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What Is Heat Tape? How to Prevent Frozen Pipes

Everything to Know About Heat Tape and Cables

Heat tape installed on an outdoor pipe

The Spruce / Tessa Cooper

Heat tape can be a lifesaver in cold climates where water lines and hoses are exposed to freezing temperatures. When pipes freeze, the water expands and can rupture the pipes, potentially unleashing thousands of gallons of water into your home.

Insulating your pipes is essential and will prevent pipes from freezing in many situations. But it is not always enough during prolonged cold spells or when temperatures plummet into the sub-zero range. This is where heat tape—both the self-regulating and thermostat-controlled varieties—comes in to provide supplemental warmth as needed. Heat tape can work on pipes as a short-term solution if it is installed at the right time and in the proper way.

What Is Heat Tape?

Overhead view of coiled up heat tape

The Spruce / Tessa Cooper

Heat tape is an electrical cable, not an adhesive tape. Heat tape protects a vulnerable indoor or outdoor metal or plastic pipe to keep it from freezing. It is a flexible, flattened cable that typically plugs into a GFCI outlet. The heat tape should run along one side of the pipe or tightly wrap around a pipe in a candy cane pattern. Unless the instructions allow it, the tape should not be double-wrapped or overlapped or it could overheat and cause a short circuit.

Tip

The terms "heat tape" and "heat cable" are often used interchangeably, and the products serve the same function. There are more flexible varieties generally referred to as tape, as opposed to the stiffer cable-like varieties. Both can be suitable for wrapping around pipes.

Tips for Buying Heat Tape

Measuring a pipe for heat tape

The Spruce / Tessa Cooper

As you shop for the right heat tape for your project, here are some tips to keep in mind:

  • Consider a heat tape kit: If this is your first time installing heat tape, consider a kit rather than using raw cable to which you'll have to attach plugs. The kits typically come in just about any length you might need—from 3 feet to 100 feet. The plugs are already attached to ensure a proper connection.
  • Read the specifications: When selecting a heat tape, read the package to make sure it is appropriate for your application. Most heat tapes are approved for use on either plastic or metal water lines, but it's important to verify this before you buy. Also, make sure the product has the features you want, such as a power indicator light or a built-in thermostat.
  • Measure before buying: Take measurements of your pipes before you buy, so you have enough tape to complete your job. Remember that if you plan to wrap the tape in a spiral fashion around the pipe, the length of the tape will need to be considerably longer than the pipe itself.

Tips

Heat tape designed for plumbing pipes is similar to that used on roofs to prevent ice dams from forming along eaves. But the products are not always interchangeable. So be sure to read the package instructions to determine the approved applications.

Self-Regulating Heat Tape

Self-regulating heat tape can be cut to any length for a custom fit, or it can be purchased in kit form in a variety of lengths. The cable automatically varies its heat output according to changes in the surrounding temperature. It emits virtually no heat when temperatures are above freezing, and it increases levels of heat as temperatures drop. No manual temperature control is required.

You can buy self-regulating heat tape by the roll and sometimes even by the foot in many hardware and home improvement stores. In addition to the cable, you will need a connection kit with an end plug, as well as an accessible outlet to plug in the cable. If you buy self-regulating heat tape in a kit form at a specific length, the plug is generally already attached.

Thermostat-Controlled Heat Tape

Thermostat controlled heat tape

The Spruce / Tessa Cooper

Another type of heat tape is quite similar to the self-regulating variety, but it is regulated by a separate thermostat. So it requires a separate connection kit with a thermostat to control the temperature.

It, too, can be purchased by the foot or in a roll. It can be custom fit to your application because it can be cut to any size; plugs are then added to the ends of the cable. Thermostat-controlled heat tape is also available in kit form in various lengths with the plug and thermostat already attached.

Heated Water Hoses

A similar product to heat tape is a heated water hose. It can be useful for homeowners in transitional climates where periods of frost are limited and irrigation is still needed over the winter, as well as for filling livestock drinking tanks during the colder months.

Heated hoses come in many lengths and are designed with electrical conducting wires embedded into the rubber or vinyl walls of the hose. When these hoses are plugged in, an electrical current heats the hose all the way to the end. These hoses shut off automatically in warm weather to save electricity and prevent overheating.

How to Install Heat Tape

Installing heat tape on a pipe

The Spruce / Tessa Cooper

Heat tape is relatively easy to install, but you can hire a professional, too. If you have a large job or an area with lots of odd angles, you might want to consider calling in a pro.

If you're doing it yourself, carefully read and follow the manufacturer's instructions. Many types of heat tape are just attached to the underside of the pipe with electrical tape or zip ties. Other types are designed to be wrapped around the pipe in a spiral fashion. And some can be installed either way. Do not overlap the tape unless the manufacturer specifies that this is acceptable.

Heat tape is usually not used with pipe insulation, only if the manufacturer recommends it.

Another important point of the installation is the thermostat. It should be in the coldest area and directly on the water pipe itself to give an accurate reading.

FAQ
  • Will heat tape keep pipes from freezing?

    No method to keep pipes warm is foolproof, but heat tape works well to prevent pipes from freezing and bursting. As the temperature drops, the heat tape will warm to stop the water in the pipes from freezing.

  • How long does heat tape last on pipes?

    In general, heat tape only lasts for a few years. After that, it might not be as reliable, especially if it doesn't have much protection from the elements. Check your product manual to see when it recommends replacing the heat tape.

  • Will heat tape thaw frozen pipes?

    Even though frozen pipes often will thaw naturally, allowing frozen water to sit in pipes does increase the chance of a burst pipe. So heat tape can be applied to speed thawing and get the water running again. However, heat tape works best if it is placed on a pipe before the temperatures take a dive.