Air pollution is the most serious long-term health hazard in the indoor environment.  Carbon Monoxide, Nitrogen Oxides, Volatile Organic Compounds, Radon and fine dust particles pose serious health hazards to occupants of any home.  A home energy rating is an excellent tool to determine if your home is a healthy environment.  An integral part of any energy rating is determining the proper fresh air supply and minimum ventilation requirements for your home.

A home can be "too tight" in the sense that it does not allow the old, stale air to be replaced with fresh air.  Over time, moisture, odors, and pollutants build up inside the home to the point the air is unhealthy.  A common rule of thumb is the entire home air supply should be replaced every three hours.  Today, homes are built extremely "tight."  Air barriers, moisture and radiant barriers, result in homes that prevent air infiltration.  Decreasing air infiltration is a positive for energy efficiency but it could be a huge negative for healthy air quality.  There is an expression used by builders, "tight is right."  Modern building methods and materials have made homes so tight, sometimes it is necessary to introduce outside air using power exhaust and supply fans - an increased cost that negates the efficiency of building a "tight" home in the first place.

Comfort is another consideration.  We heat and cool our homes in order to provide a comfortable environment for ourselves and our family.  We depend on our furnace and air conditioning equipment to evenly distribute comfortable air throughout the home.  But sometimes that distribution isn't so even, leaving some areas of the home uncomfortably cool or unbearably hot.  In many cases the problem is a lack of supply/return balance.  Adding insulation, increasing capacity, adding radiant barriers, and replacing windows may be expensive and ineffective solutions to the wrong problem.  Or they may be appropriate.  The point is you can guess at the problem, or you can test your home and find out for sure.

Accidental air leakage through the building envelope accounts for between 25 percent and 40 percent of the energy used for heating and cooling in a typical residence. Many new homes are being air sealed to reduce this excess energy use.   Accidental ventilation is unreliable because it is dependent on a pressure difference between indoor and outdoor spaces caused by temperature or wind variations. Too much fresh air often enters a house during cold weather causing uncomfortable drafts and high heating bills and uncomfortably dry conditions.   Not enough fresh air may enter during mild weather which can lead to poor indoor air quality. Where tighter construction reduces air leakage and accidental ventilation, active ventilation systems may be needed to provide fresh air.

There are some significant advantages of mechanical ventilation. A controlled and consistant indoor environment is the chief advantage. Moisture, odors, and pollutants are removed continuously, regardless of weather conditions. High indoor air quality is maintained due to the constant circulation of outdoor air.

Take the first step to making your home more healthy and comfortable.