Heat Tape

Heat tape (also called pipe heating cable or heat cable) is an electrically resistive cable wrapped around water pipes to add enough warmth to prevent freezing during cold weather. Unlike pipe insulation (which only slows heat loss), heat tape actively generates heat — making it the reliable solution for pipes in truly exposed, unheated spaces like crawl spaces, exterior walls, garages, and pump houses in cold climates.

Types of heat tape

• Self-regulating heat cable (preferred): uses a conductive polymer core that automatically increases heat output as temperature drops and reduces it as temperature rises. Energy-efficient, can be overlapped without overheating, runs continuously without a thermostat needed. Cost: $1–$3 per linear foot.
• Constant-wattage heat cable: older technology — outputs a fixed wattage regardless of temperature. Should never be overlapped. Requires a thermostat to prevent overheating and reduce energy use. Less expensive upfront but more costly to operate.
• Thermostat-controlled heat tape: either type above with an integrated or external thermostat that activates only when temperatures approach freezing (typically set to 35–40°F). Reduces energy consumption significantly.

Installation

Wrap heat cable in a spiral pattern around the pipe (self-regulating) or in a single pass alongside the pipe (constant-wattage). Cover with pipe insulation over the tape to trap the heat close to the pipe. Plug into a standard 120V GFCI outlet (heat tape in damp locations requires GFCI protection). Inspect cables annually for damage — cracked insulation on heat tape is a fire hazard.

Limitations

Heat tape fails eventually — most products are rated for 3–5 years. Cracked or damaged heat tape is a leading cause of pipe-area fires. Replace proactively on a schedule, and always use UL-listed products. For pipes with continuous freeze risk, a better long-term solution may be repiping to move supply lines to conditioned space.