A well sealed house typically needs controlled ventilation to ensure good air quality.
A house works as a complete system and if you are considering increasing your insulation, sealing air leaks, or replacing leaky windows and doors, you should also consider the impact it will have on air flow and ventilation. A well sealed house typically needs controlled ventilation to ensure good air quality. There are many areas of a house that require ventilation, including fans to control moisture in the bathroom and a range hood over your stove in the kitchen.
If you have to replace a ventilation fan, consider purchasing an ENERGY STAR model, which uses about 65% less energy than a standard model. There are also ENERGY STAR-qualified ceiling fans, which circulate air 20% more efficiently.
Heat Recovery Ventilators (HRVs)
Some ventilation systems simply exhaust the warm air from inside the home, and take in cold air from outside and circulate it. Having to warm this cold air can place additional demand on your heating system and can lower the gains you made from insulating and sealing air leaks.
However, there is a technology to avoid this called a "heat recovery ventilator." This system transfers heat from the warm exhaust air that is exiting the house, to the cold air that is coming in, which reduces pressure on the heating system. Typically, a heat recovery ventilator is able to recover 70 to 80% of the heat from the exhaust air and transfer it to the incoming air. This dramatically reduces the energy required to heat your home.