Q: I plan to add insulation to my attic floor. Which would you recommend: placing six-inch batts over the floor, or pouring loose-fill insulation (which comes in bags) over the area?

A: Both methods will work with equal efficiency if you pour enough of the loose-fill to give you the same R-rating as the as the six-inch batts. All insulation now has an R-rating on the package. In the case of bags of loose-fill, they tell you what the R-rating will be for the various depths or thicknesses, so just be sure you pour enough to match the rating you want.

Q: One of our bathrooms, which has a shower stall and no tub, has a moisure problem. We washed off mildew that was growing on the outside wall of the bathroom, near the ceiling over the shower stall. We installed a ceiling fan that vents into the attic, but this seems to have added to the problem because the mildew is now spreading all over the ceiling. Do you have any ideas about how we can solve this problem?

A: Added ventillation is definitely what is required, but you made a mistake when you had the exhaust fan vent into the attic. This only sends the moisure up there, where it apparently settles onto the attic floor, which is the upper side of your bathroom ceiling.

That is why a vent fam should never empty into an attic; it should exhaust directly outside. This can be done by installing the fan in an outside wall or by using ducts to connect it to the outside. The fan should be used whenever the shower is in use, and it should be left running for some minutes afterward. Also, when the mildew is washed off, use a solution that kills the fungus: one part liquid laundry bleach mixed with three parts water will do the trick. Scrub on, let dry for about 15 minutes, then rinse off. Then repaint with a mildew-resistant paint.

Q: I have two houses heated with hot air, and both have built-in humidifiers. In one, the humidifier is attached to the cold water line, while in the other the unit is attached to the hot water line. Which is correct?

A: It really doesn't make too much difference as far as operation of the humidifier is concerned; both will work. However, hot water is really unnecessary, so it seems to me that using hot water is wasting energy and adding needlessly to your fuel bill.