March 23, 2009

Greg wants to save money on his gas bill: What do you think of those shiny foil layers that go into the attic? Do they really save heat?
My research has shown that they aren’t very effective in climates that mostly heat, like ours—especially considering their relatively high cost. The foil lies on top of the attic insulation; trouble is, it accumulates a layer of wind blown dust, so the reflective characteristics disappear over time. Some folks have outsmarted themselves by installing it on the rafters, just under the roof shingles. But that creates an intense heat pocket that prematurely deteriorates the roof.
In climates that cool more than half the year, there is some evidence that the foil will marginally lower cooling costs. But that requires removing that pesky dust layer to keep the surface shiny.

Robert has more radon questions: You wrote last week about radon as it might come up in a home sale. Is there a coating I could apply to the basement walls to keep it out?
Probably not. Generally, radon comes up through cracks and holes in the basement floor (or through crawl space dirt). It’s a fairly heavy gas so it accumulates in the lower parts of the house. Mitigating the radon level to get it below the EPA recommended level of 4.0, is usually a two-step process. First, a high quality sealant is applied to all cracks and holes in the floor: at pipe penetrations, and even around the perimeter at the bottom of the foundation. Then a fan and duct system is installed to create a negative pressure under the floor, whereby the radon is sucked up and exhausted outdoors, before it can get inside the basement airspace. It’s not as complicated as it sounds, because most homes have a perimeter water drain system. The fan is simply connected to one of those pipes in a window well.
You can see that this is more than just another DIY project and is best left to mitigation companies who will guarantee “no more radon”. If your radon level is just barely above the maximum, you might be able to get it down by applying sealant only. Give it a try and be sure to retest afterwords to check the efficacy of your work.

Tom has an elderly water heater: It’s in the crawl space and it’s one of those short tanks. It’s natural gas, but a friend said I might not be able to replace it. Is that true?
Unfortunately, the so-called “stubby” water heaters are now only made in electric versions. Apparently, they just weren’t selling enough to continue their manufacture. They were quiet expensive compared to their more upright cousins—and that may also have been a contributing factor. They do, however, make electric versions of these little guys. What that means to you is that you’ll have to pull a 240 volt circuit wire to the current water heater location. If your present gas model is getting on in years, you might want to get the electrical work done now, so that, in the event of a failure, you’ll need less time to get a new one in and hooked up.
Of course, it will cost more to heat water electrically, but you can mitigate some of that extra expense by installing an insulating blanket around the tank. In fact, that would be a good idea right now with your existing tank, since crawl spaces are a little cooler than the rest of the house, and, hence, suck more heat through the tank walls.