Today's homes are more tightly constructed than ever. This means less airborne dirt and dust can infiltrate the home from outside.

However, it also means dirt, dust, grease, pollen, spores and other airborne particles that already exist in a home can't get out and are re-circulated over and over again.

To remove these particles, that can cause unnecessary physical discomfort as well as damage furnishings, more and more homeowners are turning to high efficiency electronic air cleaners.

The reason: electronic air cleaners can remove up to 95% of these undesirable airborne particles. A typical disposable furnace filter only removes 10 to 15% of the contaminants.

According to the Trane Home Comfort Institute, electronic air cleaners are usually installed in the duct carrying air back to the furnace.

Operation of the unit is fairly simple. First, air passes through a mesh-type filter that catches large airborne particles. Smaller particles that get through the filter pass through an ionizing section where they receive an electrical charge.

These charged particles then pass through plates which have an opposite charge that attracts the particles like a magnet. The particles remain on the plates until the air cleaner elements are washed. The result is a healthier, cleaner indoor environment.

The environment is healthier because electronic air cleaners remove much of the dust, pollen, mold spores and other microscopic irritants that make life miserable for people with allergies and respiratory problems. These same contaminants can also harbor harmful bacteria and viruses.

The home is cleaner because electronic air cleaners remove the dust particles that normally settle on walls, floors, drapes, upholstery and other furnishings. This allows homeowners to spend less time and money on routine house cleaning tasks. Electronic air cleaners also remove dust particles that can damage home entertainment equipment and computer hardware.

Electronic air cleaners do all this using only about the same amount of electricity as a 40-watt light bulb. However, to do their job, the heating and cooling system must be running.

In this regard, Trane Home Comfort Institute experts report that new technology in the field of electronic fan motors and controls is drastically reducing the cost of running a fan continuously.

And they say this new generation of motors and controls not only allows more economical air cleaner operation but also lowers overall operating costs, reduces noise and provides greater levels of comfort.