JAMES DULLEY Cutting your utility bills Solar water heater saves money, sets an example

Q. With energy shortages, global warming and rolling blackouts, I need to do my part and save a few bucks too. I want to make a simple low-cost solar water heater. What is the simplest design to build?
A. Heating water with the sun is an efficient and effective use of solar energy for all climates. Unlike solar space heating that is used only in the winter, solar water heating is used and saves money year-round.
Water heating typically accounts for about 20% of a family's annual utility bills, and a simple solar water heater can contribute up to half of your hot water needs. In addition to saving money and protecting the environment, building a solar water heater sets an excellent example for your children.
There are several designs of effective solar water heaters that an average do-it-yourselfer can easily build using many scrap materials.
Among these designs, a batch-type design is the simplest. All the materials required to build one should be less than $100 to yield a payback within a year or so.
If you are a do-it-yourself-challenged person, don't give up.
Ready-to-build solar batch kits, with two 30-gallon tanks, double-wall glazing, foam insulation, etc. and with an instruction booklet are available. You can also buy completely assembled batch units that are easy to hook up yourself.
A solar batch water heater is used as a preheater for your existing water heater and is usually mounted on the ground on the southern side of your house. There are no ugly rooftop collectors and very little maintenance.
The plumbing is very simple. The cold water pipe leading to your water heater is connected to the solar batch unit inlet. Its outlet is connected back to your water heater. Install two low-cost valves at the cold water inlet to your water heater so you can bypass the solar heater anytime you wish.
One or two water tanks in the batch heater are exposed to the sun. This preheats the incoming water. On a sunny day, the outlet water will be warm enough that your existing water heater will not have to come on at all.
A simple bread box design is basically a black water tank, typically 30 to 40 gallons, in a plywood box with a clear top. A discarded water heater tank, stripped down and painted black, works great. An old storm window/door or clear acrylic plastic is effective for the clear top cover.
Insulating the sides and back of the box is important to minimize the loss of solar heat. If you are handy with tools, build a hinged insulated cover with reflective foil to direct more of the sun's rays on the tank. Close the insulated covers at night or just throw an old quilt over the clear top.
Q. I was watching a TV news program about excessive mold growing in a house. They recommended setting the humidistat at 50% to stop it. Shouldn't the setting be changed with the weather?
A. The program was technically correct, but misleading. You will not have a severe problem with mold with a relative humidity under 50%.
Unfortunately, setting your humidistat at 50% will not help.
Relative humidity is dependent on the indoor air temperature. If the humidistat on an inside wall says 50%, the air near a cold outside wall or window will be higher. This may result in mold problems. Reduce the humidity level as it gets colder outdoors.
XWrite for Update Bulletin No. 832 which gives do-it-yourself instructions, diagrams, materials list, plumbing schematic for several designs of batch solar water heaters and a list of ready-to-use batch solar kits. 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.