9 ms·

I've also built a simple and small (99sqm) PassivHaus in Romania, 5 years ago. Everybody, and I mean everybody from family to friends called me nuts, but I've g

by poseva 5y ago

I've also built a simple and small (99sqm) PassivHaus in Romania, 5 years ago. Everybody, and I mean everybody from family to friends called me nuts, but I've got my payback this winter when the energy prices went trough the roof and I'm just slightly affected. The house is elevated from the ground on 12 concrete columns so that I can insulate under the foundation beams using glass foam, insulation on walls is 30 cm of EPS graphite, underfloor 45 cm EPS and on the roof, 50 cm and the orientation is full on south. For heating it consumes about 1500-2000 kWh per year (December, January, February and a maybe a small part of March) What is the big difference between houses built in North America and Europe is that the European houses are built using concrete and masonry which give them a lot of thermal mass which is crucial to this kind of builds. Have a look here [0], this is the first PassivHaus in my area and is nicely documented. The cost of building a PassivHaus in my country typically goes about 20-25% more than a traditional one. [0]: http://www.sdac.ro/site/archives/category/passivehouse http://www.sdac.ro/site/archives/category/passivehouse

kitd 5y ago
It is interesting that you insulate under the house. One of the more intriguing passive house designs I saw was one where the insulation went down 2-3m into the ground all around the house footprint. This trapped the natural ground heat within that area and fed it upwards into the house. It took about 18 months for the ground to warm up, but once it was there, the ground/house warmed itself with virtually no input. This was in the UK. Colder climates may vary ofc.
- Gravityloss 5y ago
  How would that work? Average temperature in the UK is about 15 C. If your house is at 24 C, this would mean you are constantly leaking heat into the ground from the bottom... I guess one can consider the cube of earth an insulator, it's got a lousy insulation value per meter but it makes it up in thickness.
  - arethuza 5y ago
    Don't think 15C is correct - looks more like 8.5C to 11C in England and 7C to 9C in Scotland. http://projectbritain.com/weather/average.htm http://projectbritain.com/weather/average.htm
    - a_square_peg 5y ago
      You can look up ground temperature for your location here - https://weatherdownloader.oikolab.com/downloader https://weatherdownloader.oikolab.com/downloader. Layer 4 is between 1m to 3m depth beneath the surface.
      - arethuza 5y ago
        Apologies, I didn't appreciate you meant average temperature underground - that is definitely much warmer. We have a ventilation shaft for an old limestone mine near our house and on a cold day the warm air rising from it is very noticeable.
        a_square_peg 5y ago
        I wasn't the commenter so no worries about apologies... just wanted to point out where you can find this information. :)
    - Gravityloss 5y ago
      Sorry, I was wrong indeed, thanks for the correction
- whirlwin 5y ago
  We have an old house from 1988 located in Norway. Walking on the non-insulated wooden floor is very unpleasant. We will refurbish, and insulate under the floor, but it will not be anything near a passive house because of other construction shortcomings
  - deleted 5y ago
    [deleted]
  - ricardobayes 5y ago
    well try non-insulated tiles here in Spain haha. I don't know why houses are built to such a low standard in Spain. Even the UK had better quality constructions when I was there, and that says a lot (single glazed windows, poor insulation, weak plumbing)
    - joking 5y ago
      no harsh climate overall so much less insulation is needed?
      - ricardobayes 5y ago
        Mainland Spain falls into the single digits at night at winter so definitely would need insulation, because there is also no central heating. People resort to heating with their aircons and portable heaters. I'm sad because I expected better infrastructure from 45% income tax at the highest bracket.
        jakub_g 5y ago
        I come from Poland (sub-zero in winter; can be anywhere from -20C to +10C but typically 0-5C), but the winter I lived on the Spanish eastern coast was the coldest in my life: thin walls and windows, stone floor, no heating apart from little portable heaters, 5 degrees and rain outside. Now I live in French southern coast, the buildings are slightly better but still poor. In my place even with all heaters I have on max, I'm nowhere near as comfortable as in properly built and heated apartments in my home place (actually when visiting friends in Poland in winter I'm almost overheating!). Basically half of the year it's quite uncomfortable to stay at home for prolonged time: for ~4 months a year at winter; then again for ~2-3 months at summer (+26C at home with blinds down unless you put aircon on max for hours). Kinda suboptimal for WFH to be honest :)
- leobg 5y ago
  Exactly. Talking about thermal mass! There’s also the movement of underground houses. They use the ground for cooling in summer and for insulation in winter. Also it apparently makes for great noise reduction, in spite of having lots of windows, light and views. See the book “Recovering America: A More Gentle Way to Build”.
  - swader999 5y ago
    Underground houses can be a nightmare dealing with water infiltration, codes and the power of soil.
- poseva 5y ago
  Really interesting. I've read about also "foundation insulation skirt" that allows you to create a warmer earth mass under the house. To be honest this was the biggest "complaint" that others had in regards of how a built the house, the general knowledge says that the earth is warm and you don't need to insulate against it... but the earth is maybe 5-10 degree, of course warmer than outside -5..-10 but still a lot colder than what we want inside the house, 20,21 degree C.
  - jaclaz 5y ago
    That depends on how deep you dig, but of course going deep enough has a cost that may be far greater than the kind of insulation you used. The 20-25% of increase in cost is a good proxi (from my personal experience I would have said 25-30%), but, from an economical standpoint it should be compared with savings over time (in the same region). To give you an example in Italy, last time I calculated it, this 25-30% increase of costs corresponds - loosely - to the costs of heating for 20 years or so (bar the crazy increases in prices of energy that just happened), so it becomes more a "philosophical" choice than anything else to go for passive or almost passive.
    - Sankozi 5y ago
      5% return per year (or more in case of price changes or regulations forcing you to change heating source) does not seem that "philosophical".
      - jaclaz 5y ago
        I don't understand fully your way of reasoning. A normal house costs - say - 200,000 "units" (dollars, euro, whatever). Making it "energy saving" costs an additional 60,000 units. In 20 years time you will be spending 60,000 units (3,000 per year) less for energy costs (and here we are assuming that ventilation and heating/cooling machines in the "better" house have the same maintenance costs than the ones in "normal" house, whilst usually, since they are more complex systems they tend to be more expensive). You essentially have a "break even" point 20 years in the future, from there onwards you start saving money. First thing, you need, now, 260,000 units instead of 200,000 (and not all people may be able to afford this). Then, if, for whatever reasons, you don't use the house at all times in these 20 years, or you need to sell it before that time you are unlikely to fully get the savings. Additionally, in less than 20 years time it is possible that someone comes out with a mega-para-hyper-ultra climatization device that makes yearly energy costs go down by (say) 90%. So, if you want to do the "right thing" from a climate/energy savings point of view, by any means choose to invest in a passive house, but it remains essentially a "philosophical" decision, not an economical one.
- mrweasel 5y ago
  > It is interesting that you insulate under the house. Isn't that pretty normal, I mean maybe not three meters down, but modern foundations are required to be isolated in many places. The legal requirement in Denmark is at least 300mm of isolation under the house.
  - 8fingerlouie 5y ago
    And that's not a new thing either. In my 1970's house we have 150mm insulation under the house from the original build, 150mm in the walls and 200mm on the roof. We added another part to the house a few years ago, and that was 300mm insulation in floor/walls/roof. Since the walls are made of brick with a depth of 7cm, it means the walls are 7+7+30= 44cm thick (plus some "slack") Even my 1980's summerhouse has 100mm insulation in floor/walls/roof.
  - jmrm 5y ago
    That depends of the the place where you live. In middle to the south of Spain, the floor of houses are normally made of marble (or other ceramic material) slabs on top of a little layer of some glue cement, on top of the armoured concrete slab foundation, but on the north is a lot common to have wooden floors with air chamber of a similar size.
  - kitd 5y ago
    It is indeed normal. I mentioned it by way of an intro to the unusual alternative I saw.
- markvdb 5y ago
  > It is interesting that you insulate under the house. Near our place in the countryside, required foundation depth is 1.4m to protect from frost heave. Use an insulated slab and that requirement goes away. The insulation keeps the heat in the ground. It protects the ground under the house from freezing. Nobody cares about regulations here, but they do about getting proper foundations...
  - lelanthran 5y ago
    > The insulation keeps the heat in the ground. It protects the ground under the house from freezing. If it is preventing the ground under the house from freezing, then it is supplying heat to that ground. That's a energy-negative process - some of the heat you generate is used to maintain the warmth of the ground.
    - jounker 5y ago
      Some of your heat is always going into the ground. The insulation prevents it from dissipating into the environment.
    - markvdb 5y ago
      Au contraire, my dear Watson. Without under-slab insulation, the heat emanating from the ground below the house escapes very quickly. This heat we don't generate. It occurs naturally. This is about using the naturally escaping heat to keep the ground under the house from freezing, about raising the frost depth. This technique is especially interesting for holiday homes not permanently heated in northern climates. It's fairly standard in Scandinavia, up and coming in the Baltics, but less known in the US. In the US, it's usually called FPFS or frost protected shallow foundations. [0] [0] https://www.ncei.noaa.gov/products/land-based-station/frost-protected-shallow-foundations https://www.ncei.noaa.gov/products/land-based-station/frost-...
- aaron695 5y ago
- throw0101a 5y ago
  > It is interesting that you insulate under the house. This is part of the building code in many areas: do a search for [under] "slab insulation". * https://www.buildingscience.com/documents/information-sheets/basement-insulation https://www.buildingscience.com/documents/information-sheets... * https://www.finehomebuilding.com/project-guides/insulation/insulating-a-slab-on-grade https://www.finehomebuilding.com/project-guides/insulation/i... It should be at least R-10 (RSI 1.8): * https://www.youtube.com/watch?v=O2dNp9bicSk https://www.youtube.com/watch?v=O2dNp9bicSk * https://www.youtube.com/watch?v=XKp0wRzvR-g https://www.youtube.com/watch?v=XKp0wRzvR-g
- alksjdalkj 5y ago
  > It is interesting that you insulate under the house. I think anyone who's gone camping will appreciate the need for insulation between the ground and whatever you're trying to keep warm - a good sleeping pad is crucial for keeping warm.
- voisin 5y ago
  Do you have a link on this? I’d love to read more about this.
madaxe_again 5y ago
We’ve just built a 45m2 log cabin to passive standards here in Portugal - heavily insulated in walls, floor, roof, lifted off the ground on concrete columns, double glazed, only heat source is a 2.5kw log stove. Everyone here (who all live in uninsulated concrete houses heated by open fireplaces) said we will freeze in the winter, roast in the summer. We situated the house on a north facing slope, to minimise sun exposure in the summer. Means little direct light in the winter, but we think (have yet to experience a summer in it) the balance will be good. As I write this, the stove is out, having burned out overnight, it’s -11 outside, and 25 inside. We are getting through a ridiculously tiny volume of firewood compared to when we were living in a more traditional house for here - less than ⅛ the volume. Insulation works. It’s also cheap. I don’t understand why people would build new structures without it.
- mschuster91 5y ago
  > Insulation works. It’s also cheap. I don’t understand why people would build new structures without it. People are a bit sceptical about many insulation forms... plastic-based stuff is either a fire hazard (see Grenfell Tower) or extremely toxic waste (if it has been treated with fire suppressants), asbestos is completely banned for good reasons, and rock/glass wool can also spread nasty ultra-fine dust.
  - madaxe_again 5y ago
    We’ve purely used rockwool. It’s enclosed within a semipermeable membrane, so no possibility of dust escaping.
- phillc73 5y ago
  It would be very interesting to learn more about this build. Was it something pre-fabricated (I've seen "kit" log homes advertised) or something completely custom?
  - madaxe_again 5y ago
    Pre-fab, although loosely so - about 1000 me-hours to make it into a functional home. I unfortunately can’t recommend the outfit I bought it from, as they screwed up and shipped only part of the order, sent me defective parts (bad and/or incorrectly machined timbers), and had the worst post-sales service I’ve encountered in anything - but there are plenty of companies out there that make decent kit cabins.
jmrm 5y ago
People doesn't give the massive importance the isolation has. Some years ago we remodelled our home and added XPS (Extruded Polystyrene) to insulate the roof of the house. After that we use the AC only three or four days in the year, and before that we had to use it at least a complete summer month. That house is in the south-interior of Spain, so heat is no joke here. If somebody are constructing or remodelling any house I recommend it to add any insulation they can in any shape, in less than five years you'll recover what you spend, and if you add PV panels for electricity or a thermosiphonic system to heat water, you'll recover the investment in about 10 years, with a healthy amount of available health in the devices to continue saving money with a proper maintenance.
- fullstop 5y ago
  > That house is in the south-interior of Spain, so heat is no joke here. I looked up a few areas (Ciudad Real) to see what you meant by heat, but it seems quite similar to a good portion of the northern USA. This makes sense, I suppose, given the similar latitude.
- SOLAR_FIELDS 5y ago
  Insulation is so, so important. I work out of my garage currently and Texas winters get reasonably chilly and of course summers are hot. I'm lucky enough that my garage is actually under a room in my house such that it's insulated (as you imply, roof insulation is one of the most important places to insulate). Even simply adding padded insulation and trim to the exterior door and garage door made it viable enough to stay cool in the summer with zero extra cooling and warm in the winter with a small infrared heater.
- franciscop 5y ago
  What people definitely don't give enough importance is CO2 buildup as well. The more isolated a place is, and smaller, the more environment friendly it is BUT the more likely it is to build up CO2, which leads to headaches. I installed a CO2 meter both at my current home, and at my parent's home for when I go back for Christmas. In my home, it's a fairly big open place so it takes ~2 days of closed windows (0-3C outside) to reach 2000PPM (recommended under 1000, above 2000 starts affecting you, 5000 is the legal limit[1]). However, at my family home where I grew up it's a tiny room and it reaches 3000-4000 just by sleeping there with the window and door closed. So the headaches of "visiting family" might in big part be explained by this. PS, incidentally in Spain! [1] https://www.kane.co.uk/knowledge-centre/what-are-safe-levels-of-co-and-co2-in-rooms https://www.kane.co.uk/knowledge-centre/what-are-safe-levels...
throw0101a 5y ago
> What is the big difference between houses built in North America and Europe is that the European houses are built using concrete and masonry which give them a lot of thermal mass which is crucial to this kind of builds. Here's a 500 sq. m. (5000 sq. ft.) house built with heating equipment that uses 1800W (the equivalent of a hair drier): * https://www.youtube.com/watch?v=_vul4vMFdkA https://www.youtube.com/watch?v=_vul4vMFdkA The same person building his own personal home up to Passive House standards: * https://www.youtube.com/watch?v=mBOvflXoWlw https://www.youtube.com/watch?v=mBOvflXoWlw You do not need concrete† and masonry to make homes efficient. Switching from using 2x4s @16" off centre (OC), to 2x6 @24" OC ("advanced framing") would allow for less wood use, less thermal bridging, and more cavity space for insulation. † It should be noted that concrete creates a lot of CO2 emissions, as does baking bricks. Growing wood on the other hand is a way to sequester carbon.
- poseva 5y ago
  I agree, you do not need concrete and brick but you also need to take into account the local traditions. For ex. building a wood house (framing or CLT) would have cost much more than concrete and bricks and was also much more prone to errors because of the builders lack of experience, at least in my area and country. Recently in Romania it really took of building houses using CLT (cross-laminated-timber) but it costs so much more than a regular brick and mortar house that few people afford it. When -15 outside and 20 degrees inside, my house requires 2000W to keep the balance. This kind of simulations are done using PHPP package from PassivHaus Institut. L.E. What I wanted to point out, thermal mass can have a huge impact on the house energy footprint.. to give you an example, today and tomorrow will be sunny days and this will drive my interior temp to about 23-24 degrees, this heat will heat-up the masonry and slabs and then give me back the heat in the next days when there will be no sun.
  - throw0101a 5y ago
    Wood is fairly inexpensive in North America because there are still many forests (especially in Canada). There is nothing "inherently better" with one material over another for most applications. A good structure mostly depends on proper drainage and cladding to protect against UV rays and bulk water (precipitation), good air tightness (with mechanical ventilation for filtered, tempered fresh air), and high insulation. * https://www.buildingscience.com/documents/insights/bsi-001-the-perfect-wall https://www.buildingscience.com/documents/insights/bsi-001-t...
bserge 5y ago
goodpoint 5y ago
> small (99sqm) Is that correct? 99 is not small at all.
- poseva 5y ago
  Small in comparison with a typical single family homes that goes >150 sqm in my area. I completely agree with you, 99 sqm is more than enough for a 4 people family.
  - em-bee 5y ago
    it depends on how you can use the space. 4 people can mean three bedrooms. in some parts of asia the average 3-bedroom flat is 150m². a few years ago i did a search in a european city and likewise was unable to find 3-bedroom apartments with less than 120m². 4 was 150m² minimum. the problem is huge living rooms that can't be divided up and repurposed to make living space for more people. work from home doesn't need a lot of space, but with young kids i absolutely need a lockable room. my current office room is 5m². plenty of space. but finding an apartment with that kind of room is rare.
    - rsynnott 5y ago
      > I did a search in a european city and likewise was unable to find 3-bedroom apartments with less than 120m². 4 was 150m² minimum. You simply chose the wrong European city :) Try Dublin, the city of 70sqm 3 bed apartments (in fairness, these aren't allowed under current planning regs, but there are quite a lot of old ones).
    - kwhitefoot 5y ago
      The average size of homes in the UK is under 80 m2. See https://shrinkthatfootprint.com/how-big-is-a-house https://shrinkthatfootprint.com/how-big-is-a-house
- deleted 5y ago
  [deleted]
k__ 5y ago
A friend of mine, who is an architect, told me the technology is ripe to build houses that produce even more energy than they consume, but people simply don't want to live in them. The article talks about "using the best windows", the problem my friend saw in many of such houses was simply that the dwellers would either open the windows too often, losing all the heat, or feel miserable because they weren't allowed to open the windows. A pure psychological effect of course, even with the best ventilation people still had the urge to open a window and felt bad if they couldn't.
- throwaway984393 5y ago
  I recently lived in a house with no external ventilation in one big room. Huuuge windows looking out onto a huge backyard full of trees and flowers. Yeah I missed being able to open the window and hear the birds. But then when lawnmowers started buzzing and dogs started barking, and later when winter hit, I was quite glad for the peace and quiet and no need to open them!
  - pnutjam 5y ago
    I never open my windows unless I'm trying to air out something.
- changoplatanero 5y ago
  how do you ventilate without losing all the heat?
  - jhgb 5y ago
    Recuperator ventilation, presumably?
  - CrazyStat 5y ago
    Heat recovery ventilation [1] can bring in fresh air and output old air while recovering the vast majority of the heat. [1] https://en.wikipedia.org/wiki/Heat_recovery_ventilation https://en.wikipedia.org/wiki/Heat_recovery_ventilation
mariushn 5y ago
Salut! Could you please share more info / photos / tips, besides the sdac.ro link? How high is the elevation? What kind of heating do you use? How do you refresh the air? (opening the windows or heat recovery system) Thanks
AtlasBarfed 5y ago
So with home solar panels and storage getting cheaper and cheaper and better and better, where is the optimization point of investing in better insulation vs just buying more solar panels? Especially if the solar panels may produce profit on sunny mild days about 40-50% of the year if there is reverse metering and the like?
- maxwell86 5y ago
  Insulation beats solar panels. It’s not only much cheaper to get, but also to maintain. The body heat of a family of 4 is enough to heat a well insulated house. Solar panels are there to supply electricity for use. The last step of passive houses are zero-energy houses, which means that they don’t get electricity from the grid.

by poseva 5y ago

kitd 5y ago

It is interesting that you insulate under the house. One of the more intriguing passive house designs I saw was one where the insulation went down 2-3m into the ground all around the house footprint. This trapped the natural ground heat within that area and fed it upwards into the house. It took about 18 months for the ground to warm up, but once it was there, the ground/house warmed itself with virtually no input. This was in the UK. Colder climates may vary ofc.

Gravityloss 5y ago
How would that work? Average temperature in the UK is about 15 C. If your house is at 24 C, this would mean you are constantly leaking heat into the ground from the bottom... I guess one can consider the cube of earth an insulator, it's got a lousy insulation value per meter but it makes it up in thickness.
- arethuza 5y ago
  Don't think 15C is correct - looks more like 8.5C to 11C in England and 7C to 9C in Scotland. http://projectbritain.com/weather/average.htm http://projectbritain.com/weather/average.htm
  - a_square_peg 5y ago
    You can look up ground temperature for your location here - https://weatherdownloader.oikolab.com/downloader https://weatherdownloader.oikolab.com/downloader. Layer 4 is between 1m to 3m depth beneath the surface.
    - arethuza 5y ago
      Apologies, I didn't appreciate you meant average temperature underground - that is definitely much warmer. We have a ventilation shaft for an old limestone mine near our house and on a cold day the warm air rising from it is very noticeable.
      - a_square_peg 5y ago
        I wasn't the commenter so no worries about apologies... just wanted to point out where you can find this information. :)
  - Gravityloss 5y ago
    Sorry, I was wrong indeed, thanks for the correction
whirlwin 5y ago
We have an old house from 1988 located in Norway. Walking on the non-insulated wooden floor is very unpleasant. We will refurbish, and insulate under the floor, but it will not be anything near a passive house because of other construction shortcomings
- deleted 5y ago
  [deleted]
- ricardobayes 5y ago
  well try non-insulated tiles here in Spain haha. I don't know why houses are built to such a low standard in Spain. Even the UK had better quality constructions when I was there, and that says a lot (single glazed windows, poor insulation, weak plumbing)
  - joking 5y ago
    no harsh climate overall so much less insulation is needed?
    - ricardobayes 5y ago
      Mainland Spain falls into the single digits at night at winter so definitely would need insulation, because there is also no central heating. People resort to heating with their aircons and portable heaters. I'm sad because I expected better infrastructure from 45% income tax at the highest bracket.
      - jakub_g 5y ago
        I come from Poland (sub-zero in winter; can be anywhere from -20C to +10C but typically 0-5C), but the winter I lived on the Spanish eastern coast was the coldest in my life: thin walls and windows, stone floor, no heating apart from little portable heaters, 5 degrees and rain outside. Now I live in French southern coast, the buildings are slightly better but still poor. In my place even with all heaters I have on max, I'm nowhere near as comfortable as in properly built and heated apartments in my home place (actually when visiting friends in Poland in winter I'm almost overheating!). Basically half of the year it's quite uncomfortable to stay at home for prolonged time: for ~4 months a year at winter; then again for ~2-3 months at summer (+26C at home with blinds down unless you put aircon on max for hours). Kinda suboptimal for WFH to be honest :)
leobg 5y ago
Exactly. Talking about thermal mass! There’s also the movement of underground houses. They use the ground for cooling in summer and for insulation in winter. Also it apparently makes for great noise reduction, in spite of having lots of windows, light and views. See the book “Recovering America: A More Gentle Way to Build”.
- swader999 5y ago
  Underground houses can be a nightmare dealing with water infiltration, codes and the power of soil.
poseva 5y ago
Really interesting. I've read about also "foundation insulation skirt" that allows you to create a warmer earth mass under the house. To be honest this was the biggest "complaint" that others had in regards of how a built the house, the general knowledge says that the earth is warm and you don't need to insulate against it... but the earth is maybe 5-10 degree, of course warmer than outside -5..-10 but still a lot colder than what we want inside the house, 20,21 degree C.
- jaclaz 5y ago
  That depends on how deep you dig, but of course going deep enough has a cost that may be far greater than the kind of insulation you used. The 20-25% of increase in cost is a good proxi (from my personal experience I would have said 25-30%), but, from an economical standpoint it should be compared with savings over time (in the same region). To give you an example in Italy, last time I calculated it, this 25-30% increase of costs corresponds - loosely - to the costs of heating for 20 years or so (bar the crazy increases in prices of energy that just happened), so it becomes more a "philosophical" choice than anything else to go for passive or almost passive.
  - Sankozi 5y ago
    5% return per year (or more in case of price changes or regulations forcing you to change heating source) does not seem that "philosophical".
    - jaclaz 5y ago
      I don't understand fully your way of reasoning. A normal house costs - say - 200,000 "units" (dollars, euro, whatever). Making it "energy saving" costs an additional 60,000 units. In 20 years time you will be spending 60,000 units (3,000 per year) less for energy costs (and here we are assuming that ventilation and heating/cooling machines in the "better" house have the same maintenance costs than the ones in "normal" house, whilst usually, since they are more complex systems they tend to be more expensive). You essentially have a "break even" point 20 years in the future, from there onwards you start saving money. First thing, you need, now, 260,000 units instead of 200,000 (and not all people may be able to afford this). Then, if, for whatever reasons, you don't use the house at all times in these 20 years, or you need to sell it before that time you are unlikely to fully get the savings. Additionally, in less than 20 years time it is possible that someone comes out with a mega-para-hyper-ultra climatization device that makes yearly energy costs go down by (say) 90%. So, if you want to do the "right thing" from a climate/energy savings point of view, by any means choose to invest in a passive house, but it remains essentially a "philosophical" decision, not an economical one.
mrweasel 5y ago
> It is interesting that you insulate under the house. Isn't that pretty normal, I mean maybe not three meters down, but modern foundations are required to be isolated in many places. The legal requirement in Denmark is at least 300mm of isolation under the house.
- 8fingerlouie 5y ago
  And that's not a new thing either. In my 1970's house we have 150mm insulation under the house from the original build, 150mm in the walls and 200mm on the roof. We added another part to the house a few years ago, and that was 300mm insulation in floor/walls/roof. Since the walls are made of brick with a depth of 7cm, it means the walls are 7+7+30= 44cm thick (plus some "slack") Even my 1980's summerhouse has 100mm insulation in floor/walls/roof.
- jmrm 5y ago
  That depends of the the place where you live. In middle to the south of Spain, the floor of houses are normally made of marble (or other ceramic material) slabs on top of a little layer of some glue cement, on top of the armoured concrete slab foundation, but on the north is a lot common to have wooden floors with air chamber of a similar size.
- kitd 5y ago
  It is indeed normal. I mentioned it by way of an intro to the unusual alternative I saw.
markvdb 5y ago
> It is interesting that you insulate under the house. Near our place in the countryside, required foundation depth is 1.4m to protect from frost heave. Use an insulated slab and that requirement goes away. The insulation keeps the heat in the ground. It protects the ground under the house from freezing. Nobody cares about regulations here, but they do about getting proper foundations...
- lelanthran 5y ago
  > The insulation keeps the heat in the ground. It protects the ground under the house from freezing. If it is preventing the ground under the house from freezing, then it is supplying heat to that ground. That's a energy-negative process - some of the heat you generate is used to maintain the warmth of the ground.
  - jounker 5y ago
    Some of your heat is always going into the ground. The insulation prevents it from dissipating into the environment.
  - markvdb 5y ago
    Au contraire, my dear Watson. Without under-slab insulation, the heat emanating from the ground below the house escapes very quickly. This heat we don't generate. It occurs naturally. This is about using the naturally escaping heat to keep the ground under the house from freezing, about raising the frost depth. This technique is especially interesting for holiday homes not permanently heated in northern climates. It's fairly standard in Scandinavia, up and coming in the Baltics, but less known in the US. In the US, it's usually called FPFS or frost protected shallow foundations. [0] [0] https://www.ncei.noaa.gov/products/land-based-station/frost-protected-shallow-foundations https://www.ncei.noaa.gov/products/land-based-station/frost-...
aaron695 5y ago
throw0101a 5y ago
> It is interesting that you insulate under the house. This is part of the building code in many areas: do a search for [under] "slab insulation". * https://www.buildingscience.com/documents/information-sheets/basement-insulation https://www.buildingscience.com/documents/information-sheets... * https://www.finehomebuilding.com/project-guides/insulation/insulating-a-slab-on-grade https://www.finehomebuilding.com/project-guides/insulation/i... It should be at least R-10 (RSI 1.8): * https://www.youtube.com/watch?v=O2dNp9bicSk https://www.youtube.com/watch?v=O2dNp9bicSk * https://www.youtube.com/watch?v=XKp0wRzvR-g https://www.youtube.com/watch?v=XKp0wRzvR-g
alksjdalkj 5y ago
> It is interesting that you insulate under the house. I think anyone who's gone camping will appreciate the need for insulation between the ground and whatever you're trying to keep warm - a good sleeping pad is crucial for keeping warm.
voisin 5y ago
Do you have a link on this? I’d love to read more about this.

madaxe_again 5y ago

We’ve just built a 45m2 log cabin to passive standards here in Portugal - heavily insulated in walls, floor, roof, lifted off the ground on concrete columns, double glazed, only heat source is a 2.5kw log stove. Everyone here (who all live in uninsulated concrete houses heated by open fireplaces) said we will freeze in the winter, roast in the summer. We situated the house on a north facing slope, to minimise sun exposure in the summer. Means little direct light in the winter, but we think (have yet to experience a summer in it) the balance will be good. As I write this, the stove is out, having burned out overnight, it’s -11 outside, and 25 inside. We are getting through a ridiculously tiny volume of firewood compared to when we were living in a more traditional house for here - less than ⅛ the volume. Insulation works. It’s also cheap. I don’t understand why people would build new structures without it.

mschuster91 5y ago
> Insulation works. It’s also cheap. I don’t understand why people would build new structures without it. People are a bit sceptical about many insulation forms... plastic-based stuff is either a fire hazard (see Grenfell Tower) or extremely toxic waste (if it has been treated with fire suppressants), asbestos is completely banned for good reasons, and rock/glass wool can also spread nasty ultra-fine dust.
- madaxe_again 5y ago
  We’ve purely used rockwool. It’s enclosed within a semipermeable membrane, so no possibility of dust escaping.
phillc73 5y ago
It would be very interesting to learn more about this build. Was it something pre-fabricated (I've seen "kit" log homes advertised) or something completely custom?
- madaxe_again 5y ago
  Pre-fab, although loosely so - about 1000 me-hours to make it into a functional home. I unfortunately can’t recommend the outfit I bought it from, as they screwed up and shipped only part of the order, sent me defective parts (bad and/or incorrectly machined timbers), and had the worst post-sales service I’ve encountered in anything - but there are plenty of companies out there that make decent kit cabins.

jmrm 5y ago

People doesn't give the massive importance the isolation has. Some years ago we remodelled our home and added XPS (Extruded Polystyrene) to insulate the roof of the house. After that we use the AC only three or four days in the year, and before that we had to use it at least a complete summer month. That house is in the south-interior of Spain, so heat is no joke here. If somebody are constructing or remodelling any house I recommend it to add any insulation they can in any shape, in less than five years you'll recover what you spend, and if you add PV panels for electricity or a thermosiphonic system to heat water, you'll recover the investment in about 10 years, with a healthy amount of available health in the devices to continue saving money with a proper maintenance.

fullstop 5y ago
> That house is in the south-interior of Spain, so heat is no joke here. I looked up a few areas (Ciudad Real) to see what you meant by heat, but it seems quite similar to a good portion of the northern USA. This makes sense, I suppose, given the similar latitude.
SOLAR_FIELDS 5y ago
Insulation is so, so important. I work out of my garage currently and Texas winters get reasonably chilly and of course summers are hot. I'm lucky enough that my garage is actually under a room in my house such that it's insulated (as you imply, roof insulation is one of the most important places to insulate). Even simply adding padded insulation and trim to the exterior door and garage door made it viable enough to stay cool in the summer with zero extra cooling and warm in the winter with a small infrared heater.
franciscop 5y ago
What people definitely don't give enough importance is CO2 buildup as well. The more isolated a place is, and smaller, the more environment friendly it is BUT the more likely it is to build up CO2, which leads to headaches. I installed a CO2 meter both at my current home, and at my parent's home for when I go back for Christmas. In my home, it's a fairly big open place so it takes ~2 days of closed windows (0-3C outside) to reach 2000PPM (recommended under 1000, above 2000 starts affecting you, 5000 is the legal limit[1]). However, at my family home where I grew up it's a tiny room and it reaches 3000-4000 just by sleeping there with the window and door closed. So the headaches of "visiting family" might in big part be explained by this. PS, incidentally in Spain! [1] https://www.kane.co.uk/knowledge-centre/what-are-safe-levels-of-co-and-co2-in-rooms https://www.kane.co.uk/knowledge-centre/what-are-safe-levels...

throw0101a 5y ago

> What is the big difference between houses built in North America and Europe is that the European houses are built using concrete and masonry which give them a lot of thermal mass which is crucial to this kind of builds. Here's a 500 sq. m. (5000 sq. ft.) house built with heating equipment that uses 1800W (the equivalent of a hair drier): * https://www.youtube.com/watch?v=_vul4vMFdkA https://www.youtube.com/watch?v=_vul4vMFdkA The same person building his own personal home up to Passive House standards: * https://www.youtube.com/watch?v=mBOvflXoWlw https://www.youtube.com/watch?v=mBOvflXoWlw You do not need concrete† and masonry to make homes efficient. Switching from using 2x4s @16" off centre (OC), to 2x6 @24" OC ("advanced framing") would allow for less wood use, less thermal bridging, and more cavity space for insulation. † It should be noted that concrete creates a lot of CO2 emissions, as does baking bricks. Growing wood on the other hand is a way to sequester carbon.

poseva 5y ago
I agree, you do not need concrete and brick but you also need to take into account the local traditions. For ex. building a wood house (framing or CLT) would have cost much more than concrete and bricks and was also much more prone to errors because of the builders lack of experience, at least in my area and country. Recently in Romania it really took of building houses using CLT (cross-laminated-timber) but it costs so much more than a regular brick and mortar house that few people afford it. When -15 outside and 20 degrees inside, my house requires 2000W to keep the balance. This kind of simulations are done using PHPP package from PassivHaus Institut. L.E. What I wanted to point out, thermal mass can have a huge impact on the house energy footprint.. to give you an example, today and tomorrow will be sunny days and this will drive my interior temp to about 23-24 degrees, this heat will heat-up the masonry and slabs and then give me back the heat in the next days when there will be no sun.
- throw0101a 5y ago
  Wood is fairly inexpensive in North America because there are still many forests (especially in Canada). There is nothing "inherently better" with one material over another for most applications. A good structure mostly depends on proper drainage and cladding to protect against UV rays and bulk water (precipitation), good air tightness (with mechanical ventilation for filtered, tempered fresh air), and high insulation. * https://www.buildingscience.com/documents/insights/bsi-001-the-perfect-wall https://www.buildingscience.com/documents/insights/bsi-001-t...

bserge 5y ago

goodpoint 5y ago

> small (99sqm) Is that correct? 99 is not small at all.

poseva 5y ago
Small in comparison with a typical single family homes that goes >150 sqm in my area. I completely agree with you, 99 sqm is more than enough for a 4 people family.
- em-bee 5y ago
  it depends on how you can use the space. 4 people can mean three bedrooms. in some parts of asia the average 3-bedroom flat is 150m². a few years ago i did a search in a european city and likewise was unable to find 3-bedroom apartments with less than 120m². 4 was 150m² minimum. the problem is huge living rooms that can't be divided up and repurposed to make living space for more people. work from home doesn't need a lot of space, but with young kids i absolutely need a lockable room. my current office room is 5m². plenty of space. but finding an apartment with that kind of room is rare.
  - rsynnott 5y ago
    > I did a search in a european city and likewise was unable to find 3-bedroom apartments with less than 120m². 4 was 150m² minimum. You simply chose the wrong European city :) Try Dublin, the city of 70sqm 3 bed apartments (in fairness, these aren't allowed under current planning regs, but there are quite a lot of old ones).
  - kwhitefoot 5y ago
    The average size of homes in the UK is under 80 m2. See https://shrinkthatfootprint.com/how-big-is-a-house https://shrinkthatfootprint.com/how-big-is-a-house
deleted 5y ago
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k__ 5y ago

A friend of mine, who is an architect, told me the technology is ripe to build houses that produce even more energy than they consume, but people simply don't want to live in them. The article talks about "using the best windows", the problem my friend saw in many of such houses was simply that the dwellers would either open the windows too often, losing all the heat, or feel miserable because they weren't allowed to open the windows. A pure psychological effect of course, even with the best ventilation people still had the urge to open a window and felt bad if they couldn't.

throwaway984393 5y ago
I recently lived in a house with no external ventilation in one big room. Huuuge windows looking out onto a huge backyard full of trees and flowers. Yeah I missed being able to open the window and hear the birds. But then when lawnmowers started buzzing and dogs started barking, and later when winter hit, I was quite glad for the peace and quiet and no need to open them!
- pnutjam 5y ago
  I never open my windows unless I'm trying to air out something.
changoplatanero 5y ago
how do you ventilate without losing all the heat?
- jhgb 5y ago
  Recuperator ventilation, presumably?
- CrazyStat 5y ago
  Heat recovery ventilation [1] can bring in fresh air and output old air while recovering the vast majority of the heat. [1] https://en.wikipedia.org/wiki/Heat_recovery_ventilation https://en.wikipedia.org/wiki/Heat_recovery_ventilation

mariushn 5y ago

Salut! Could you please share more info / photos / tips, besides the sdac.ro link? How high is the elevation? What kind of heating do you use? How do you refresh the air? (opening the windows or heat recovery system) Thanks

AtlasBarfed 5y ago

So with home solar panels and storage getting cheaper and cheaper and better and better, where is the optimization point of investing in better insulation vs just buying more solar panels? Especially if the solar panels may produce profit on sunny mild days about 40-50% of the year if there is reverse metering and the like?

maxwell86 5y ago
Insulation beats solar panels. It’s not only much cheaper to get, but also to maintain. The body heat of a family of 4 is enough to heat a well insulated house. Solar panels are there to supply electricity for use. The last step of passive houses are zero-energy houses, which means that they don’t get electricity from the grid.