Updated: May 18
If you want to avoid the catastrophe of ice dams forming on your roof during the cold winter, heat trace cable is your best option. Self-regulating heat cable increases conductivity as temperatures drop, making it a great choice for efficiently keeping your roof and gutters free of damaging ice buildup in winter.
But once you’ve decided to get heat cable installed on your home or business—or to install it yourself—you’ll need to decide which brand to go with. There are many different heat cable manufacturers, but not all of their products are equal. To help you narrow down the options, we’ve come up with a list of differentiators.
To create this list, we’ve drawn on our many years of installing different brands of heat cable—some with poor results, others with stellar results. We’ve noticed which features allow the cable to work most efficiently and hold up well over the years. We’ve also done our due diligence by performing a science experiment of sorts. This involved cutting into the different brands of heat cable, opening them up, and closely inspecting all of the features with a trained eye.
When you’re in the market for heat cable, consider the following:
1. Jacket. The outer polyurethane (PUR) casing, also known as the “jacket” of the cable, should be very thick and durable. You want that cable to be able to pull across sharp corners, gutters, and abrasive surfaces without getting punctured or torn. Drexan heat cable, which is our favorite brand, has a particularly durable jacket. In fact, when we did the “cut test” on the Drexan cable, we had to go around it a few times with our knife just to be able to cut into it.
You should also make sure that the jacket is pliable. If the material is thick but brittle, it won’t be able to slide well around corners or bend in a new direction without cracking.
2. Air pockets. Remember this above all: air pockets are bad! Air in heat cable makes it less efficient. The more air is in a cable, the more heat the core of that cable will have to generate to get that heat radiating outward. This leads to “hot spots” that result in the cable overheating.
I can hold a piece of cable in my hand and feel if that cable is insulated by too much air. For maximum efficiency and durability, you want cable that does not have air pockets. Once again, Drexan leads out in this category. Drexan extrudes their cable in a vacuum chamber, which sucks the air out and results in an extremely tight, air-free, high-functioning cable that will last.
3. Ground braid. When we cut into cable for testing purposes, we want to be able to see the imprint of the ground braid on the interior of the jacket. This indicates a tight bond between the outer seal and the braid, which means no air pockets. You want a ground braid that is very clean and tight. Sometimes we see ground braids with a lot of inconsistencies—tight in one part, loose in another. Or other times, we see ground braid that is consistent but has too big of gaps in the weave. A clean, consistent braid without gaps will lead to heat cable transferring heat efficiently.
4. Bus wire. This uninsulated, unshielded, unjacketed single wire type of conductor should never be exposed, but in some cases, I have seen that it is not embedded well into the carbon core. If the bus wire were to separate from the carbon core, it wouldn’t conduct electricity and would allow for heat generation. This separation will lead to cold spots, which will undermine your heat cable. Make sure that the bus wire is embedded securely into the carbon core.
5. Warranty. Warranties on heat cable range from 2 to 10 years. Make sure the product you choose has a generous warranty.
6. Connection kits. Splices are often necessary, and that means you’ll need a connection kit, but not all heat cable brands come with high-quality connectors. Raychem, arguably the biggest name in self-regulating cable, is a solid product (aside from having a few too many air pockets, in our opinion). However, we steer clear of them because their connection kits are hard to work with. Because they’re not intuitive, we frequently see them installed incorrectly, which means that connections to go bad prematurely.
7. Cable length. For a 20-amp breaker and 120-volt circuit, Raychem cable length is 150 feet. If you go anywhere beyond that, your startup draw is going to trip the breaker if temperatures are below 30°F. In contrast, Drexan heat cable can go for 210 feet for the same amps/volts. That means you’ll get more coverage off the same amount of power with comparable heat output.
8. Testing. When reputable companies manufacture cables, they don’t just hook them up and make sure they work. They put them through rigorous testing. Leading companies will run them at max capacity, then power them down, then run them, then again, then power them down, etc., to see when they start breaking down. If you check their ratings, you’ll see that Raychem breaks down after 1,100 cycles while Drexan continues to work for 1,800 cycles.
If you’re going through the work to install heat cable, or paying to have it installed, you want to make sure you’re starting with the best possible product. The last thing you want is for your heat cable to stop working in the middle of a cold patch or storm. While the best cables may cost more up front, they’re going to pay for themselves by lasting longer and giving you fewer headaches during their life cycle.