[wheresmyusern]

you dont seem to have read the article. passive houses generally have very good insulation, very air-tight envelopes and a system that is called heat recovery ventilation.

insulation and air tightness afford the house the property of staying the same temperature on the inside regardless of the temperature on the outside, more or less. if its too hot or too cold outside, this is something you always want. heat recovery ventilation gives the house the ability to move old air out of the building and new air into the building while not changing the temperature of the air inside, more or less. this is why its called heat recovery (also it could also be called cold recovery). this solves humidity problems.

the end result is a house that will tend to stay the same temperature, whether that is hot or cold. in an ideal model of this kind of house, you can see that heating and cooling costs are reduced to almost nothing because you simply choose a temperature that you like and simply never think about it again. this is the origin of the "passive" component of "passive house." with a passive house, you simply dont need a large hvac system. and there is nothing stopping you from adding a modest solar system to your passive house to get to net zero -- it is done quite frequently.

[oxryly1]

> insulation and air tightness afford the house the property of staying the same temperature on the inside regardless of the temperature on the outside, more or less.

But how is that initial temperature determined? If the house is built in a area during a time of year where the average air temperature is about 85F, then will the house always be too hot? How does it get cool (or hot) in first place?

[wheresmyusern]

the initial temperature, in that ideal system, is determined by deliberately making it hot or cold with a small sized air conditioner or heater. so in the ideal system you heat or cool once and then never again.