Not all heat cable is created equal

This is a guest blog post by Steve Kuhl of Radiant Solutions Company. This is the second in a three-part series.

Over the past 30 years, I've been asked countless times if heat cables are a good solution or a bad solution for ice dams. My answer has always been, "Yes". They are a great solution when you use the right cable and a bad solution if you don't. Heat cables are a controversial topic in the field of ice dam prevention for good reason. They can be inefficient, short-lived, ineffective and even pose a fire hazard in some situations.

But to be clear, all of these issues relate to installations involving a low-quality class of cables known as 'Constant-Wattage', which are usually bought on Amazon or at big-box retailers and installed by less-than-professional hands. Constant-wattage cable gets its name from the fact that--unlike self-regulating cable--it does not automatically adjust its energy consumption with changes in outdoor temperatures. It is hot, hot, hot, 100% of the time when plugged in. There are many other dubious distinctions described below.

Sadly, constant-wattage heat cable is the most widely used roof deicing cable in the country, accounting for roughly 90% of all residential installations and nearly 100% of all complaints. Based on my many years of experience in ice dam prevention and residential construction, my opinion on constant-wattage cable is clear: It is better to not install anything than to use these products on your home. This explains why 60% of the heat tape installations we do in the Minneapolis area involve tearing out constant-wattage and replacing it with self-regulating cable, even on systems less than a year old. Bummer.

Cost: A 100-foot constant-wattage cable will cost you around $75 whereas a self-regulating cable of the same length will be closer to $350. Ultimately, being cheap is the only short-term advantage constant-wattage cable has over self-regulating cable. Self-regulating cable is far cheaper over the long run when lifespans and energy consumption are factored in. If the cable feels very affordable, it is probably because it's cheap.

Dimension & Brand Names: How does the average person tell the difference between self-regulating cable and constant-wattage cable? Here are a few quick tips. Identifying constant-wattage cable visually is easy. It's normally black and round, measuring about ¼" in diameter and is usually sold under the brand names of Frost King, EasyHeat, Wrap-On or Heat-It.

Constant-wattage cables are typically the only option at local hardware stores both large and small. In contrast, self-regulating cables are normally ¼" x ½", similar in shape to standard Romex® wire used in American homes. For all of our installations, we use Heat Tape Pro, a commercial-grade self-regulating heat cable that carries a five-year manufacturer's warranty.

Performance & Limitations: A quick review of the manual and marketing materials will tell you quite a bit about constant wattage cable including these crucial limitations that few people are aware of:

Self-regulating heat cables were originally developed over 50 years ago for use in arctic oil fields to prevent pipelines from freezing. It's a robust technology with many years of proven effectiveness. It has a special conductive core that asks for more energy in response to cold and less when temperatures are warmer. In other words, it 'self-regulates'. Here are some benefits to self-regulating heat cables:

After all of these years in the ice dam, roofing and remodeling industries I still find myself coming back to this natural law in home maintenance: The solution is always about the budget. If you have a lot to spend you will choose one path, if you have a tighter wallet you will choose another. In terms of ice dams, I'm afraid there aren't always 'cheap' solutions. Homeowners must sometimes choose from the lesser of three evils: 1) Spend a lot on architectural enhancements, 2) Spend a lot on professional roof shoveling or risk a lot doing it themselves or, 3) Spend a fair amount on heat cables. The average self-regulating heat cable system we install in the Minneapolis area runs between $1,000 and $2,000.

My advice to anyone considering heat cable for ice dam prevention is to either install a high-quality, self-regulating heat cable or skip it altogether. Constant wattage heat cable is a total waste of money. Worse, it can create a false sense of security for people who have most likely already had a bad relationship with ice dams in the past.

Next week I will be writing a follow-up post that discusses how to install a long-lasting heat cable system, including design, materials, expected costs and installation tips.

Related post: Should you install heat cables to prevent ice dams?