Passive homes are essentially almost airtight. A building constructed using passive house principles is very well-insulated, and is primarily heated by passive solar gain and internal gains from people, pets, or electrical equipment. A 10-mm vapor barrier under the foundation seals to an airtight sheathing on exterior walls and roof. No drafts or moisture penetrate a passive house structure, which is more insulated than a typical code-minimum structure. Passive homes generally have 17 inches of insulation in the same area that code-minimum homes will have 5.5 inches.
The rule of thumb for a passive home is that about 10% will be added to up-front construction costs. Windows are generally heavily insulated as well, triple glazed with argon between. The point of all of the excess wall and window insulation is to minimize heat loss to its extreme, mitigating costs and the need to mechanically bring the house back to zero energy. A specialized ventilation system continuously provides a constant, balanced fresh air supply, while preventing heat loss through that system.
Any additional heat demand is provided through an extremely small source, as any heat generated will be trapped inside. Solar panels on the roof of a passive home are used to heat water, and thermal storage can also be built in by using tile floors, finished concrete slabs, concrete or granite countertops, stone fireplace surrounds, adobe walls or even American Clay.
The super-insulation of a passive home also works in the opposite direction, keeping cool air locked inside during the warmer months. Passive homes are also generally constructed in such a manner that heat gain is minimized through shading and window orientation, thus reducing the necessary cooling load.
There is no limit to the way that passive house principles can be applied. The term itself refers only to energy performance, and not to any particular aesthetic, so a passive house design can range from a contemporary, sleek look to a more traditional structure. If high heating and cooling costs are damaging your calm, consider checking out what it would take to make your home a bit more passive.