How to Insulate Your Home

Hey Mr. Green,

My attic has part rock-wool insulation and part fiberglass, to the depth of the ceiling joists. I'd like to throw a "blanket" over the existing layer, preferably one that won't release bits of fiberglass when I walk around up there. Is there a nontoxic, nonflammable, ideally encapsulated insulation that doesn't cost an arm and a leg?

--Anna in Grass Valley, California

You need at least another six inches of insulation up there, as do millions of others, according to the U.S. Department of Energy. That's because 40 percent of a typical home's energy use goes toward heating, and a lot of it is lost through the ceiling. (The DOE's Web site offers customized insulation recommendations.) Encapsulation insulation (in which the fiberglass fibers are sealed behind a protective film) is available.

Yes, fiberglass can irritate the body, but I think its dangers have been exaggerated. If you're concerned about formaldehyde, you can use formaldehyde-free fiberglass insulation, and all fiberglass is made with up to 40 percent recycled glass. Other options include insulation made of recycled paper.

Whatever you choose, avoid tromping on it: You'll squish out its R-value, and with the joists concealed by the new layer, one misstep could send you plunging through the ceiling (truly costing you an arm and a leg). Installing insulation can be tricky, however, especially in an older home, so I strongly recommend consulting a reliable installer before you begin.

Finally, don't forget to insulate and weather-strip the door that leads to the attic, and remember that if your house has leaks around windows, doors, pipes, vents, ceiling lights, or even electrical outlets, you can lose 30 percent of your heat. The DOE provides excellent information about finding and dealing with these mini-escapes here.

How to Throw an Ecofriendly Kegger

Hey Mr. Green,

I'm in my senior year of college. I live off campus, and we throw a lot of parties. What appalls me is the amount of nonrecyclable plastic cups we go through. If we use 100 cups per party and have 12 parties a year, that's 1,200 cups we're wasting. Are there any reusable plastic cups that are cheap and environmentally friendly?

--Dan in Titusville, New Jersey

The mere thought of heaps of disposable cups, replete with congealing backwash and reconnoitering insects, can spur even the most environmentally indifferent into action. I recommend rigid plastic tumblers, in part because they provide a nice example of how helping the environment can also save you money.

I could have taken the easy path and recommended biodegradable cups made from corn, potatoes, or other "renewable" substances, but I haven't found convincing evidence that biodegradables are significantly better for the environment than regular plastic. And glassware is neither a safe nor a cheap solution.

Rigid plastic tumblers are sufficiently durable for long-term reuse. Since no self-respecting college party host would countenance vessels smaller than 16 ounces, I assume that's your current choice. You can get nondisposable plastic tumblers at restaurant-supply stores or online for $1.50 or less each--$150 for the 100 you need. Of course, you have to factor in additional funds to cover theft, stomping, and inadvertent melting--not to mention the time and water needed to wash them.

But if you're spending $240 annually for the throwaways, even if you use the sturdier cups for only one year, they're a better investment--for your pocketbook and the planet.