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Roof heat cable is laid in a zig-zag above the eave, so a foot of roof edge takes several feet of cable. The Roof Heat Tape Calculator follows EasyHeat's sizing method for its ADKS roof and gutter de-icing cable (Emerson catalog, October 2017): roof edge × an overhang multiplier — 4.0 for a 12 inch overhang with a gutter or 3.0 without, 5.3 for 24 inches, 6.8 for 36 inches — plus the distance around each dormer, 6 ft per valley and twice the length of each downspout. EasyHeat's own example, 32 ft of roof with a 12 inch overhang and gutter, one 30 ft dormer, one valley and two 10 ft downspouts, needs 204 ft, and the 200 ft kit is chosen because it is within 5 ft. Pre-terminated kits come in 20 to 240 ft lengths and draw 5 W per foot, so 200 ft is 1,000 W and about 8.3 amps. HomeAdvisor's roof snow removal guide (June 2026) prices heating cable at $1–$6 per linear foot and installation at $12–$20 per linear foot. Running cost uses EIA's 2025–26 winter electricity price of 17.3¢ per kWh.
Sizing follows EasyHeat’s ADKS roof and gutter de-icing cable catalog (Emerson, October 2017). Cable and installation prices are from HomeAdvisor’s roof snow removal guide (updated June 2026); running cost uses EIA’s 2025–26 winter electricity price.
| Overhang | With gutter | No gutter | 40 ft of eave (gutter) |
|---|---|---|---|
| 12 in or less | 4.0 | 3.0 | 160 ft |
| 24 in | 5.3 | 4.3 | 212 ft |
| 36 in | 6.8 | 5.8 | 272 ft |
| 48 in | 8.1 | 7.1 | 324 ft |
| 60 in | 9.6 | 8.6 | 384 ft |
| 72 in | 11.2 | 10.2 | 448 ft |
EasyHeat's method for its ADKS roof and gutter cable: multiply the length of roof edge by an overhang multiplier (4.0 for a 12 in overhang with a gutter, 5.3 for 24 in, 6.8 for 36 in; 3.0, 4.3 and 5.8 without a gutter), then add the distance around each dormer, 6 ft per valley and twice the length of each downspout. Their worked example — 32 ft of roof, 12 in overhang with gutter, one 30 ft dormer, one valley and two 10 ft downspouts — needs 204 ft.
Pre-terminated cable cannot be cut or spliced, so choose the kit at or above your length (ADKS kits run 20, 30, 60, 80, 100, 120, 160, 200 and 240 ft). EasyHeat's own example picks the shorter kit when it is within 5 ft of the estimate, as with 204 ft → the 200 ft kit.
Constant-wattage residential cable such as ADKS draws 5 watts per foot. A 200 ft run is 1,000 W, about 8.3 amps at 120 V, and costs about 17¢ an hour at EIA's 17.3¢/kWh. A thermostat or snow-and-moisture control that only runs it when needed cuts that sharply.
HomeAdvisor's roof snow removal guide (June 2026) prices heating cable at $1–$6 per linear foot for the cable and $12–$20 per linear foot installed. EasyHeat notes the NEC requires ground-fault equipment protection (GFEP) on de-icing cable, so plan on a protected outdoor outlet.
It keeps channels open so meltwater can drain off the eave and through the gutters and downspouts. It does not melt the whole roof, and EasyHeat says not to use it to clear snow and ice that has already built up. The lasting fixes are air sealing, attic insulation and ventilation, with ice and water shield under the shingles at the eaves.
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