3 ms·

No thermal mass makes for a horrible passive house.

• hudibras 13y ago
  I'm going to go out on a limb here and say that there's no way this is a passive house. No data (temps or energy consumption) and a concept (lots of insulation and nothing else) that's been tried many times and always fails.
• georgeoliver 13y ago
  They're using the term passive house to mean the 'new wave' passive house, which is more about super-insulating a nearly airtight envelope. Usually a heat-recovery ventilator is added to recover interior heat when cycling in outside air. While thermal mass can be an element in this design it's not a major factor like in a 'passive solar' house.
  • copergi 13y ago
    >which is more about super-insulating a nearly airtight envelope That last part is the problem. Insulation is a huge part in any passive home, but heating the air means keeping things airtight. Which means terrible air quality and living conditions.
    • georgeoliver 13y ago
      You still exchange the air with the outside, you just do it through a heat recovery ventilation system. An introduction: http://en.wikipedia.org/wiki/Passive_house http://en.wikipedia.org/wiki/Passive_house
      • copergi 13y ago
        I am fully aware of what they are, we stopped building them for a reason. They are hell to live in. You get the bare minimum air exchange as required by code. Try being in such a building for a day. Properly constructed passive buildings use thermal mass to maintain comfortable temperatures while allowing proper ventilation.
• bluthru 13y ago
  That depends entirely on the climate. That strategy is most successful in climates with high diurnal swings (desert). You really can't go wrong with insulating the hell out of it elsewhere.
  • copergi 13y ago
    That strategy is successful everywhere. You already insulate anyways, you still need thermal mass. It isn't just about capturing heat during the day to release at night, it is about heating the house instead of the air inside the house. This lets you have proper ventilation.
    • ahoge 13y ago
      But you want the air to be warm, not the walls. Also, passive houses do have proper ventilation: http://en.wikipedia.org/wiki/Passive_house#Airtightness http://en.wikipedia.org/wiki/Passive_house#Airtightness > most of the air exchange with exterior is done by controlled ventilation through an heat-exchanger in order to minimize heat loss (or gain, depending on climate) Without tricks like that, you'll have a hard time getting below 15 kWh/m² per year.
      • copergi 13y ago
        >But you want the air to be warm, not the walls. No, you don't. Heating the structure is far more efficient, allows for proper ventilation, and is far more comfortable for the inhabitants. >Also, passive houses do have proper ventilation: Yes, but this is not a passive house, that's the point. This is just an airtight box of insulation. They have the least amount of ventilation allowed by code. The air quality in such houses is terrible, and they are very uncomfortable to live in. >Without tricks like that, you'll have a hard time getting below 15 kWh/m² per year. You can very easily get to 0 without "tricks" like that. South facing windows + thermal mass.