Q. I’ve been wondering if the air ducts in my house need cleaning. I have lived here for 35 years and they have not been cleaned in that time. It is expensive and I would like to know if problems could arise. Also, how often should air ducts be cleaned?
A. After 35 years, it would appear to be obvious that duct cleaning is needed. But that is not necessarily the case.
No less an authority than the Environmental Protection Agency recommends that air ducts need to be cleaned only if they contain substantial deposits of mold or dust, are infested with vermin, if family members have allergies or other respiratory ailments, or if there is a musty odor coming from the ducts.
The EPA suggests consulting with the service that you use to maintain your heating-cooling equipment.
Firms that clean air ducts can also be consulted; some provide free inspections of the ducts. But keep in mind that duct-cleaning companies want to sell their service and their opinions might be prejudiced.
It is sometimes possible to check inside ducts yourself by removing a register and using a flashlight and mirror to examine the inside of the duct.
Air-duct cleaning can cause problems, especially if cleaning is done by poorly trained workers or the equipment used is defective.
Contaminants can be released into the air by faulty vacuum systems and clumsy work can even damage the heating-cooling system.
For more information on possible problems and answers to many other questions about air duct cleaning, visit the EPA Web site ( www.epa.gov) and search for Air Duct Cleaning.
Another source of information worth checking is the Internet site of the National Air Duct Cleaners Assn ( www.nadca.com). Again, keep in mind that this is a trade organization interested in selling the services of its members.
Q. I have a large wood table with a very dark stained finish. There are some very fine scratches in the finish, which appear to be only in the surface finish. Is there an easy way to repair this?
A. The easiest solution I know about is to use a liquid scratch cover, which is simply a stain that will seep into the scratches and make them less visible.
Old English is a scratch-cover brand that has been around for many years and works well; be sure and get the version intended for dark finishes.
A pigmented oil stain, available in many colors at home centers and paint stores, can be substituted for liquid scratch cover; just wipe a little over the scratches, then wipe off the excess and buff with a soft cloth.
Another treatment is to use a tinted paste wax. Waxes in various wood shades are available from Woodcraft ( www.woodcraft.com). Type Tinted Paste Wax in the Woodcraft search space for prices and a list of the available tints.
Q. Our older house gets a musty odor in warm weather. The odor comes from the unfinished attic. Can you suggest a solution?
A. Musty odors are usually caused by moisture, which in attics is often the result of poor ventilation. The attics in many older houses are poorly ventilated, allowing moisture that rises from the living area to accumulate and sometimes foster mold growth.
For long-term relief, improving the attic ventilation could be the best solution. A good venting system includes vents in the soffits or roof overhangs and sometimes a vent at the ridge of the roof. This allows fresh air to enter and escape, taking attic moisture with it.
Powered roof vents (fans) are seldom necessary. In some cases, unpowered turbine vents can be installed in the roof to increase air flow and release of moisture and hot air. You should also check the attic floor to make sure it is adequately insulated and a vapor barrier.
If you are looking for a quick fix, some readers say they had good results clearing up musty odors with moisture-absorbent chemicals sold at home centers and on the Internet under such brand names as Damp Rid and Moisture Sorb.