Home and commercial building owners who have heat tape installed on roofs or in gutters to help prevent winter ice dams often find that heat tape also warms up their electricity bills.
Typical heat tape burns electricity at six to nine watts per foot per hour.
That means each 100 feet of heat tape operating 24/7 can translate to an added monthly cost of $40 to $60 to operate heat tape, says Eileen Wysocki, energy auditor for Holy Cross Energy. Some larger houses and businesses in the region are running hundreds of feet of heat tape.
Using a heat tape timer can help make the system run more efficiently when it's needed, and turns it off automatically when it's not needed.
Customers of Holy Cross and Glenwood Springs Electric can claim rebates on the installation of heat tape timers. Find contact information for local electricians to do the install here.
Using heat tape for maximum effectiveness and minimum energy
It may seem counterintuitive, but the best time to run heat tape is during the day. Holy Cross Energy’s residential audit program recommends using a timer to run heat tape from 6 a.m. to 6 p.m. whenever snow or ice is sitting on the roof.
When the sun is out and snow starts melting, the dripping water needs a path to drain off the roof. Heat tape can melt a channel in the underside of the snowpack on your roof and give water a route to drain out. And heat tape installed in gutters and downspouts allows water to drain away from the roof, rather than getting plugged up by a dam of ice.
Electrician Nathan Helfenbein of Basalt said heat tape is not effective enough to sufficiently melt ice during cold evenings, and it will just waste power all night long.
Energy coaches say the goal is to run heat tape only enough to keep a channel cut in the snow or ice.
Effective heat tape options include a timer that powers the tape for about six hours a day, from late morning to late afternoon, or setting the controls to use a temperature set point.
Control times and temperatures will vary from one building to another based on elevation, how the roof catches the sun, and how well the building is insulated.
Watch out for ice dams
The experts advise homeowners and building managers to keep an eye on their roofs all winter for ice damming. If blocks of ice build up under the snow, that could indicate inadequate insulation, noted Robert Roper, an energy auditor and longtime electrician in El Jebel.
“As a certified auditor, we look at those ice dams and icicles hanging from the roofline as a possible indication of not enough insulation in the attic,” Roper said. “If you do the air sealing and insulation work to begin with, the need for heat tape on the roof is vastly reduced.”
Effective heat tape installation and operation
Helfenbein recommends that homes and buildings needing heat tape go with a hard-wired system that uses the more efficient voltage of 220. He said those systems should be connected to a GFI (ground fault interrupt) breaker and be self-regulating so that they burn hot where the tape is touching ice.
Once the roof is melted out, heat tape should be switched off. Every summer, Wysocki said she finds homeowners who are paying high electric bills because they forgot to turn off the heat tape. She recommends marking the calendar for mid-April or making a note to turn off heat tape at the breaker switch after the last big spring snow.
Conscientious homeowners can also install a heat tape system with a manual toggle switch so they can easily turn on the tape only when it’s needed, and switch it off later.
Some facility managers of commercial buildings report tying the heat tape system into the building’s automation controls. Nick Kertz, chief engineer at the Snowmass Club, said he sets controls so the heat tape only operates when the air temperature is above 32 degrees and the sun is out.