A home built to Passive House standards always has operable windows. You can open the windows anytime you like to get a fresh breeze. When the weather is inclement or it’s too noisy outside, you have the choice of closing the windows and getting filtered fresh air through a heat recovery ventilator (HRV).
Offices built to Passive House standards provide filtered fresh air through an HRV. While operable windows are typically not required for offices in the US, they can provide a pleasant alternative to mechanical ventilation when the outdoor conditions are right.
Reduce allergens such as pollen and dander with a central air filtration system. Make filtration energy efficient by combining it with the heat recovery ventilation system.
Mold and Mildew Prevention
Mold and mildew are fungi that can cause building deterioration, allergic reactions, and other health problems. Filtration of the intake air provides the best means of preventing airborne spores from entering a building. See Indoor Mold Growth. According to the EPA humidity levels between 30% and 60% are sufficient to reduce mold growth. Dust can act as a nutrient base for mold, so regular cleaning and providing filtered fresh air are important. Finally, moisture from condensation helps mold grow. Avoiding thermal bridges and providing sufficient insulation can prevent condensation.