7 ms·

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

by 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.

tejohnso 5y ago
Insulation under the home, and skirted around it. You may be thinking of a Frost Protected Shallow Foundation[1]. A nice alternative to excavating in order to get below the frost line. I dream of doing this as part of a self built small passive house project. [1]: https://www.greenbuildingsolutions.org/blog/frost-protected-shallow-foundations-saving-energy-and-construction-cost-with-foam-plastic-insulation/ https://www.greenbuildingsolutions.org/blog/frost-protected-...
- swader999 5y ago
  ICF construction where the foundation form is Styrofoam Lego like blocks that concrete is poured into achieves this shallow and in full basement hooded. A lot more homes in Canada use this approach now.
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.
    - empiricus 5y ago
      Not only "philosophical", better insulated houses are also more comfortable.
      - jaclaz 5y ago
        Sure, but not all houses are built for "you" to live in perpetually. You build a house according to the minimal requirements of your local codes/norms. If you next year go to another city you may either sell the house or rent it (at average market value). You build a "passive house". If you next year go to another city you may either sell the house or rent it. Do you believe you can easily get 30% more rent or sale price because it is passive?

by poseva 5y ago

tejohnso 5y ago

Insulation under the home, and skirted around it. You may be thinking of a Frost Protected Shallow Foundation[1]. A nice alternative to excavating in order to get below the frost line. I dream of doing this as part of a self built small passive house project. [1]: https://www.greenbuildingsolutions.org/blog/frost-protected-shallow-foundations-saving-energy-and-construction-cost-with-foam-plastic-insulation/ https://www.greenbuildingsolutions.org/blog/frost-protected-...

swader999 5y ago
ICF construction where the foundation form is Styrofoam Lego like blocks that concrete is poured into achieves this shallow and in full basement hooded. A lot more homes in Canada use this approach now.

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.
  - empiricus 5y ago
    Not only "philosophical", better insulated houses are also more comfortable.
    - jaclaz 5y ago
      Sure, but not all houses are built for "you" to live in perpetually. You build a house according to the minimal requirements of your local codes/norms. If you next year go to another city you may either sell the house or rent it (at average market value). You build a "passive house". If you next year go to another city you may either sell the house or rent it. Do you believe you can easily get 30% more rent or sale price because it is passive?