TODAY'S TECHNOLOGY AND YOU

Check Your Ducts for Leaks, Mold and Dust

Q: Dear Jim: I see ads for furnace duct cleaning. Our children have allergies. How can I determine if the ducts need to be cleaned and how can I compare various duct cleaning companies? What other maintenance should I do to my ducts? - Ann T.

A: Dear Ann: Some families can benefit tremendously from having ducts cleaned, and other families will notice no significant difference. Only your physician can determine what is causing your children's problems, so check there first. If poor indoor air quality, molds, etc. are suspected, then having the ducts professionally inspected and cleaned may help.

Your duct system may be driving up your utility bills and making your house uncomfortable even if it is perfectly clean. Many studies have shown the ducts in the typical home are leaky. When you look at a sheet metal duct system, there are many unsealed joints where one duct slips into another.

The key to an efficient heating and cooling (HVAC) system is getting the heated and cooled air to rooms where you need it. If a percentage of the conditioned air is lost in the basement, attic, utility room or inside the walls, you will have uneven temperatures in your home. This often causes you to set the thermostat higher during winter or lower during summer to stay comfortable.

When your furnace, air conditioner or heat pump is running, hold your hand near each duct-work joint to feel for leaky spots. Some spots will he visually obvious. Wrapping duct tape is a temporary fix, but it won't hold up for years. Aluminum tape is more durable and long lasting. Professional contractors use a thick gray sealer compound (Miracle Duct Sealer), which you can spread over the joints for a permanent seal.

Duct cleaning can also improve the efficiency of your furnace and air conditioner. Complete "duct cleaning" is more than just removing dust from inside the ducts. It also requires cleaning the blower, heat exchangers, cooling coils, and condensate pan. With these elements clean, air flows with less resistance through the entire system and the heat transfer from coils and heat exchangers surfaces is more efficient.

All ducts are going to accumulate some dust over time. This generally is not a problem that requires cleaning unless your family experiences health problems. A duct cleaning company can inspect the furnace ducts to show you how dirty they are. This is often done with a video camera in the ducts.

If mold is present anywhere in the entire duct system, you should have them cleaned. It is sometimes difficult to determine if ducts contain just dust or also mold. To be certain, a lab can check it for you. This sometimes is as simple as touching a piece of tape on an inside duct surface and sending it to the lab to be analyzed. Check with your local Environmental Protection Agency (EPA) or health department office for locations of labs.

There are several methods to clean ducts. One method is using an extremely powerful vacuum outdoors in a truck. A long hose is run to the furnace area and attached to the ducts. From the rooms, the dust inside the ducts is knocked loose with mechanical brushes, air jet brushes or air snakes. This eliminates any possibility of the dust leaking from the equipment into your house.

Another excellent method uses a smaller vacuum unit that is

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wheeled into your house near the furnace instead of being in a truck outdoors. Check with the contractor to make sure it has a high efficiency particulate airborne (HEPA) exhaust filter so the dust from the ducts does not get into the room air. A third method uses a rotating brush attached to the end of a vacuum nozzle. The brush/nozzle, along with a video camera, is run through each of the ducts.

There are actual differences in the quality of the work performed. A poor duct cleaning job can actually be worse than none at all because it stirs up the dust in the ducts. Look for companies in which their cleaning technicians have National Air Duct Cleaners Association certification.

Before you sign the contract, ask for visual evidence the ducts need to be cleaned. Ask the contractor how he plans to clean the other key components (heat exchangers, coils, pans, etc.). If one component is left unclean, it may re-contaminate the entire system. Ask for a full duct-length visual inspection after the job is done, preferably with a camera in the ducts.

Write for (instantly download - www.dulley.com) Utility Bills Update No. 733 - list of 550 certified duct cleaning companies across the country, descriptions of various cleaning methods and a checklist for selecting a duct cleaning company. Please include $3 and a business-size SASE. James Dulley, Illinois Country Living, 6906 Royalgreen Dr., Cincinnati, OH 45244

James Dulley is a mechanical engineer who writes on a wide variety of energy and utility topics. His column appears in a large number of daily newspapers.

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