Sunday, August 19, 2001
Q. I have a few attic vents, but I can still feel the sun's heat radiating from the ceiling during the afternoon. It is uncomfortably warm. What do you think of installing more standard vents or new solar vents?
A. People are often surprised how much discomfort and high utility bills are due to heat blasting down from a hot roof. Attic floor insulation is relatively ineffective at blocking radiant heat from a 150-degree roof. Installing a solar attic vent fan helped cool my own second-floor bedrooms.
The best method to block this heat is a combination of adequate attic ventilation and low-emissivity, reflective foil stapled under the roof rafters. The ventilation helps reduce the roof temperature caused by the intense sun and the foil shields your ceiling from the radiant heat transfer.
Solar-powered attic vent fans are an ideal fit for keeping your attic cooler in the summer, and they operate for free from the sun's energy. A small solar cell panel converts the sun's energy into electricity. As the sun's rays get hotter in the afternoon, the vent fan automatically runs faster.
Causing damage: Attic ventilation is also needed in the winter to remove moist air that leaks up from the living areas. If the attic is not well vented, this moisture in the air can condense and drip down on the insulation. Wet insulation is not only ineffective, it can also damage the attic lumber.
Solar-powered vent fans range in size from mini-four-inch-diameter models to the more typical 12- to 16-inch sizes. The mini-model has a built-in rechargeable battery so it continues to run when the sun goes down.
The two basic designs of solar fans are self-contained [integral] and remote. The self-contained models have the solar cell panel built into the top of the fan housing. These models are excellent for a roof with a southern exposure.
For non-southern roof exposures, or shade problems, use a remote design with a separate solar cell panel and a fan. With up to a 20-ft. safe, low-voltage wire, you can locate the panel to directly face the sun for maximum electricity output. You can also install an on/off switch if you wish.
Since there is no electrical wiring, installing one or two solar fans is a simple do-it-yourself project. You remove a few shingles and saw a round hole through the roof. Nail the fan in place, and replace the shingles.
Natural attic ventilation is also an option, but you will have to install many more roof vents or a ridge vent along the entire length of the roof peak. Installing turbine vents instead can increase the amount of natural ventilation with fewer vents required. A unique electric-powered internal ridge vent is still another option.
Q. We are building a new house, but it is not extremely large. I am trying to find some way to build a combination shower and sauna unit.
Is there such a thing made, or can I make one myself?
A. That combination would not work very well. Saunas operate at very high temperatures; therefore, they must be made of wood so you don't get burned. This would not be consistent with a typical shower.
You might consider a steam generator instead for your shower. There are many small models available specifically for your application. Make sure to install airtight shower doors to avoid losing heat and moisture to the rest of the house.
XWrite for Update Bulletin No. 657, which gives a buyer's guide of 11 solar-powered attic vent and turbine fans listing air flow ratings, watts, sizes, features, prices and a sizing chart. Please send $3 and a business-size SASE to James Dulley, The Vindicator, 6906 Royalgreen Drive, Cincinnati, Ohio 45244. For an instant download, visit James Dulley online at www.dulley.com.