Do-It-Yourself: Insulating attic's ceilings and walls isn't always practical

By Gene Austin
Friday, October 22, 2010; 9:34 AM

Q. My heating and air-conditioning equipment is in my attic. I know I am losing heat because the attic is very warm even in cold, cloudy weather. There is some insulation on the floor, but would it help to insulate the ceiling and walls of the attic? If so, what type of insulation should be used?

A. Attic ceilings and walls are sometimes insulated, usually with spray foam and often when the attic is to be used for living space. It is expensive and, in your case, I don't think it is practical. Some of the heat in your attic is probably infiltrating from the living space below, probably because there are unsealed gaps in the floor and the insulation is inadequate.

For example, gaps often occur where pipes, ducts and wiring penetrate the attic floor to the living area. Small gaps can be sealed with caulk; for larger ones, use foam sealant such as Great Stuff.

Repairing the gaps and bringing insulation up to standard should be your first priority, since it can significantly reduce your heating and cooling bills. More heat is also probably escaping from ducts in the attic. The ducts should be sealed and insulated (this also applies to ducts in crawl spaces, basements and other unconditioned spaces). Joints between sections of duct should be sealed with a metallic tape made for that purpose. Don't use ordinary duct tape - it won't last.

You don't say what type of insulation is on the attic floor, but, after any gaps in the floor are sealed and the duct joints are sealed and taped, you should be able to have cellulose insulation blown in to the R value recommended for your area (go to www.energystar.gov and enter "Recommended Insulation Levels" in the search field). If ducts run between joists or close to the floor, the cellulose will help insulate them; otherwise, wrap them with special duct insulation, sold at some home centers and building-supply outlets.

Q. I am thinking of having energy-efficient, double-pane replacement windows installed throughout my house, replacing old windows with single panes of glass. A contractor who wants to install the windows said I can recover the investment in time through energy savings. What do you think? Are replacement windows a good investment?

A. I am a big fan of replacement windows. You should definitely have some energy savings, but it is impossible to estimate how much because so many factors are involved, including the size of the house and windows, how you regulate your heating and cooling equipment, and the quality of the windows and installation. It could take a very long time to recoup your investment.

Contractor installation of replacement windows in a typical house can cost well over $10,000. If you saved $250 a year in heating and cooling costs, it would take 40 years or more to regain the investment. And don't count on recovering the full investment if you sell the house. According to a recent survey by Remodeling magazine (remodeling.hw.net), the average resale value is about 76.6 percent for vinyl replacement windows costing about $10,700.

But replacement windows have other advantages besides energy saving. They look good, reduce maintenance, increase comfort and help muffle outside noises. Plus, windows with tilt-in sashes are much easier to clean than old-style windows.

If you are a do-it-yourselfer with some skill, you can save a lot of money by installing the windows yourself. Most of the work can be done from inside the house. You can buy good-quality vinyl replacement windows at Home Depot, often for $250 or less for each window. Many windows come with installation instructions and some have lifetime warranties against leaking seals, which lets moisture enter between the panes of glass and causes clouding.

Q. My sump pump is 20 years old. I test it regularly and take good care of it. Should I replace it or do these things just keep going?

A. The typical life span of a sump pump is estimated at five to 15 years, which is more confusing than illuminating. Good quality and regular maintenance can take it to the high end, or longer. But if you have a serious recurring basement water problem, I'd say you are taking a big chance, both by keeping an old pump and apparently not having a water-powered or battery backup pump. If you install a backup that can take over in case of mechanical failure of the old pump, you can probably keep it for a few more years.

Questions and comments should be e-mailed to Gene Austin at gaus17@aol.com. Send regular mail for Gene Austin to 1730 Blue Bell Pike, Blue Bell, Pa. 19422.


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