Passive Homes

Homes that don't use energy to heat and cool the house.:

"Architects in many countries, in attempts to meet new energy efficiency standards like the Leadership in Energy and Environmental Design standard in the United States, are designing homes with better insulation and high-efficiency appliances, as well as tapping into alternative sources of power, like solar panels and wind turbines.

The concept of the passive house, pioneered in this city of 140,000 outside Frankfurt, approaches the challenge from a different angle. Using ultrathick insulation and complex doors and windows, the architect engineers a home encased in an airtight shell, so that barely any heat escapes and barely any cold seeps in. That means a passive house can be warmed not only by the sun, but also by the heat from appliances and even from occupants’ bodies.

And in Germany, passive houses cost only about 5 to 7 percent more to build than conventional houses."

Intriguing. Yes, it gets cold in Germany, but the heat extreme doesn't much go the other way.

While certainly reducing the cost of heating/cooling a house by 95% is inticing, can it work in a place where it can be 100 degrees F in the summer and 0 degrees F in the winter. That is, is a passive home as efficient at keeping cool as it is in keeping warm?