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handyman on call

A second thermostat may help trim heat bill

Q. My father lives in a small cape built in the ’50s. It has forced hot water heat. The upstairs is generally at least 10 degrees warmer than the downstairs where he spends all of his time, therefore wasting a lot of heat. We’ve tried bleeding the radiators and turning off the radiators. The thermostat is downstairs. The burner is fairly new (replaced five years ago).

 The burner guy doesn’t know what to do about this other than what we’ve done. Should we have a thermostat put in the upstairs? Perhaps we are not bleeding the radiators correctly — could you explain this? Or should we contact our service and have them try again?

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Martha Monohan

A. Bleeding the radiators might make them more efficient, but what confuses me is that turning off the radiators upstairs makes no difference. Call your burner man to see if the upstairs heat can be stopped. Adding a zone or an upstairs thermostat should work, too, and that should be done by the burner man.

Q. I live in a 13-year-old well constructed home but this winter I have begun to notice a problem with window moisture and its effects on the window frames. During the cold of winter, we run a humidifier. However, whenever the temperature has dropped much below zero we have developed a slight rim of condensation along the bottom of some windows. This has led to the deposit of a black substance along the woodwork. We do not have an air exchange system, though I do not understand how that would prevent any problem other than to reduce internal moisture that we are trying to replace with the humidifier.

 My questions: 1) What is this black substance? 2) Will this cause any long-term damage to the woodwork? 3) Is there a way of avoiding it other than turning off the humidifier or replacing with windows of higher insulation value? 4) Is there any treatment for woodwork that already has a black deposit? 5) What is a full house air exchange system other than a system that removes internal air and replaces it with a dryer colder external air that needs to be heated?

John Virant, St. Paul

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A. Turn off the humidifier, which is causing condensation and the black stuff, which is mold. Remove the mold with a solution of 1 part bleach and 3 parts water. I think people in very cold climes may not know what mold is or looks like, because the colder the area, the less likely mold will grow. Mold can be other colors as well. Use the humidifier sparingly, and shut it off if you see mold anywhere.

 As for the rest of the questions: Mold can ruin a painted surface over time. Keep the house dry(er) to prevent mold. Treat it with the bleach/water solution.

 Finally a full house air exchange is not what you think it is, because it exhausts humid air and brings in fresh outdoor air, but it also transfers the heat of the outgoing air to the incoming air, at little loss of heat. I suggest you invest in an air-to-air exchanger, which should have been installed anyway because your house is extremely tight and has a low exchange rate.

Q. My garage roof has half-dollar and quarter-size greenish yellow blobs on parts of the roof. What can I do to eliminate this problem?

Martin Finn

A.Those are lichen, a combo of algae and mold, and sometimes they are difficult to remove. Try soaking them with water and scraping with a wood spatula, being careful not to gouge the shingles. If that doesn’t work, soaking them with vinegar will kill it and make it easier to remove. If none of the above works, let it be. The lichen is harmless, only a bit unsightly. Sometimes you may see it on trees. It doesn’t hurt the trees.

Q. Recently a column addressed problems with stains on marble and granite counters. Are Quartz and Silestone also vulnerable? Do they need sealing?

Rosemary Noren

A. Quartz and Silestone are made of Corian or a similar plastic, and do not stain much at all, nor do they need sealing. If one gets a stain, it can be sanded off.

Q. I have matte black tiles that have been marred by a valve leak. I have high mineral content water. It appears as though the leaked water has discolored the tiles leaving white rings. Any suggestions?

Gabe Buglione

A. Those are water marks, and they can be removed by rubbing with Mr. Clean Magic Eraser, providing just enough abrasion to do the trick.

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 or e-mail photton@globe.com. He also chats online from 2-3 p.m. Thursdays on www.Boston.com

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