Best Heat Tape for Pipes: Length, Cost, Safety | Curb Calc

Heat tape for pipes: buy the cable as long as the pipe, never overlap a thermostat cable, what 12 to 30 ft costs a day, CPSC fire rules, two picks.

11/7/20264 min read

Curb Calc cover titled Best Heat Tape for Pipes, with a photo of an outdoor tap and basin encased in ice, a FREE CALCULATOR badge, a callout that a 24 ft 168 W cable costs 73 cents a day if it heats nonstop, and a table of hourly and daily cost for 12, 24 and 30 ft cables.Curb Calc cover titled Best Heat Tape for Pipes, with a photo of an outdoor tap and basin encased in ice, a FREE CALCULATOR badge, a callout that a 24 ft 168 W cable costs 73 cents a day if it heats nonstop, and a table of hourly and daily cost for 12, 24 and 30 ft cables.

Last January your kitchen tap coughed air and nothing else: the supply pipe on the crawl space wall had frozen. A 24 ft heat cable on that pipe costs about 73 cents a day, even nonstop. The catch: Frost King warns cable doubled over itself can overheat, and a 1989 CPSC alert tied heat tapes to some 3,300 home fires a year.

Quick pick: Frost King HC24A for a 24 ft pipe; its kits run 3 to 30 ft, so match your pipe.

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An outdoor tap on a dark post with its basin encased in ice and icicles in a snowy pine forest
An outdoor tap on a dark post with its basin encased in ice and icicles in a snowy pine forest

Photo: Murat Halıcı on Pexels

Thermostat cable or self-regulating?

Thermostat: Frost King's kits put out 7 W per foot. Its FAQ says the thermostat turns on below 38°F at the pipe and off above 45°F.

Self-regulating: Raychem's Frostex data sheet says output rises as the pipe gets colder and falls as it warms, about 3 W per foot at 50°F.

Overlap: Frost King says never wrap or spiral it, and never double it back. Raychem runs Frostex straight along the pipe, not spiraled. Follow your sheet.

Roof ice takes a different cable: best heat cable for gutters.

A plumber's hands working a copper pipe held in a bench vise
A plumber's hands working a copper pipe held in a bench vise

Photo: Yudi Ding on Pexels

How much heat tape you need

Thermostat cable: pick the kit from Frost King's chart by pipe length and diameter, never longer than the pipe. On 1 to 1½ in. pipe many lengths take two cables; the sheet puts their extra ends on opposite sides of the pipe.

Self-regulating: Raychem's table counts straight runs by pipe size, insulation and coldest night. A 1/2 in. metal pipe under 1/2 in. insulation: one run to 0°F, two at -20°F.

Limits: Frost King's thermostat kits top out at 30 ft; Frostex allows 50 ft per plug.

A two-outlet receptacle in a metal box on a brick wall, with conduit along the mortar line
A two-outlet receptacle in a metal box on a brick wall, with conduit along the mortar line

Photo: Benjamin Farren on Pexels

What it costs to run

At 18.16 cents per kWh, the U.S. home average for August 2026 (EIA), heating nonstop:

12 ft, 84 W: about 37 cents a day.

24 ft, 168 W: about 73 cents a day, $22 a month.

30 ft, 210 W: about 92 cents a day.

Ceilings, not averages: the thermostat shuts off above 45°F.

A gloved worker pressing pink insulation between wall studs
A gloved worker pressing pink insulation between wall studs

Photo: Erik Mclean on Pexels

Fire safety rules

Every fall: CPSC says unplug it and check the full length for cracked or charred insulation and bare wires.

Insulate: Frost King's sheet says 1/2 in. fiberglass or other non-flammable wrap with a vapor seal. CPSC: never wrap tape over insulation, and cover it only as the maker allows.

Tape: rated 176°F or more, every 6 inches (Frost King).

GFI outlet: Frost King's install guide says plug into one. Frostex's plug has ground-fault protection built in.

Never: in walls, floors or ceilings, buried, or on drain lines, fuel lines or hoses (Frost King).

Water dripping from a taped joint on a white plastic pipe outdoors
Water dripping from a taped joint on a white plastic pipe outdoors

Photo: Swastik Arora on Pexels

Plastic pipe, mobile homes, frozen now

Plastic: Frost King's FAQ allows only Schedule 40 supply pipe, 3/8 to 1½ in., yet says its kits aren't made for PVC. PVC, PEX or unsure? Choose a cable whose data sheet lists plastic pipe, like Frostex.

Mobile home feed line: Frost King says no, too flexible. Frostex's data sheet lists it for mobile home pipe heating.

Frozen now: thaw it first: how to thaw frozen pipes. Outside faucet: when to turn off outdoor faucets.

Hands fitting a brass union on a steel pipe beside foil-faced insulation
Hands fitting a brass union on a steel pipe beside foil-faced insulation

Photo: Anıl Karakaya on Pexels

Heat tape for pipes (#ad)

As an Amazon Associate, Curb Calc earns from qualifying purchases.

Frost King HC24A Heat Cable Kit, 24 ft: 7 W per foot, 120V; Frost King says the thermostat is built in. See it on Amazon

Frost King HC12A Heat Cable Kit, 12 ft: for metal and plastic water pipes, to -40°F, per the listing. See it on Amazon

You'll also need 1/2 in. fiberglass pipe wrap with a vapor seal and tape rated 176°F (Frost King's sheet).

Copper pipes joined at a tee fitting against a black background
Copper pipes joined at a tee fitting against a black background

Photo: Magda Ehlers on Pexels

Heat tape FAQ

Does heat tape for pipes need insulation?

Frost King says yes, 1/2 in. fiberglass with a vapor seal; CPSC says non-flammable only.

Can heat tape overlap?

Not Frost King's: it says never double it up, even on a short section. Other cables: check the sheet.

How much does heat tape cost to run?

A 24 ft, 168 W cable costs about 73 cents a day if it runs nonstop.

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Sources: CPSC alert, 1989; Frost King FAQ; Frost King sheet; Frost King install guide; Raychem Frostex data sheet; EIA Table 5.6.A.