We all want the air in our homes to be fresh and healthy. By keeping the air free of pollutants - like toxins from some cleaning products, cigarette smoke or off-gassing paints - and by lowering moisture levels that can cause condensation, mold and mildew, we protect our own health and prevent damage to our homes. Proper ventilation is especially important in today's well-insulated, airtight homes.

Unfortunately, the best way to provide proper ventilation isn't as simple as opening your windows. Open windows don't reliably exchange the air in your home with fresh air, and they allow the air that you've paid to heat or cool to escape. This increases your energy bills and can decrease your comfort in the house.

You can achieve effective ventilation in tight, well-insulated homes by using a relatively simple mechanical ventilation system. Mechanical ventilation provides you with a level of control of the flow of fresh air into your home. In fact, all homes built after December 31, 2004, are required by Vermont's Residential Energy Code to have a mechanical ventilation system. Systems range from simple bathroom and kitchen fans that are on automatic controls to whole-house heat-recovery ventilation systems. The amount of energy used by mechanical ventilation systems is far less than the amount that is wasted in a leaky home.

TYPES OF SYSTEMS:

Exhaust-Only Systems

This type of system uses one (or more) exhaust fans to remove air from your living space. This process draws in outdoor air through the leakage points that exist in even the tightest houses. Typically, these systems consist of one or two bathroom exhaust fans. These systems also can consist of a central fan with multiple air intakes in the house.

For optimal results, control your fan(s) with a 24­hour timer that automatically turns on the fan(s) when the house is typically occupied. Quiet, energy-efficient bath fans are widely available in Vermont. Look for fans that are rated at less than two sones the measure of perceived loudness. You can find bath fans that use as few as 18 watts. Today's kitchen range exhaust fans generally are louder, use more power and move more air than the typical bath fan. It is essential that a fan never interfere with the operation of combustion appliances in the home. Fans should exhaust to the outdoors through smooth wall ducts with a minimum of bends, elbows and dips.

Balanced Ventilation Systems

Balanced ventilation systems use exhaust fans to expel indoor air as well as ducts to bring in outdoor air. The most energy-efficient type of balanced ventilation system is one that enables you to retain some of the heat from the air leaving your home. This is called a heat-recovering ventilation (HRV) system. A fully ducted HRV is more costly to install than spot ventilation. However, an HRV is the most effective approach to maintaining good air quality in your home.