How Long Should Roof Heating Cables Stay On?

One way to prevent snow and ice from becoming a hazard on your property and to prevent ice dams from forming is to install roof heating cables (also called deicing cables). These cables can be turned on during winter storms and kept on until all snow and ice on the roof has melted off.

You can turn your cables on before a snow or ice storm is forecast to beging, and leave them on until the build-up on your roof melts and drains off, which can take a few hours, depending on how much snow or ice has collected on your roof. It is unnecessary to keep the cables on all of the time. Doing so will have no beneficial effect on your home and will run up your energy bill.

You can also turn off your cables once the outside temperature is at or above 35-40 degrees Fahrenheit (approx. 4 degrees Celsius).

What Are Roof Heating Cables And What Are They Used For?

In short, roof heating cables prevent snow and ice from building up on your roof. They attach to the outer edges of your roof and keep the shingles warm. They allow snow and ice to melt and, ideally, drain more quickly.

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When these cables perform as intended, they can prevent damage to your roof or leaks inside your home.

What Are Roof Heating Cables, and What Are They Used For?

Why Is It So Important to Remove Snow and Ice?

The weight of snow or ice on your roof, especially after a big storm, can put significant pressure on your roof. This could lead to leaks, which can cause damage to the interior of your home.

In addition, when hot air inside your home melts snow and ice on your roof, they can form ice dams. Ice dams result when water runoff from your roof refreezes along the edges. This ice can build up and ultimately prevent water from draining off your roof.

When Should Heating Cables Be Turned On?

If you’ve already installed your cables or had a professional come install them for you, the next step is understanding how to operate them.

Roof heating cables are attached to the eaves, or edges, of your roof where water runoff is most likely to freeze. The best way to use your cables is by turning them on before they’re needed.

For example, turn them on a few hours before a winter storm is scheduled to hit. Then, once the storm passes and the snow has melted, you can turn them off. However, if water has already created an ice dam on your roof, you can turn on the cables to melt the ice that has collected there.

When Should Heating Cable Be Turned On?

When Should You Purchase Roof Heating Cables?

While a roof de-icing system is a good option in many cases when it comes to preventing ice dams, there are a couple of things you can do before investing in heating cables.

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Check Your Insulation

The temperature at the center of your roof is a function of the how warm your home is. Ice dams can form when hot air from your attic that warms the center of the roof does not reach the edges. If your home is poorly insulated, it could cause excess heat to collect in your attic.

Taking the time to install proper insulation will help keep the cold air out and the warm air in.

Check For Ventilation Leaks in Your Home

There are several reasons hot air from your home could be making its way into your attic. One of the main drivers are small air gaps within your main living areas.

Gaps around light fixtures, electrical outlets, and where cables or plumbing run through walls can all cause ventilation leaks. Sealing up these gaps and improving ventilation overall can not only help prevent the formation of ice dams – it may mean you don’t need heating cables in the first place.

If you’ve thoroughly insulated your attic and sealed up any air gaps in your home, but still see ice dams, then heating cables might be the right call. Of course, you can install them yourself, but calling a professional is also a good option.

When Should You Purchase Roof Heating Cables?


Here are some common questions regarding roof heating cables.

What Are the Risks of Roof Heating Cables?

Depending on how long you leave your cables on, your energy costs could be pretty high. In addition, if you turn them off too soon, ice dams could still form.

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What Happens if I Leave My Cables On?

In most cases, leaving your cables on for extended periods is unnecessary but will not cause damage. However, if you regularly leave your cables on too long, they can wear out sooner.

Can I Buy Cables That Turn Off Automatically?

Some cables have an option for an automatic shutoff. This feature can be beneficial because it will help ensure your cables aren’t left on too long. It will also help minimize energy bills.

Roof heating cables can be a great choice if you live in an area frequently hit by winter storms that easily cause snow and ice to build up on your roof.

However, it is important to understand the limitations and how to properly use the cables. Be sure that you don’t turn them on too late, don’t leave them on too long, and regularly check your roof for ice dams that might have formed despite the presence of the cables.

How Much Do Roof Heating Cables Cost?

According to Cost Owl, a basic roof heating cable (with no thermostat), costs less than $1.00 per linear foot. A heating cable thermostat can be purchased on its own for $75 – $200+. You will of course also have to factor in labor costs if you hire someone to install your cables.


Roof heating cables can be a vital tool for your home when the weather gets cold. Be sure to turn them on before a cold storm or anytime you are expecting a lot of ice in the area, but keep them off as much as possible the rest of the time.