• Snowmelt 101

    Feb. 22, 2005
    There are many good reasons why your customers may be interested in hydronic snowmelting systems. First of all, snowmelt systems eliminate the need to

    There are many good reasons why your customers may be interested in hydronic snowmelting systems.

    First of all, snowmelt systems eliminate the need to have someone shovel and salt walkways and driveways.

    Secondly, they reduce the chances of a slip and an injury (and, possibly, a lawsuit) by an employee or customer.

    Finally, there’s aesthetics. Many of our bank and office building customers like snowmelt systems because of the clean, professional image it brings to the exteriors of their buildings. In addition, we recently installed a large snowmelt system for a local Harley-Davidson dealership. It can be tough to sell motorcycles in Michigan in January, and the snowmelt system helps create an illusion of nice, summer weather. Snow and slush underfoot doesn’t exactly put motorcycle shoppers in the buying mood!

    Rules of Thumb

    There are a few keys to designing and installing an efficient snowmelt system. You want to get the design and installation right the first time. If you don’t, and problems arise after the concrete has hardened, you’re looking at a significant additional expense.

    Here are some quick rules of thumb to consider when you design and install a snowmelt system. Keep in mind that these will vary depending upon your area of the country — in other words, they’ll vary depending upon how cold it gets, for how long, and whether you’ll generally be trying to control and remove light snow, heavy snow, or ice.

    Supply water. Your supply water doesn’t need to be very hot to keep a concrete slab warm enough to melt snow. Generally, supply water in the 80F to 140F range will handle any snow or ice melting task. Choose and size the boiler accordingly, and use the lowest temperature necessary for your area. This will save the customer money on fuel costs, and extend the life of the concrete by avoiding extreme temperature swings.

    Average BTUS. Once again we’ve got the numbers 80 to 140. In this case, they refer to the Btus per sq.ft. that you’ll want your system to deliver, based upon the harshness of the climate.

    Spacing of tubing. For milder climates with light snow, spacing of 10-in. on center should suffice. For colder climates with more snow, the spacing should be tighter, but no closer than 6-in. on center.

    Freeze protection. Your supply water will need to be mixed 30% to 50% with glycol anti-freeze.

    Insulation. This is an important step. You must insulate the bottom and edges of the concrete slab. If you don’t, the heat from the slab will simply go into the ground, and your system will be a massive flop.

    We generally use “blue board” insulation or bubble wrap. Either works well, although if you’re using bubble wrap you’ll have to place a wire mesh underneath to provide a sturdy base to fasten the tubing.

    Don’t forget the edges. Most installers can figure out they need insulation under the tubing, but then overlook the vertical edges of the slab. Uninsulated slab edges will kill the efficiency and effectiveness of your system.

    Check for leaks. Before the concrete is poured, pressurize the system to 60 psi with either water or air. Maintain the pressure for 24 hours prior to the pour, and keep it pressurized during the pour. No leak is a good leak, and it’s much better to discover and correct any leaks before the concrete is poured or has hardened.

    Controls. You have two basic choices when it comes to controlling a snowmelt system: slab sensors, and outside air/humidity sensors. Slab sensors detect the accumulation of snow or ice, and send a signal to the boiler and pumps to deliver hot water to the loops in the slab. Outside air/humidity sensors determine if the conditions are right for snowfall or ice accumulation, and kick the boiler and pumps on in anticipation.

    An Attractive Niche

    Snowmelt systems are growing in popularity in our corner of Michigan, and our experience with them has created an attractive business niche for us.

    What I’ve presented here are some simple elements of creating an effective snowmelt system. There are several good system design software packages and control packages on the market. Check with your local hydronic equipment supply house for more information before you tackle a snowmelt project.

    Dean Anderson is sales and design manager for Seaman’s Heating/Air Conditioning/Refrigeration, Grand Rapids, MI. He can be reached at 616/458-1544 or [email protected].