Nonprofit, nonpartisan journalism. Supported by readers.


Should you install heat cables to prevent ice dams?

Heat cable

Heat cable, heat tape, heat wire…they’re different names that mean the same thing. They’re hot wires that run up and down your roof to melt snow and prevent ice buildup on your overhangs and in your valleys.

Heat cable has its place in the world (more on that in a minute), but I usually don’t recommend it to my customers, for a few reasons:

Heat Cable Problem #1: It’s often a Band-Aid.

Heat cable doesn’t fix the root cause of the problem: too much snow on a roof that’s overheated because warm air is leaking into your attic.

90% of the time that problem is fixable, and it all starts with a quality home energy audit from someone who understands insulation, ventilation, and ice dams. You’ll probably be urged to seal up spaces where warm air is sneaking into your attic – like around light fixtures, outlets, etc. These areas that allow air-leaks into your attic are called “attic bypasses.” Your energy auditor may also tell you to double down on your insulation, or to improve your ventilation, or both

Heat Cable Problem #2: It’s an energy-drainer.

Even very good heat cable may add about 20% to your energy bill – all depending on how often you power it on. That’s no better on your wallet than it is on the environment. (If I’m going to incur the wrath of Al Gore, at least I’d want it to be because I’ve got the showiest Christmas lights in the neighborhood.)

Some homeowners forget to turn off the heat cable. They accidentally keep it powered on throughout the warmer months, wasting more energy and money. This also wears out your heat cable much faster. Most heat cable doesn’t even last long to begin with; the average life of heat cable seems to be around 3-5 years. Again…this depends on a number of factors.

(Side note: Apparently they now make a type of heat cable that turns on and off automatically. But I don’t trust most technologies that just came out of the laboratory, and even if the heat cable shuts off in the spring it still poses problems in the winter.)

Heat Cable Problem #3: It melts snow that can just refreeze.

Anything that melts snow on your roof can cause an ice dam. The cables will create lots of zig-zagging channels of melted snow across your roof. Where does that melted snow go? Well, it’ssupposed to roll down the slope of your roof and end up on the ground. But in many cases it ends up refreezing along the edge of your overhangs, or refreezing just above the heat cable. How do I know this? Because not only did we install heat cables many years ago, but also every year we’d remove dozens of ice dams on homes with heat cable installed.

Heat Cable Problem #4: The warranty is a joke in most cases.

Sometimes heat cable installers will try to sell you on heat cable by telling you there’s a “great warranty!” What they don’t tell you is that warranty typically pertains to parts only, and that the parts (the cable and tape) are dirt-cheap. The labor makes up most of the installation cost. Look for a parts-and-labor warranty. There’s a good chance you’re not going to find it, because heat cable inherently doesn’t last long, especially with heavy use.

If you do find a parts-and-labor warranty, make sure it’s being offered by a company that’s been around longer than your favorite pair of socks.

Last but not least, ask the installer what happens if the heat cable does not work and you still end up with ice dams. (Their answer may just prove my point.)

Heat Cable Problem #5: It’s ugly.

Even if a heat cable functioned perfectly, it’s still ugly. You might as well wear Crocs while you’re at it.

Why do people take down their Christmas lights each year? Because your home looks sad and disheveled if you’ve a bunch of unused wires hanging all over it.

But unlike Christmas lights, heat cable is not something you’ll remove and reinstall each year. It’s semi-permanent. It will be on the prominent parts of your roof – your overhangs valleys – staring you in the face 365 days a year.

We know what a pain heat cable is. We used to install it.

Homeowners asked us about heat cable all the time, in the early days. Everyone wanted what seemed like a quick, easy, cheap solution to the ice dam problem.

But we had to stop. We just had too many problems with heat cable – the ones I’ve told you about. I don’t like offering any service that doesn’t provide high value for the money, and although it was a very profitable business we got out of it altogether.

As an ice dam removal pro, I’m in the business of helping my customer solve problems, and in many cases heat cable was creating problems.

When is heat cable appropriate?

If you were reading pretty closely you might have noticed I said “I rarely recommend heat cable.” Believe it or not, sometimes it’s the only option, and it can be effective.

Some homes have design flaws, and sometimes the cost to correct the design flaw is just too high. Some houses are ice-dam magnets, and nothing will keep the ice dams away. In that case, heat cable can help you keep trouble spots clear of snow and ice.

But you probably don’t live in that house. You should only try heat cable as a last resort. This means you’ve done the energy audit, you’ve had the insulation guys out, you’ve had your ventilation checked, you’ve sealed up any air leaks into your attic, and you’re raking your roof whenever the snow starts to pile up. A cool and clean roof is the best way to prevent ice dams.

On the off-chance you’re still getting ice dams after all that, then yes, maybe you should have heat cable professionally installed on those trouble spots. Just know that it’s a last resort, and still doesn’t always do the trick.

We remove more ice dams per year than probably any other company on the planet. Many of those ice dams are on homes with heat cables. I can’t in good faith suggest you install heat cables on your roof, unless you’ve tried every other prevention measure first (which will probably work).

This post was written by Joe Palumbo and originally published on Ice Dam Guys Blog. Follow Joe on Twitter: @icedamguys.

If you blog and would like your work considered for Minnesota Blog Cabin, please submit our registration form.

Comments (6)

  1. Submitted by Josh William on 11/10/2015 - 09:56 am.

    Ice damns are no fun

    My last house had a huge problem with ice dams. Had to pay my deductible for water damage mitigation. It was NO fun. In addition to the cost of dam removal. The house had a design flaw: vaulted ceilings. I couldn’t add any more insulation under the edges since there was lack of clearance in the attic.

    The best investment I made: a roof rake. It’s not fun to rake a 2 story house when it’s -10 outside, but it seriously gets the job done. Most hardware stores sell them.

    If I was going to be out of town for a lengthy amount of time in the winter, I would fill tube socks with salt and lay them near the roof edge to channel melting snow/ice/water.

  2. Submitted by Pat McGee on 11/06/2015 - 12:04 pm.

    Ugh. Ice dams.

    We’ve done everything the professionals told us to do except for turning the house around so the ice dam addicted front of the house faces south instead of north. Having heat cables installed was cheaper. And, anyway, our city wouldn’t let us move the front to the back even if we could have afforded it. Would have violated zoning regulations.

  3. Submitted by Joe Palumbo on 11/06/2015 - 05:26 pm.

    Ice dams are no fun indeed

    Josh and Pat, thanks for your comments.

    Glad to hear you’re raking your roof. Nothing keeps ice dams away like a roof rake!
    If you’re going to be out of town for a significant length of time, and if no people or pets are in the house, I would recommend keeping the heat as low as possible so that the attic doesn’t warm up much or at all.

    I take it you raked your roof, too?

  4. Submitted by Bob Manske on 11/06/2015 - 04:33 pm.

    Heat Cables

    Hi Joe, Its good to see you respond quickly to postings. I was disappointed by your review of heat tape. Two Items in your post beg for clarification: 1. Installing cable in the gutter channel and downspout provides a clear channel for roof drainage; 2. Automatic water sensing switches provide for electricity to the cable only when it is needed…when the roof is warm enough to melt. These two additions make the cable an economical fix for old houses with inherent design flaws, like my 1.5 story bungalow expansion style home. Placement of cable in the gutter and downspout do provide an additional annoyance in clearing leaves and seeds; however, it beats the heck out of the backups and leakage damage from ice dams. I previously used a roof rake but that doesn’t work on a second story shed dormer nor does it work when you take extended winter vacations. Thanks for the post.

    • Submitted by Joe Palumbo on 11/06/2015 - 10:23 pm.

      Sorry that you were so disappointed in my review of heat-cable Robert. 17+ years of removing ice dams has taught me a lot – much of which homeowners disagree with.

      Gutters almost never “cause” ice dams. Therefore wether your gutters are kept free of ice, or….completely removed from your home altogether, it won’t have any impact on the development of ice dams.

      Automatic water sensing switches are hugely prone to failure. I’ve seen countless switches such as these fail. They either cause the heat cable to stay on constantly (jacking your electric bill through the roof), or the failed switch cuases the heat cable to remain OFF, potentially causing snow and ice buildup.

      Heat cables (and the fancy switches) are typically a waste of money, and another problem waiting to happen. And…even when they do work, “eventually” the cable or switch will go bad leaving you with surprise ice dams and enteror water damage. For this reason, along with many others, we no longer install them. It’s much better to encourage people to fix the underlying problems and/or rake their roof religiously.

      Although uncommon, there are instances when heat cable is the magic bullet, and it works flawlessly for many years. It sounds like you may be one of those instances, and I’m pleased that your the “one in a thousand” that got lucky.

      Thanks for the feedback Robert. It’s always fun to chat with others!

  5. Submitted by Patricia Huffman on 01/19/2019 - 12:32 am.

    Hi, I moved into a mobile home that has heat tape for ice dams, i know nothing about heat tape but it doesn’t reach the outdoor plug so i guess i use an extension cord? or is there a special cord i need. It looks like i need an extension cord for each end of house? i see a plug in the back side of house and in the front side of house.

Leave a Reply