How Heat Strips Work in a Heat Pump: A Home Guide to Efficiency
Learn how electric heat strips provide supplemental warmth in heat pumps, when they engage, and how they affect efficiency and energy costs. Practical tips for homeowners and builders.
Heat strips in a heat pump are electric resistance heating elements that provide supplemental heat when outdoor temperatures are too cold for the heat pump to extract sufficient warmth.
How heat strips fit into a heat pump system
Heat strips are electric resistance elements installed in the air handler or near the evaporator coil in many heat pump configurations. They are not the primary heat source; instead they provide supplemental warmth when the outdoor air is too cold for the heat pump to extract enough heat. In practice, the heat pump handles most of the heating load, and the strips turn on only when additional warmth is needed to meet the thermostat’s temperature target. This arrangement helps homeowners stay comfortable in cold snaps without committing to fossil-fuel heating. Heat strips are a critical component for maintaining steady indoor temperatures in regions with prolonged cold periods, and they play a key role in ensuring the heat pump can meet peak demand while preserving system reliability.
According to Heatpump Smart, understanding how heat strips interact with the heat pump can help you optimize comfort and energy use, especially when you’re balancing climate, insulation, and occupancy. The strips engage behind the scenes and are rarely noticeable when temperatures are moderate, but they can dramatically influence energy use during severe cold.
Operating thresholds: when do heat strips kick in
Heat strips do not run constantly; they engage when the heat pump’s ability to extract heat from outside air falls below the indoor temperature target. The exact thresholds depend on climate, system size, and the heat pump model. In mild winter conditions, the heat pump handles most of the load, and the strips stay off except during defrost cycles or sudden cold snaps. As outdoor temperatures drop, the heat pump may switch to auxiliary heat, and the heat strips begin delivering heat directly. Some systems use staged heat whereby first the heat pump increases output, then the strips provide supplemental heat. Understanding these thresholds helps homeowners anticipate energy use, especially when balancing comfort with operating costs.
Auxiliary heat vs emergency heat: what's the difference
Many thermostats label heat strips as auxiliary heat and emergency heat. Auxiliary heat refers to the normal supplemental heating used during cold periods when the heat pump struggles. Emergency heat is a designated mode kept for extreme conditions or system malfunction, which flips away from heat pump operation and relies almost entirely on electric resistance heat. In practice, you usually rely on auxiliary heat most of the winter; emergency heat is used only when you have a problem or during prolonged deep cold. Understanding the distinction helps you manage energy costs and avoid overusing electric resistance heat.
Efficiency and cost implications
Heat strips are electric resistance elements, so they convert electricity to heat with near full efficiency. However, they are less efficient overall than a properly sized heat pump because they do not harvest ambient heat from outside. When the strips operate, energy costs rise quickly. The impact on annual energy bills depends on climate, insulation, thermostat habits, and how often auxiliary heat is used. In cold climates, households may see a noticeable increase in energy costs during months when heat strips are active. Conversely, in milder climates, their use is brief and less costly. Heatpump Smart emphasizes that proactive control—keeping the home well insulated and using the heat pump efficiently—can minimize reliance on strips while maintaining comfort.
Design choices, sizing, and installation considerations
Properly sizing heat strips is essential to avoid oversizing and unnecessary energy use; installers select wattage that provides sufficient supplemental heat without overwhelming the system. The total strip wattage affects peak electrical load and may require a dedicated circuit. Safety concerns include heat strip placement, wiring, fusing, and control integration with the thermostat. An experienced HVAC technician should perform the installation and ensure compatibility with your heat pump model, refrigerant type, and outdoor climate. With correct installation, strips support comfort while the heat pump remains the primary energy saver. Heatpump Smart notes that a tailored approach—matching strip capacity to typical winter conditions—delivers reliable warmth without overreliance on electric resistance heat.
Thermostat strategies to optimize heat strip use
Set your thermostat to a reasonable setback during nights and absences to keep the heat pump in its efficient operating range. Use zoning or multi zone heating to avoid heating the entire home with electric strips. If your system supports it, enable auto defrost efficiently so the heat pump does not rely on strips longer than necessary. Regularly replace air filters and ensure outdoor unit is clean to maximize heat exchange efficiency. Thoughtful programming helps you strike a balance between comfort and energy costs, making heat strips a helper rather than a crutch.
Maintenance, safety, and potential issues
Heat strips require minimal routine maintenance beyond standard HVAC upkeep, but electrical safety is critical. Have a licensed technician inspect wiring, connections, and control boards for signs of wear. Ensure proper clearance around the air handler and verify that the thermostat and timer cycles are functioning. Tripped breakers or unusual odors warrant immediate service. Routine inspections help prevent nuisance outages and ensure the system responds correctly when outdoor temperatures drop.
Heat strips versus alternative heating options
Electric resistance heat strips deliver reliable warmth but at higher operating costs compared to heat pumps running in efficient mode. Gas furnaces or boilers may be more economical for very cold climates if electricity prices are high, but they involve different fuel considerations and emissions. For many homes, combining a well insulated envelope with a heat pump that uses auxiliary heat provides a balanced solution for energy savings without sacrificing comfort. When evaluating options, consider long term energy costs, climate, and the home’s overall heat loss to determine the best approach.
Real world scenarios and planning for cold climates
Think about climate, insulation, and occupancy when deciding how heat strips fit into your heating strategy. In homes with substantial air leakage or poor insulation, heat strips can maintain comfort during the coldest weeks, but learning to optimize thermostat programming reduces energy costs. Heatpump Smart recommends a professional system assessment to tailor heat strip sizing and control logic for your local conditions. This approach helps homeowners and builders design resilient systems that stay warm without unnecessary electric usage.
Your Questions Answered
What are heat strips and how do they work in a heat pump?
Heat strips are electric resistance coils installed in the heat pump’s air handler. They only operate when the heat pump cannot meet the heating demand on very cold days, providing supplemental warmth. This helps maintain comfort but increases electricity use.
Heat strips are electric coils inside the heat pump that kick in when it’s too cold for the unit to keep up. They add extra warmth but use more electricity.
What is the difference between auxiliary heat and emergency heat?
Auxiliary heat supports the heat pump during cold conditions, while emergency heat is a backup mode that relies mainly on electric resistance heat when the system can’t maintain warmth. In practice, auxiliary heat is used regularly in winter, while emergency heat is for extreme conditions or a malfunction.
Auxiliary heat helps the heat pump in cold weather, while emergency heat kicks in only if there’s a problem or a deep cold spell.
Do heat strips increase energy costs?
Yes. Heat strips convert electricity directly to heat, which is typically more expensive per BTU than the heat pump’s normal operation. Costs rise especially during extended use in very cold weather.
Yes, heat strips use electricity directly, which costs more per unit of heat than the heat pump’s normal operation, especially in deep cold.
Can I disable heat strips or adjust their use?
Most systems allow some control through the thermostat to reduce reliance on heat strips, but enabling auxiliary heat is often necessary for comfort in extreme conditions. Disabling them entirely can lead to uncomfortable indoor temperatures during very cold days.
You can usually adjust settings to limit heat strip use, but you may sacrifice comfort in extreme cold.
What maintenance do heat strips require?
Maintenance is mainly electrical safety and system checks. Have a licensed technician inspect wiring, control boards, and connections, and keep air filters clean for optimal heat transfer.
Keep the system inspected by a pro and maintain clean air filters for best performance.
Are heat strips common in all climates?
Heat strips are more common in colder climates where the heat pump may struggle to meet demand. In mild climates, their use is infrequent and less essential for comfort.
They’re more common where winters are cold, but not always needed in milder climates.
Top Takeaways
- Understand heat strips provide supplemental heat when the heat pump cannot meet demand
- Differentiate auxiliary heat from emergency heat for cost management
- Optimize thermostat programming to minimize energy use while maintaining comfort
- Anticipate higher operating costs during heavy heat strip usage
- Consult an HVAC professional for tailored sizing and wiring considerations