For one short section of pipe that freezes every winter, buy a plug-in heat cable in the length that matches the pipe, such as Frost King’s HC kits. For long runs or plastic pipe, choose a self-regulating cable, which lowers its own output as the pipe warms. Either way, plug it into a GFCI-protected outlet and follow the U.S. Consumer Product Safety Commission’s rules on what may cover it.
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Our pick: the Frost King HC plug-in heat cable, in the length that matches your pipe. Check the Frost King HC6A on Amazon
Heat tape — also sold as heat cable or pipe heating cable — is an electric heater you run along a water pipe so it cannot freeze. It is the fix for the pipe that insulation alone cannot save: a line in an unheated crawl space, along a garage wall, under a mobile home, or one that has frozen before. The American Red Cross lists “UL-listed heat tape” and pipe sleeves as the products to consider for exposed water pipes. The choice comes down to two types of cable and one set of safety rules.
Heat Tape Compared
| Cable | Best for | Type and output |
|---|---|---|
| Frost King HC6A | Best Overall | Plug-in, fixed length · 7 W/ft |
| HEATIT 30 ft | Best Self-Regulating | Self-regulating + thermostat · 3 W/ft |
| HEATIT HTM-100 | Best for Mobile Homes and Long Runs | Self-regulating bulk, cut to fit · 3 W/ft |
All specs above come from each product’s Amazon listing as read on September 23, 2026.
Best OverallEditor’s Choice
Frost King HC Automatic Heat Cable Kit
plug-in 120V pipe heating cable · 7 W/ft · keeps water flowing down to −40°F · for metal and plastic water pipes · fixed lengths (Amazon sells 3, 6, 9 and 12 ft) · the listing linked here is the 6 ft HC6A (all per the listings)
Check the Frost King HC6A on Amazon →
For one short section of pipe that freezes every winter — a line along a garage wall, a run to an outdoor spigot, a stub in a crawl space — a plug-in kit sold in a fixed length is the simplest answer. The listing describes the Frost King HC6A as an automatic 120V heating cable at 7 watts per foot that keeps water flowing down to −40°F, for metal and plastic water pipes. You buy the length that matches the pipe; Amazon sells the same kit as the 3 ft HC3A, the 9 ft HC9A and the 12 ft HC12A.
Fixed-length cable is not cut to fit. The Frost King instruction sheet says to run the cable straight along the pipe, never wrapped or spiraled, and never to let it touch, cross or overlap itself at any point. It also says never to use a cable longer than the pipe, never to install it in walls, floors or ceilings, never to bury it or let it touch the ground, not to use it on drain lines, fuel lines or hoses, and to wrap the finished job in 1/2 inch fiberglass insulation and never more than that. On plastic pipe, the sheet allows the cable only if the pipe is filled with water at all times. On its website Frost King also says not to use these kits on a mobile home feed line. Read the kit’s own sheet for how it goes on the pipe and what may cover it.
- Plug-in kit in fixed lengths from 3 ft, so a short problem section does not need a long cable.
- The listing rates it to keep water flowing down to −40°F.
- Made for metal and plastic water pipes, per the listing.
- Fixed length: it cannot be cut, so measure the pipe before you order.
- Listed at 7 W/ft, against 3 W/ft listed for the self-regulating cables below.
- Needs a grounded, GFCI-protected outlet within reach (CPSC guidance).
Verdict: Best for one short, known trouble spot where you can plug in close by.
Best Self-Regulating
HEATIT Self-Regulating Pipe Heating Cable (30 ft)
self-regulating cable · 3 W/ft · built-in thermostat on at 38°F, off at 50°F · maintains water flow down to −40°F · metal and plastic pipe (copper, PVC, stainless) · ETL certified end to end, UL-certified plug · 2 ft power cord · lengths 3 to 160 ft (all per the listing)
Check the HEATIT 30 ft self-regulating cable on Amazon →
A self-regulating cable adjusts its own output: as the pipe warms, the cable puts out less heat. The HEATIT listing describes exactly that, at 3 watts per foot, with a built-in thermostat that switches the cable on at 38°F and off at 50°F, so it draws power only when the pipe is near freezing. The listing gives it as ETL certified end to end with a UL-certified plug, rated for metal and plastic pipe including copper, PVC and stainless, and holding water flow down to −40°F. It comes in lengths from 3 ft to 160 ft; this link is the 30 ft cable.
That lower wattage and self-limiting output make self-regulating cable the easier fit for longer runs and plastic pipe. It is still a plug-in heater on your water line, so the CPSC rules below apply to it just the same, and the instruction sheet in the box controls how it goes on the pipe.
- Self-regulating output plus a thermostat that runs it only between 38°F and 50°F, per the listing.
- Listed at 3 W/ft, less than half the 7 W/ft listed for the Frost King kit.
- ETL certified end to end, with lengths from 3 to 160 ft.
- Sold in fixed lengths; the HEATIT JHSF manual sizes its cable from a chart that can call for more cable than pipe in cold climates. Follow the instructions in the box.
- Only a 2 ft power cord, so the outlet has to be close to the start of the pipe.
- Stops protecting the pipe in a power outage, like every cable here.
Verdict: Best for longer runs and plastic pipe where you want the cable to back off on its own as the pipe warms.
Best for Mobile Homes and Long Runs
HEATIT HTM Self-Regulating Heat Cable, 100 ft Bulk (HTM-100)
100 ft bulk self-regulating cable · 3 W/ft · for mobile homes and other dry locations · residential metal or plastic supply and drain pipes · tinned copper braid jacket that doubles as the ground · ETL approved · connection kit sold separately (all per the listing)
Check the HEATIT HTM-100 bulk cable on Amazon →
Under a mobile home, the water supply and the drain can both run through cold air for a long way, and a fixed-length cable rarely matches the run. The HTM-100 is bulk cable: the listing describes 100 feet of self-regulating cable for mobile homes and other dry applications, for residential metal or plastic water supply and drain pipes, with a tinned copper braid that serves as both the outer jacket and the electrical ground. It can go on straight, spiraled or overlapped, according to the listing.
Bulk cable is a bigger job than a plug-in kit. The listing says the HEATIT HTM connection kit is required and sold separately, and lists glass cloth tape and fiberglass insulation among the materials you will need. The HEATIT HTM manual sets a maximum circuit length of 75 feet and warns that a longer length may cause the internal fuse to blow, so the 100 ft spool is cut down, not run whole. It also says to always use a ground fault protection device and never to use an extension cord, and in a mobile home to connect the plug only to an outlet underneath the home, in an unexposed, dry location, because the plug is not weatherproof. Follow the instructions that come with the cable and the connection kit. If you are not comfortable making up the power and end connections, this is the pick to have a pro install.
- 100 ft of bulk self-regulating cable, cut to the length of the run (75 feet maximum circuit length, per the HEATIT HTM manual).
- Rated by the listing for supply and drain pipes, metal or plastic.
- Tinned copper braid jacket doubles as the ground; ETL approved.
- The HTM connection kit is required and sold separately, per the listing.
- Making up the connections is more work than plugging in a finished kit.
- Listed for dry locations only.
Verdict: Best for mobile homes and runs up to 75 feet where a fixed-length cable will not fit the pipe.
Plug-In Thermostat Cable or Self-Regulating: Which Do You Need?
There are two families of pipe heating cable, and the difference is what happens to the heat once the pipe warms up.
- Fixed-output plug-in cable (like the Frost King HC kits) puts out a set wattage per foot whenever it is on. It is sold in finished lengths with the plug attached. Because the output does not drop, the cable must not cross or double back on itself: the Frost King sheet says never to let its cable touch, cross or overlap itself at any point.
- Self-regulating cable (both HEATIT picks) lowers its own output as the pipe warms, point by point along its length. The HTM listing says it can be run straight, spiraled or overlapped. That makes it the easier fit for long runs and plastic pipe.
For a single short section near an outlet, the fixed-length kit is simpler. For anything long, anything plastic, or a run that does not match a stock length, go self-regulating.
How Much Cable Do You Need?
Measure the pipe you need to protect, including the part that runs through the cold space and any valve on it. A cable laid straight along the pipe needs roughly the pipe’s length; a cable spiraled around the pipe needs more. The Frost King sheet forbids spiraling its cable; the HEATIT HTM manual allows a spiral wrap or a straight run. Where spiraling is allowed, the maker’s instructions set the spacing. Fixed-length kits cannot be cut. Do not round up with the Frost King kit: its sheet says never to use a cable longer than the pipe and not to oversize the cable, and that on 3/8 to 3/4 inch pipe the cable can be up to 2 feet shorter than the pipe. The HEATIT JHSF manual sizes its plug-in cable from a chart by pipe size, pipe material and lowest expected temperature; for the HEATIT cable you receive, follow the instructions in the box. Bulk cable is cut to length and finished with the maker’s connection kit; the HEATIT HTM manual sets a maximum circuit length of 75 feet. Do not guess the spacing on a spiral wrap; use the chart in the cable’s own instructions.
Heat Tape Safety: What the CPSC Says
Heat tape is an electric heater left running in a crawl space or attic, unattended, for months. In its 1996 heat-tape guidelines, the U.S. Consumer Product Safety Commission estimated about 1,500 fires, 10 deaths and 100 injuries a year from faulty electric heat tapes, and said newer tapes certified to national safety standards have a much better record than old ones. Its guidance, in short:
- Replace uncertified heat tape more than 3 years old with tape certified to UL, CSA or FMRC standards.
- Plug the 3-prong plug into a grounded 3-prong outlet protected by a ground-fault circuit interrupter (GFCI).
- Put the tape directly on the pipe, never on top of the insulation.
- Do not wrap the tape over itself unless the manufacturer’s instructions allow it.
- Do not cover it with insulation unless the manufacturer advises it; where a cover is allowed, use non-flammable insulation such as fiberglass, not foam or vinyl.
- Keep the end cap sealed and off the ground, and do not use water-pipe heat tape on gutters, driveways or fuel lines.
- Inspect it every year and replace it if you see discoloration, charring, cuts, breaks in the insulation or bare wire.
That fourth and fifth point matter most if you already have foam sleeves on the pipe: on the section you heat, the cable goes on bare pipe, and the covering is whatever the cable maker specifies.
Heat Tape vs. Pipe Insulation
They do different jobs. Insulation slows heat loss, so it protects a pipe only while the pipe still has heat to lose; the Red Cross recommends insulating both hot and cold pipes in unheated areas. A heat cable adds heat, so it protects a pipe with no warmth behind it. Most homes need insulation everywhere exposed and a cable only on the one or two sections that freeze anyway. Start with our pipe insulation picks, and see the winterizing checklist for the rest of the fall routine.
FAQ
Can heat tape go on PEX or other plastic pipe?
Only if its listing or instructions say so. All three cables on this page are listed for metal and plastic water pipe: the Frost King HC kits “for metal and plastic water pipes,” and both HEATIT cables for metal or plastic pipe. The Frost King instruction sheet allows plastic pipe, PEX included, only when the pipe stays full of water, while the FAQ on its website names only Schedule 40 plastic. Check the instructions for the exact model before you buy.
Should heat tape stay plugged in all winter?
A cable with a built-in thermostat is designed to stay plugged in and switch itself on only in the cold; the HEATIT listing gives its thermostat as on at 38°F and off at 50°F. CPSC advises inspecting heat tape every year and replacing it if you see discoloration, charring, cuts or bare wire. The Frost King sheet says to inspect its cable at the start of the heating season and monthly during operation.
Can I put pipe insulation over heat tape?
Only if the cable’s manufacturer says you can. CPSC advises against covering heat tape with insulation unless the manufacturer advises it, recommends non-flammable insulation such as fiberglass where a cover is allowed, and says not to use foam or vinyl insulation that could catch fire if the tape fails.
Does heat tape work in a power outage?
No. Every cable here is a 120V electric heater, so it stops the moment the power does. For a house left empty in winter, pair it with a freeze alarm and a plan to shut off and drain the water if the power goes.
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Bottom Line
For one short trouble spot near an outlet, buy the Frost King HC kit in the length that matches the pipe. For a long run or plastic pipe, the self-regulating HEATIT 30 ft cable. Under a mobile home or on a run no stock length fits, the HEATIT HTM bulk cable with its connection kit. Whichever you buy, install it by the instructions that come in the box, which control, and follow the CPSC rules: GFCI outlet, cable on bare pipe, no foam over it, and a look at it every fall. If a pipe is already frozen, see how to thaw frozen pipes first.
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