B.S., Quincy

A. Nope, they're still around, and are a good but slow way of adding a bit of humidity to the house. They are not as fast as the powered humidifiers, but don't have the problems that the power ones have. The Handyman has seen them at NHD stores. Or, try the Miles Kimball catalog at (414) 231-4886. Plastic and metal tanks are also made by Street Level Supply, 4728 Bryant Ave. South, Minneapolis, MN 55409-2357; call (612) 824-7655.

Q. What do you think of using dehumidifiers in summer vs. central air to control the humidity in the house? I am concerned about the humidity in my house, which reaches 70 percent sometimes. I have put in a ridge vent to try to control some of the humidity.

JOY VERADT, Arlington

A. Dehumidifiers certainly will dry out the air, but they must be used in still air; that is, with all the windows and doors closed, which could be a problem when it is 90 degrees indoors and out. They are also expensive to operate. An air conditioner (central or individual) also dehumidifies as it cools, and while expensive to run, would be the better way to go, at least in very humid weather, say in July and August. The rest of the months (May, June, and September, ventilation will control the humidity, and at a lower cost.

That 70 percent relative humidity reading you are getting may not be accurate; it takes an expensive hygrometer to measure the humidity accurately.

Incidentally, while a ridge vent is a good thing to keep the attic cool in summer and dry in the winter, it is doing little to dry out the house, especially if the attic floor has a vapor barrier and is insulated.