How Important is Air Sealing?

Air Sealing a Cold, Drafty House

Air sealing is often one of the most cost-effective measures you can take to make your home more energy efficient and comfortable. Unless your house was built in the last 5 to 10 years, there are probably major air leaks in the living space and in the building shell. Older homes can be extremely leaky, which means the hot or cold air that your heater or air conditioner puts out is mostly blowing out of the house!

Air sealing needs to be evaluated and done by a professional because a home does need some ventilation so that the air isn’t too stagnant. If an older home is sealed too tightly, a mechanical ventilation system — sometimes called an Energy Recovery Ventilator — may need to be added to ensure healthy air quality.

Creating an effective building envelope is about more than just insulation. Some types of insulation that work well in a laboratory do not perform as well in real-world conditions. Wholesale air movement through a building can account for as much as 40% of a building’s thermal loss, and air movement also brings water vapor with it, which can cause damage to the interior of building envelope components.