Saturday, November 19, 2005
If you've ever examined a sliver of sunlight filtering through your home's window, then you've surely seen tiny specks of dust dancing on the air.
These minute airborne particles are a mix of dust, pollen, pet dander, lint and plant and mold spores and are present in even the cleanest of homes, but for some people, they can trigger allergies and asthma.
There are a variety of products on the market that promise to purify indoor air and rid it of these types of airborne particles.
According to the American Lung Association, some of these products make a difference, while others do little to improve indoor air quality.
Here's an overview of what works and what doesn't.
FILTERS
Step into a home improvement center, and you're bound to see a plethora of 1-inch-thick air filters designed to fit a home's heating, air conditioning or ventilation system.
Some filters successfully remove particles from the air, while others do not.
UFlat fiberglass filters: These filters are typically designed as furnace filters and are made of spun fiberglass. Their primary function is to protect the furnace fan and minimize the amount of dust that settles on heating and cooling coils. These types of filters do little to remove airborne particles or improve indoor air quality.
UWashable and reusable filters: These filters do little to capture small airborne particles. Worse, if they're not completely clean after washing, they can actual create airflow restrictions.
UNonelectrostatic pleated filters: Featuring folds or pleats, these filters are an improvement over the standard flat filter and are usually better at removing airborne particles than fiberglass or washable filters.
UElectrostatic pleated or high efficiency filters: These filters have an electrostatic charge that captures small particles and allergens such as dust, pollen, mold and pet dander. These types of filters do the best job of removing airborne particles and can be 30 times more effective than flat filters.
UHigh Efficiency Particulate Air Filters: Also known as HEPA filters, these large filters are the Cadillac of air filters and are designed to remove 99.97 percent of particles 0.3 microns and larger. However, HEPA filters are not designed to fit most furnaces. They usually need a separate fan and filter system. Watch out for misleading "HEPA-like" labeled filters. Genuine HEPA air cleaning systems need a powerful motor to move air through their thick multilayers.
UAnother tip: Some furnace filters feature "antimicrobial" additives. Since furnace filters are dry, nonorganic surfaces with very little food or water for microbes to feed on, these additives do little to improve indoor air.
ELECTRONIC AIR CLEANERS
Do electronic air cleaners really work? Some do and some don't, according to the American Lung Association.
UWhole-house electronic air cleaners: These permanent filters are installed in the ductwork of central heating and cooling systems and rely on an electrical field to trap charged particles. These types of air cleaners do a good job of clearing the air of indoor pollution particles, but to be effective, they must be cleaned at regular intervals.
UPortable tabletop air cleaners: These small tabletop air-cleaning units generally have a limited airflow and inefficient panel filters and are ineffective in purifying the air of the entire room.
UPortable room air cleaners: Since they are larger than portable tabletop units and have more effective filters and collecting plates, portable room air cleaning units do a better job in purifying the air of a room.
UAdditional tip: Good, old-fashioned fresh air can help create and maintain a less polluted indoor environment.
Although a snug, well-insulated home is a must, home's can also be "too tight."
You and your house can benefit from a little natural airflow through cracks and open windows.
This type of natural ventilation will also help preserve a home's structure by preventing moisture problems.