Handyman on Call

Use awning to keep air conditioner unit cool

By Peter Hotton
Globe Correspondent / July 31, 2011

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Q. I have a small air conditioner in a south-facing window, which is very hot when the sun comes around, and I know is losing a lot of its cooling ability. I can’t move the air conditioner, nor can I install an awning. Is there something I can put on the unit to keep the heat down?


A. Just why can’t you install an awning? I ask that because it will be the best protection against the sun and its heat. The only other thing to try is to glue 1-inch Styrofoam panels on the top, sides, and possibly bottom of the air conditioner. Put the Styrofoam only on bare metal, not over vents.

Mr. McKeen wrote back that the window is one of a part of three windows, and that the Handyman got him thinking to install an awning over the single window. It won’t look great, he said, but it will stop the heat and I can take it down in the fall.

Q. I cleaned the mold off my bathroom wall with bleach and water, and it looks OK. But I discovered a big blotch of mold under some wallpaper, which I was able to pull off easily, and can eventually put back. How can I treat that?


A. Somehow, mold spores were in the paste, or were on the wall but could not grow until they became wet from the paste. It also may have been the old wheat paste, which mold spores will devour, as opposed to vinyl paste. The cure is the same for any mold: one part household bleach and three parts water. First, wash as much of the mold and paste as you can off the wall and the back of the paper, then treat the affected areas with the bleach solution. Let dry and put the paper back up with a vinyl paste or one that says antimold or mold resistant. Many naysayers are promoting certain products to fight mold, Moldex and Shoo Mold for two, saying bleach is toxic and will not last as long as their products. Yes, bleach is caustic, but it works.

Flickering CFLs Remember when J.J. Malone asked why his compact fluorescent, or CFL, light bulbs were flashing and flickering in an upstairs hallway ceiling fixture?

The Handyman thought it was a matter of heat, but asked for any ideas. Here are some of those ideas, by e-mail:

From Peg Preble of Jamaica Plain: I work as a residential electrician and I get a lot of work from CFL bulbs. The problem might be the base of the bulb is too big and won’t allow the bulb to screw far enough into the socket. Try a known, good incandescent bulb to see if the problem goes away. Also many of the CFL’s say in the small print “not for use in enclosed fixtures’’ where the electronics overheat.

From Don: It sounds like a contact-connection problem. Check the base of the bulb. I put a CFL in my garage door opener and came home one day to see it flickering/flashing. I just fiddled with the bulb and found a happy spot. I suspect that the base center contact is pushed down too far or has some corrosion, not allowing enough contact to get full power.

From Bill Card: The lamp had been designed by a company in Hingham, and I am an engineer, so I called their engineers. JJ probably has an illuminated switch. The lamp in the switch interacts with the ballast in the CFB to produce the flicker. I had an illuminated three-way switch, and when I replaced it with a conventional three-way switch the problem was solved.

From Duke: We had some compact fluorescent bulbs that would do some flickering even when the three-way switches were off. I think it had to do with the wall switches being the kind that are lit when the light is off. We experimented by trying different brands of CFL bulbs and found some that did not have the problem.

Q. The concrete slab and steps at my front entry are sinking and pulling away from the house, up to 1 1/2 inches. They are 33 years old. I asked a concrete man what to do, and he said he would put in a new unit using Sonatubes set 5 feet in the ground. Is that reasonable? What are Sonatubes?

M.T., Norwood

A. The man offers just the ticket for fixing the problem, creating a foundation so the new unit will not suffer heaving and moving in cold weather. Your original unit was simply set on the ground, where freezing earth expanded and pushed the unit all over the place. Sonatubes are big cylinders of heavy cardboard, set in place and filled with concrete. When the concrete sets, the unit is set on them. They go 5 feet into the ground, well below the frost line, so the new unit will not move an inch.

Q. My cloth shower curtain is an inner one, which fits inside the tub, and it has worked well but the bottom stays dirty no matter how I wash it. It says not to bleach it, so what can I do?


A. If nothing worked, resort to a mild bleach solution: one part bleach to five to 10 parts water. Or, use OxiClean. If that doesn’t work, live with it.

Call Peter Hotton is also in the g section on Thursdays. He is available 1-6 p.m. Tuesdays to answer questions. Call 617-929-2930. Hotton ( also chats online 2-3 p.m. Thursdays. To participate, go to