy, impractical to maintain, and are just worse than using the equivalent price for much more insulation.
You're better off going for a standing seam steel roof, vented mesh to the ridge. It'll last 50 years with next to no maintenance, no problem.
PV systems mount very well to the seams. And you can have it in any colour you like, if you're in an AC climate, by all means make it white!
What is the ceiling panels with the grid of holes? Is this for sound absorption? Make and model is appreciated.
Its 12mm square Acoustic plasterboard. Typically used in commercial projects but very effective in making the room quieter. Especially when concrete floors are combined with high ceilings, you get increased resonance.
We sure got a hot summer this season just gone.
Yes and its going to get hotter!
one good thing about solar panels......they perform well on hot sunny days when running an air con is useful. I commend the use of small practical,sensible windows.....most homes have stupidly large windows for the Australian climate. Dark colorbond colours also fade sooner........any roofer will tell you that. Its stupid.
We have light coloured roof on this house - it is not visible from the street. I must admit that sometimes we cant avoid the dark roof but we take measures to negate its impact on thermal performance, such as ventilating the cavity and provide high density insulation with elevated specific heat capacity.
@@theleanarchitect I completely agree that the thermal affects can be mitigated........the problem is having faded colorbond colors dont hold the intended aesthetic effect for any length of time, by home standards. Homes are not cars.
since you basically have a very light colored roof I would have installed bi facial pv.lifted off of the roof a way so that light reflection can hit the back side of the panels
. and a simple thermal solar to preheat the water.. From my understanding in your part of the world something around 46% of all power is being used to heat water.. Seems like a big load but that is what the installer was saying.
25 degrees C inside? Crikey mate that's way too warm! I'm a 16 degree guy, though anything below 20 would be ok.
Everyone has different comfort requirements! Cooling a house to below 20 degrees when its 40+ outside will use a lot more energy than 24 degrees.
😂 And you step out and die by a heart attack in those 40°C...
Meanwhile he's on wife #3, paying 3 alimonies to keep his AC bill down. 🤣
I was interested until he said the some days it gets over the 40s. Here in Erbil, Iraq, 43 is our summer average while it gets to 48 in some days.
That is warm! Regardless of the climate, a well insulated and sealed home will be easier to cool with AC.
How about the thermal mass?
Thermal Mass is not a consideration of Passive House Software. The thermal stabilising effect of the concrete slab is not quantified but I believe it would be of some benefit in summer. However in winter you pay a heavy penalty for heat losses through the slab to the ground.
@@theleanarchitect that’s surprising, I would have thought in hot climates even more important.
I was an architect, we did a house for an engineer, had solid concrete floors and concrete cored walls, he calculated it would hold six months of heat.
ps. You always insulate below the slab in cold climates
2:19 start
skbidi toilet rizz!! great sigma video
no cap
did you have to watch this video for an investigation aswell?
What r- value is your house insulated to?
Walls are R5, Roof r6.
@@theleanarchitect similar to our house KFW55 in Germany. KFW55 means the house consumes 55% of the energy the given reference house (conventional new build house) consumes. Standards are regulated by the GEG law and other norming rules in Germany: U-values (W/m2 k) of our house: roof 0.17, walls 0.23, floor 0.15, shaded balcony 0.15, windows 0.76, entrance door 0.76. (U=1/R)
I’m guessing you went against the norm and don’t have a permanently open window for the bathroom.
We do have an openable window. However the ventilation system does a great job of drying out the room leaving it odour free with dry towels and surfaces.
Why not have a solar hot water system?
Solar hot water often requires electric or gas booster. A heat pump HWU is more efficient and is powered by our solar PV anyway.
25 is just too hot, 22 max.
Interior thermal comfort level is a personal choice that we discuss with client early in the process. If 22 is the standard required then we specify an appropriate cooling system to achieve that. For us, 25 degrees with 50% RH is more than comfortable.
@@theleanarchitect I agree that 25 is fine. It's all relative. It seems like the western world is obsessed with keeping internal temperatures at a constant 22 deg C. Keeping a house at 22 deg takes a lot of energy and embodied energy.
25 indoors in Perth is a very comfortable temp, with fans running. When I lived there prior to 2000, I would say majority of homes didn’t run aircon, we just slept at the beach when it was too hot!
25° C is ... comfortable !???? That's 77° F - absolutely ABSURD.
Meanwhile he's on wife #3 & pays 3 alimonies to keep his AC bill down. 🤣
25 degrees at 45% relative humidity is well within the human comfort zone. Add air movement from a ceiling fan and it feels more like 23c.
lol. We got an air conditioner