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Most snow storms in each area have very similar characteristics. In most areas the temperatures start above freezing, and it starts snowing at about +34° F. and stops at about +20°. If you are designing a heating system for a house with a design temperature of 0° F. you can add 1000 sq. ft. of snow melt without increasing the size of the heating system, if you use a snow control that turns the snow melt off below 18° F.
12" centers work well in both concrete and asphalt.
All loops need to be the same length to make the system work evenly.
Although we have used 1/2" tubing on many systems, we have found that using 5/8" tubing can prevent some start-up problems.
Although many snow melt systems are designed with polyethylene tubing we recommend only PEX tubing.
Snow melt systems need 50 to 100 Btu's per sq. ft. to operate properly.
Polypropylene anti-freeze is thicker at low temperatures than polyethylene anti-freeze and can cause problems on low temperature start-ups.
A low temperature start up, is when the temperature has been below 0° for several days and comes rapidly up to the twenties and starts snowing. In these areas you should use polyethylene anti-freeze and use minimum mixtures.
Copper boilers are available that can be placed in the shrubbery next to the driveway, and with a automatic snow control, work well in medium sized systems.
For asphalt systems, light equipment can be driven over the tubing by running water through the tubing until all the air is removed, then closing off both ends and maintaining at least 60 pounds pressure.
Never use an on-off switch to control a snow melt system. Always use a simple wind-up timer or a automatic snow control. A snow melt control will turn the system on when it starts snowing and off when it stops, and cost less than 200.00$. See http://www.networketi.com
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