The EPA has stated that the average US home has worse air quality that the air in our most polluted cites. In fact, the air in the average US home is ranked as the 5th worst environmental hazard! One of the reasons is that while an individual item in our home may not cause a significant health risk, the cumulative effect of the thousands of chemicals we bring into our home, many of them untested, has been shown to be a serious risk. Asthma and allergies have steadily risen to epidemic rates since we first began tightening up houses in the 1970’s. Americans spend more time than ever indoors, exacerbating the problem.
The average home in the United States has many small air leaks that can add up to a total size of an open window sash. The problem is that these leaks are not controlled, and frequently deposit fresh air where we don’t need it, i.e. in basements, crawl spaces and attics. This efficiently strips energy from the house and causes uncomfortable home environments, while not really solving the problem of interior air quality.
There are many things a homeowner can do to improve indoor air quality: introduce less chemicals and manufactured goods into the home, make sure the house has positive air pressure relative to an attached garage, install finished goods with low VOC content, and keep chemicals and cleaning agents out of living areas. A good rule of thumb is that if you can smell something, like a plastic toy, it’s off-gassing into your home.
A homeowner can also mechanically ventilate their home through a ducted system. Using devices like a Heat Recovery Ventilator (HRV) or an Energy Recovery Ventilator (ERV), we can provide an adequate amount of air changes to make a home have healthier air quality, while recovering about 70% of the energy that we already paid to condition from the outgoing air. An ERV also balances water vapor content between the incoming and outgoing air streams, helping dehumidify air in the summer and providing moisture in the air in the winter without a separate humidification system.
Better yet, a ducted ventilation system can take stale air from areas that we want to dehumidify, like bathrooms, or areas that tend to have a bit more air pollution, like utility rooms. We can remove pollutant or moisture laden air from these areas and impart fresh air to the areas of our home where we spend the most time, bedrooms and living areas. It’s a great way to keep the air in our homes healthy while saving energy.
As we tighten up buildings for greater energy performance, it is critical to think of the air quality in that building. Almost all buildings and their occupants could benefit from better, more controlled air exchange. In the case of a tight building, however, it is absolutely imperative for the health of the occupants. We at Meadowlark always say; “If your mechanical contractor doesn’t know much about mechanical ventilation equipment or says you don’t need it, you should find another mechanical contractor.” This equipment is a big part of the “V” letter in HVAC, and without it, it just spells HAC.