HEAT CABLE PREVENTS ICE DAMS & FROZEN GUTTERS
- dovetailrain
- Dec 16, 2025
- 3 min read
Updated: Jan 9
Here in Montana, winter often leads to ice dams on roofs and frozen rain gutters. Many people have dealt with leaks in their homes caused by the buildup of ice and snow along roof edges and in valleys. Heat cable prevents ice dams & frozen gutters.
Heat Cable Prevents Ice Dams?
Yes, heat cable is very effective at preventing Ice Dams.
How much does it cost to run heat cable?
Costs will vary depending on the length of the cable
Temperatures you run the cable (colder temps take more energy)
A 100-foot heat cable run 12 hours a day at 32 degrees Fahrenheit will cost approx.. $1.44 per day
Where should I install Heat Cable?
North facing roof lines and valleys
Over sidewalks and garage doors
Known ice dam areas from previous experience
The heat cable must run through the rain gutter and downspout allowing the heated water to discharge on the ground.
Do I need heat cable zig zagged on the edge of the roof and in the raingutter?
If your roof had ice dams that caused water damage inside the attic or home, then you should zig zag the heat cable on the edge of the roof.
If you're not worried about ice dams on the roof but want to keep the rain gutter & downspouts from freezing and dripping onto the sidewalk or stairs then only install heat cable in the raingutter & downspout.
How far up from the edge of the roof should the heat cable be installed?
Most commonly we install heat cable 2 foot up from the roof edge
If not limited by available power, imagine a line drawn straight up from the outside wall and through the roof and run the heat cable to that point
What Kind of Heat Cable Do I need?
Self-regulating Heat Cable
Here in Bozeman, MT, Dovetail Raingutter only installs self-regulating cable available in 120 or 240 volts. It comes on 1000-foot spools.
We cut the heat cable to the desired length for your heat cable installation.
While it’s pricier than options from the local hardware store, we believe it’s a safer and more efficient heat cable.
Self-regulating cable adjusts its heat output based on the surrounding temperature, and thanks to its self-regulating feature, it can safely overlap itself and be spliced without issue.
Non-regulating Heat Cable
A cheaper option and is available in various lengths at local hardware stores. It’s important to carefully measure the length you need to avoid having extra cable that could end up coiled on itself or being too short.
This type of cable always produces the same amount of heat, and manufacturers caution that it can burn out if it overlaps or is covered by leaves.
This type of heat cable cannot be spliced or cut to length.
Can I plug the heat cable into my electric outlet?
A 20-amp outlet can power a 165-foot, 120-volt cable when plugged in at temperatures of 32 degrees Fahrenheit or higher.
A 15-amp outlet can power a 125-foot, 120-volt cable when the temperature is 32 degrees Fahrenheit or higher.
For longer cable runs, a 220-volt cable can be used, but it will require a new electrical circuit installed by a licensed electrician.
When Should I Run My Heat Cable?
Run the cable when snow and ice are present between 20- and 40-degrees Fahrenheit
The heat cable can be connected to a thermostat that activates it when the temperature is set between roughly 20 and 40 degrees.
Additionally, a sensor can be installed in the gutter, ensuring the heat cable stays off when no moisture is detected.
good info here, hope we don’t have any ice dam problems this year!