As homes become more efficient, proper ventilation is increasingly important. Green building techniques and tighter building envelopes require proper air exchange to manage indoor air quality.
Why the increase in air quality problems? Older homes were “naturally” ventilated through uncontrolled air leaks and building products were manufactured without flame retardants and other additives. Today’s building products have more additives and homes are built tight compared to older homes. Tight building envelopes combined with the additives in construction materials require a controlled ventilation system to maintain optimal air quality and a home’s energy efficiency.
There are many factors that influence the type of ventilation system that is appropriate for a home. These can include local code requirements, building size, types of appliances, etc.
The four most common ventilation systems are:
Exhaust Only – This type of system uses a small exhaust fan that is commonly placed in a kitchen or bathroom. This is programmed to run either continuously or intermittently to pull out stale air and moisture. These systems are low cost and quite easy to install.
Supply Only – A supply-only system includes a fan that brings fresh air into the home. The air escape happens through the natural air leaks in the home. A filter can be added to trap pollen and other outdoor air pollutants before they enter the home. A dehumidifier can be added inside the home to control indoor humidity levels.
Balanced – A balanced system includes both exhaust and supply, controlling ventilation at both ends. This system includes separate fans to manage air supply and air exhaust. Overall, this is a better ventilation system than exhaust only or supply-only system.
Balanced With Heat Recovery – Like the balanced system, a balanced system with heat recovery will condition the incoming air prior to entering the home. This is a great system for cold climates, preventing cold air from being drawn into the home during winter.