Snow Removal and Radiant Heating

It always seems that the rigors of winter move most forcefully against us when we’re dealing with that third or fourth snowfall. Backs throb and tempers strain to accommodate Mother Nature’s tantrum.

There is, however, one way to rein in the nuisance of dealing with snow and ice: by melting it away! Snow shovels, plows, blowers, salts and other chemicals … not required. By introducing your clients to this technology, you can help them have a stress-free, accident-free winter.

A snowmelting system works with electric heat, or by circulating warm fluids through tubing inside a surface, so that walkways, driveways, and other areas remain dry and clear. Since most snowmelting systems are “hydronic” (using circulated fluids to heat these outdoor masses), that’s what this article will focus on.

These systems are ideal for residential uses and for commercial applications — especially critical areas like hospital and senior-housing entry areas, helicopter pads and delivery ramps. A snowmelting system performs a valuable, perhaps life-saving, function.

It’s also the perfect complement to an artfully stained, stamped or otherwise decorative concrete surface. Why shouldn’t your craftsmanship be admired year-round?

Here are some of the benefits that you can share with potential customers. Icy surfaces are no longer a threat. Home or facility maintenance costs are reduced because snowplowing is eliminated or reduced, and ice-melting chemicals aren’t required. These chemicals kill landscaping, require cleaning when tracked inside, and seriously degrade concrete and asphalt.

And, consider this: The cost of the system is more than returned with one avoided “I slipped and fell on your sidewalk” lawsuit. Even insurers recognize the value of these systems, rewarding commercial building owners with reduced insurance rates.

Typically, most of the components of a snow melting system, especially the heating plant, sensors and controls, are installed by a plumbing and mechanical contractor. But concrete contractors should be involved when it’s time to embed the heating elements in the slab.

Snowmelting classifications
Snowmelting systems are generally grouped into three classifications based on the amount of snow actually melted at design conditions:

• Systems designed not to melt snow while it’s falling, but afterwards.
• Half the snow is melted during snowfall, the rest afterwards.
• All snow and ice is melted while falling.

Snowmelting Loads
It takes a lot of energy to melt snow: about five to six times the load required to heat a building of similar size. For example, it may take only 30-40 Btu/hr per square foot to heat the inside of a structure with a floor-warming (radiant heat) system. But it can take up to 150 Btu/hr-square foot or more to melt snow and ice and ice from a surface. When a snowmelt is first started, much energy is lost when it’s moved from the heated pipe to the surrounding ground, which is frequently frozen hard. Because the warmed fluid gives off heat as it travels through the slab, installers prefer to lay the tubes in a spiral or serpentine pattern to distribute the heat evenly.

The Importance of Insulation
Insulation substantially reduces operating cost. When added under the slab and at its perimeter, heat loss into the ground is reduced, and the slab heats more quickly. The preferred material is usually 1- or 2-inch thick rigid polystyrene foam.

Insulation also helps channel the heat in the direction it’s wanted. Contrary to popular belief, energy doesn’t necessarily rise. It travels — in any direction — from hot to cold, from areas of high concentration to low concentration. This works great for interior spaces. But outdoors, four “thieves” work in tandem to steal the heat.

Thief #1: Ground. Heat is literally sucked into the surrounding ground. Heat loss to the ground is about 10-15 Btu/hr-square foot.

Thief #2: Atmosphere. The atmosphere works even harder than the ground to swipe the heat you’ll be putting into the slab. That’s why energy must be fed into the slab continuously. Loss to the atmosphere can be up to 90 Btu/hr-square foot. That’s a lotta’ heat.

Thief #3: Water. As the snow or ice turns into water, it runs off into drains, storm sewers and into grass. This water runoff carries precious energy away from our slab, too. Care must be taken to ensure the water runoff from the snowmelt system has a place to go. If not adequately designed for, water will run off the slab and “pool” in low spots around the system and freeze. It may be necessary to heat drain pipes and water runoff areas.

Thief #4: Evaporation. As melting snow and ice turn from liquid to gas, more energy is carried off. This energy must also be replaced by our heat source.