Check the Ducts in Your Home
Many people dream of finding hidden treasures in their new home. I even had some friends whose parents found silverware in a concealed barn safe that actually more than repaid the cost of their home purchase. Very few buyers are so lucky.
One place you are unlikely to find anything valuable is in the air ducts of a home. Combs, Cheerios, toy soldiers and far worse, but nothing of monetary value greater than pennies is the norm, along with lots of dust. Some of you may think that you know what’s in the dust of ducts, but the truth is usually far worse than can be imagined.
If you are considering buying a home with forced hot air heat or central air conditioning, air ducts are a certainty. They come in two shapes, round or rectangular. They may snake hidden through walls and floors: the supply ducts bring hot or cold air from the central unit to the individual rooms; the return ducts bring house air back to the central unit for heating or cooling. Ducts are usually only visible in the basement or attic. In older homes, the ducts are mostly metal; in newer homes the ducts are a mixture of metal and flexible, insulated plastic hose. As you may imagine, thorough duct cleaning is not an easy task. Somewhere between the return and the supply, usually just in front of the blower, is a filter that must be replaced regularly which is supposed to, but rarely does clean the air.
Make it a habit to check the listing sheet to see the type of heating system that exists in the homes at which you look. Ask the broker to show you an air register if you don’t know what one looks like. Look inside several, preferably with a flashlight. If you see a thick mat of debris, count on spending several hundred dollars to have the ducts professionally cleaned. Be sure to check at a return grille, because these draw in dusty house air and are usually the dirtiest.
The dust in ducts consists mostly of fibers (from rugs, clothing, etc.) and skin scales that we shed from our bodies at a rate of about 30 grams per month. If dogs and cats have ever lived in a house, you can be sure to find their dander mixed in with ours. But what we see as dust looks like food to the microscopic creatures that forage in the dusts of homes. Dust mites, book lice, silver fish, carpet beetles and predator spiders are some of the more common inhabitants.
The ecosystem only gets really ugly when moisture is introduced from leaks, high humidity or condensation, because this is when molds start to grow in the dust. Occasionally, I will find that the dust in a duct consists mostly of mold, the creatures that feed on it and their fecal droppings. The dust in such ducts can be very hazardous to an individual’s health, particularly someone with asthma or allergy, and disturbed duct dust has caused severe asthmatic reactions.
Blowers, filters and air conditioning coils can become equally contaminated in any type of ventilation system, so “duct cleaning” should really include all components of the system with which the circulated air comes in contact. This work must be done professionally; just using the wrong type of vacuum cleaner can contaminate a space for a sensitized individual. Only hire a contractor who will uses brushes along with vacuuming; vacuuming only in combination with compressed air to dislodge dust is inadequate. Avoid low cost, advertised specials. A thorough, professional cleaning takes several hours and you should not expect to pay much less than $300 for the job if done correctly. If you have questions, call NADCA, the National Air Duct Cleaners Association at 202-737-2926.