There is a new type of shallow water heating solar collector that is designed to look like a skylight on your roof. It lies flush against your roof surface and is less than 2 1/2 inches deep.

Instead of using the standard copper tubes for the solar absorber plate, this system uses a black EPDM rubber absorber. This is energy efficient and does not have to be drained for freeze protection. The EPDM material can handle the expansion and contraction of the winter daytime thawing and nighttime freezing cycles in the winter.

Inside the very shallow collector, the EPDM absorber plate lies on closed cell foam insulation to minimize heat loss. Instead of using a glass cover, double insulated and ribbed clear polycarbonate plastic (bulletproof glass) is used. It is virtually unbreakable.

Using the plastic cover also offers automatic overheating protection. When the solar collector gets too hot, if the water flow stops, the plastic cover bows slightly from the heat. This opens small vent holes around the edge. When it cools down again, it straightens and they close.

Although your roof may not provide the optimum collector angle for highest efficiency, the lower cost of this type of collector makes it feasible. This also makes it an easy do-it-yourself job since mounting brackets and supports are not needed.

Another new type of solar collector system uses concentrating collectors. Although these are usually tilted up from the roof, they are smaller than standard flat plate collectors. They have a special sun-tracking sensor so they rotate to follow the sun throughout the day. The high concentrating temperatures can provide free and very pure distilled drinking water too.

If you have a sunny spot, you can install solar collectors at ground level. For heating water throughout the year, they should be tilted up from horizontal at an angle equal to your area's latitude angle.

You can write to me for UTILITY BILLS UPDATE No. 227 showing a list of manufacturers of all types of water heating solar systems and detailed information on the two new solar systems discussed above. Write to James Dulley, The Deseret News, 6906 Royal Green Drive, Cincinnati, OH 45244. Please include $1 and a self-addressed STAMPED BUSINESS-SIZE envelope.

Q - I have thermal double pane windows in my house and several of them have gotten foggy. Is there any method to repair them myself. If I have to buy new panes, what type should I get? H.L.

A - It is difficult and hazardous to try to separate the glass panes yourself and to try to reseal them. There is also a moisture absorbing desiccant powder inside the windows to stop fogging. This must be dried out first.

You will probably have to replace the foggy glass pane. To ensure the proper fit, buy the glass from the original window manufacturer. Low-E, argon gas-filled glass will be the most efficient panes to fit the sash.