Heat Pump Heat Strips: How They Work, Costs, and Efficiency Tips

Heat pump heat strips are electric resistance elements that provide supplemental heating when an air-source heat pump cannot meet the heating load, especially in cold temperatures. This article explains how heat strips work, when they engage, installation options, efficiency trade-offs, cost considerations, and best practices for U.S. homeowners seeking reliable, energy-conscious heating solutions.

Topic	Quick Summary
Purpose	Supplemental electric resistance heat for heat pumps
Types	Internal (in air handler) and external (auxiliary) heat strips
When They Run	During very low outdoor temps or during defrost cycles
Efficiency	Less efficient than heat pump core; useful for short-term or emergency heat
Typical Cost	$200–$800 for parts; $300–$1,200 installed depending on complexity

What Are Heat Pump Heat Strips?

Heat pump heat strips are electric resistance heating elements placed inside the indoor air handler or ductwork to produce heat by passing current through metal coils. They function like a conventional electric heater and are controlled by the heat pump’s thermostat or control board. Their role is to provide immediate, reliable heat when the heat pump’s compressor output is insufficient.

How Heat Strips Work With Heat Pumps

Heat strips engage when the heat pump cannot meet the set temperature or during specific operational modes. Typical triggers include very low outdoor temperatures, rapid call-for-heat scenarios, or during the defrost cycle when the outdoor unit temporarily reverses operation and does not provide heating.

Heat strips convert electrical energy directly into heat with nearly 100% conversion efficiency at the element level, but they are considered less efficient overall compared to the heat pump’s heat-moving process, which typically offers a Coefficient Of Performance (COP) greater than 1.

Types Of Heat Strips

Internal (Built-In) Heat Strips

Internal heat strips are installed inside the air handler or furnace cabinet. They are compact, integrated with the blower, and controlled by the unit’s control board. Internal strips provide fast warm air but increase load on the home’s electrical panel.

External (Auxiliary) Electric Heaters

External heat strips or auxiliary electric heaters mount in duct runs or dedicated enclosures. They serve similar functions but can be easier to replace or upgrade independently of the air handler.

Single-Stage Versus Staged Heat Strips

Staged heat strips allow multiple heating elements to activate sequentially (e.g., 5 kW then additional 5 kW) to match demand and reduce instantaneous electrical draw. Staged systems improve comfort and reduce peak electrical currents compared to single-stage, full-power activation.

When Do Heat Strips Activate?

Heat strips typically activate in these scenarios: during a call for supplemental heat when outdoor temperatures drop below the heat pump’s effective range, during rapid recovery after a setback thermostat change, and during defrost cycles when the heat pump temporarily runs in cooling mode to remove ice from outdoor coils.

Thermostats and control boards use temperature sensors, time delays, and stage logic to decide when to energize heat strips to avoid unnecessary energy use and short-cycling.

Energy Efficiency And Performance Considerations

Heat strips provide instant warmth but are less energy-efficient than a heat pump operating in heating mode. A heat pump can move multiple units of heat for each unit of electricity; heat strips provide one unit of heat per unit of electricity. Relying heavily on heat strips can raise utility bills significantly.

Best practice is to size and configure the heat pump so strip usage is minimized. Proper insulation, weatherization, and an appropriately sized heat pump reduce dependency on electric resistance heat.

Costs: Installation, Operation, And Lifetime

Installed cost varies with the type of heat strips, unit accessibility, and electrical upgrades required. Typical parts-only cost ranges from $200–$800. Labor can push installed prices to $300–$1,200 or more if panel upgrades or rewiring are needed to handle high amperage.

Operational cost depends on kW rating and electricity price. For example, a 5 kW strip at 240V draws about 20.8 amps and consumes 5 kWh per hour. At $0.20 per kWh, that costs $1 per hour. Continuous runtime during extended cold spells can quickly increase monthly bills.

Electrical Requirements And Safety

Heat strips require appropriate circuit breakers, wiring gauge, and often a two-pole disconnect near the unit. Many systems need a dedicated 240V circuit sized for full-strip load. Undersized wiring or improperly rated breakers create fire hazards and code violations.

When upgrading or installing heat strips, an electrical load calculation should be performed to confirm the service panel can handle the additional demand without exceeding safe capacity. Local code and NEC rules apply.

Control Strategies And Thermostat Integration

Advanced thermostats and control boards offer staged electric heat control, outdoor temperature sensors, and adaptive logic to minimize strip run time. Heat pump-specific thermostats can delay strip activation until the compressor has had a chance to meet demand, reducing reliance on resistance heat.

Using setback schedules responsibly is important: large setbacks can trigger prolonged strip use for recovery. Smaller temperature setbacks or smart thermostats with adaptive recovery optimize energy use.

Alternatives And Complementary Approaches

Homeowners can reduce strip dependence through better insulation, air sealing, and by selecting cold-climate heat pumps designed to maintain efficiency at low temperatures. Supplemental hydronic systems or mini-split electric heaters in critical zones can provide targeted warmth with less overall electricity than large strip banks.

Heat pump upgrades such as variable-speed compressors, multi-stage heat pumps, and improved refrigerants extend effective heating range and reduce strip activation frequency.

Maintenance And Troubleshooting

Routine maintenance includes visual inspection of the heater elements, checking connections for corrosion, and verifying control board functions. Faulty relays, burned-out elements, or tripped breakers are common issues when heat strips fail to operate.

Common indicators of a problem include cold air despite a strip call, breaker trips when strips energize, unusual odors when strips first run, or intermittent operation. Qualified HVAC technicians should service high-voltage components.

Practical Tips To Minimize Heat Strip Use

• Weatherize First: Insulate attics, seal gaps, and improve window performance to reduce heat load.
• Optimize Thermostat Settings: Use smaller setbacks and schedule gradual recovery to avoid long strip runtimes.
• Use Zoned Heating: Heat only occupied spaces with duct zoning or smart vents to lower overall demand.
• Invest In Cold-Climate Heat Pumps: Models rated for low outdoor temps decrease supplemental heat requirements.
• Implement Staged Heat: Prefer staged heat strips and control logic to lower peak electrical demand.

When Heat Strips Make Sense

Heat strips are practical when reliability and safety are priorities, such as in climates with occasional deep freezes, for emergency backup, or in homes where electrification is underway but full-system upgrades are planned for the future. They are also suitable for rapid warm-up needs, like when occupants return from extended absences.

For all-electric homes or properties without gas backup, heat strips provide a straightforward, code-compliant method to ensure indoor comfort in extreme conditions.

Regulatory And Incentive Landscape

Federal and state incentives increasingly encourage heat pump adoption, but incentives for heat strips themselves are uncommon because they increase electricity consumption. However, rebates for whole-system upgrades, heat pump replacements, and insulation projects can indirectly reduce strip usage and qualify homeowners for financial assistance.

Local utility programs sometimes offer rebates for smart thermostats, load control devices, or staged electric heat controls that can reduce peak demand and energy costs.

Decision Checklist For Homeowners

1. Assess Current System: Verify whether strips are internal or external and confirm amperage, voltage, and control compatibility.
2. Evaluate Home Envelope: Prioritize insulation, air sealing, and window upgrades to lower heating load.
3. Check Electrical Capacity: Ensure panel and wiring can safely support additional load or staged operation.
4. Compare Alternatives: Consider upgrading to a cold-climate heat pump or adding zoned heating before relying on strips.
5. Consult Professionals: Obtain quotes from licensed HVAC and electrical contractors and ask for load calculations and staged control recommendations.

FAQ: Common Questions About Heat Pump Heat Strips

Do Heat Strips Damage The Heat Pump?

Heat strips do not harm the heat pump when properly installed and controlled. They are designed as supplemental devices. Damage risk increases if wiring is incorrect, elements overheat, or controls are misconfigured.

How Long Do Heat Strips Last?

Typical lifespan ranges from 5 to 15 years depending on usage, maintenance, and operating environment. Frequent cycling and heavy load shorten element life.

Can A House Run Only On Heat Strips?

Technically yes, but it is usually cost-prohibitive. Running solely on electric resistance heat is significantly more expensive than heat pumps or gas furnaces for typical U.S. electricity prices.

Are Heat Strips Covered By Warranties?

Many manufacturers cover heat strips under parts warranties, but coverage terms vary. Installation-related damage or electrical faults may not be covered, so professional installation and documentation are recommended.

Resources And Further Reading

For reliable technical guidance, consult the manufacturer’s installation manuals, the National Electrical Code (NEC), and ENERGY STAR resources on heat pumps and home efficiency. Local utility programs provide rebates and technical assistance for heat pump upgrades and home weatherization.

For site-specific advice, homeowners should engage licensed HVAC contractors and certified electricians to perform load calculations and recommend the appropriate heat strip configuration and safety measures.

Key Takeaway: Heat pump heat strips are essential supplemental devices for reliable heating during extreme conditions, but homeowners should minimize their use through efficiency upgrades, proper controls, and system selection to keep energy costs and peak electrical loads under control.