Understanding how heat strips work with heat pumps is essential for homeowners seeking energy-efficient comfort. Many are unaware of the vital role heat strips play, especially during colder months. This guide explores what a heat strip is, how it functions in a heat pump system, why it matters, and considerations for installation and operation.
Heat Strips And Heat Pumps: Key Facts At A Glance
| Feature | Details |
|---|---|
| Purpose | Provides supplemental heat when a heat pump struggles in very cold weather |
| Type | Electric resistance heating element, often installed in the air handler |
| Activation | Automatically during defrost cycle or when indoor temp drops below set point |
| Efficiency | Less efficient than heat pump heating, higher energy consumption |
| Ideal Usage | Backup for heat pump in freezing temperatures or rapid heating needs |
What Is A Heat Strip And How Does It Work?
A heat strip is essentially an electric heating element, similar to the coils found in traditional electric furnaces. In heat pump systems, these strips are installed in the air handler and serve as a backup or auxiliary heat source. When the outdoor temperature drops and the heat pump can’t meet the heating demand efficiently, the heat strip activates to help maintain indoor comfort.
Heat strips use electric resistance to generate heat, warming the air as it passes over the coils. This heated air is then distributed throughout the home via the heat pump’s ductwork. While highly effective at adding warmth, this process is energy intensive compared to the normal operation of a heat pump.
Why Do Heat Pumps Need Heat Strips?
Heat pumps are incredibly efficient in moderate climates because they move heat rather than generate it. However, as outdoor temperatures approach freezing, their ability to extract heat diminishes. To overcome this, heat strips act as a supplemental heat source. In very cold weather, or if the system goes into defrost mode, the heat strip ensures the home remains comfortable.
- Colder Climates: Heat strips are essential for homes in regions that experience sub-freezing temperatures.
- Rapid Recovery: They help warm a home quickly after setbacks or during sudden temperature drops.
- System Defrost: During defrost cycles, the heat strip maintains warm airflow even when the heat pump temporarily reverses to melt outdoor ice.
Where Are Heat Strips Installed In A Heat Pump System?
Heat strips are most commonly installed in the air handler—the indoor component of a heat pump system. The air handler includes a blower to circulate air and may already contain slots or mounting points for heat strips. In some hybrid or dual-fuel heat pump system designs, an electric or gas furnace may act as the auxiliary heat source instead of a heat strip.
The installation is typically straightforward for professionals, but it must be sized and configured to match the capacity and wiring of the system for optimal performance.
How Do Heat Strips Activate And Operate?
Automatic Activation
Modern thermostats and heat pump controls automatically manage when heat strips turn on. When the heat pump alone cannot maintain the thermostat’s set temperature—usually due to cold outdoor air—an auxiliary heat signal triggers the heat strip. Likewise, in defrost mode, the heat strip supplies warmth as needed.
Manual Override
Some thermostats offer a “emergency heat” or “auxiliary heat” setting, allowing users to manually activate the heat strips. This can be useful if the heat pump is not functioning correctly or is undergoing repairs, ensuring continued indoor heat.
Are Heat Strips Efficient?
While **heat pumps are highly energy-efficient** in normal operation, heat strips are not. Electric resistance heating (the type used by heat strips) converts nearly all input electricity into heat—but at a substantial energy cost. Whereas heat pumps can deliver 2-4 units of heat for every unit of electricity, heat strips deliver only one unit of heat per unit of electricity.
Heat strips are best used as a backup rather than a primary heat source to keep electricity bills manageable. System controls are designed to minimize heat strip usage by prioritizing heat pump operation whenever possible.
Identifying The Signs Your Heat Strips Are Running
It isn’t always obvious when the heat strips are active. Here are common indicators:
- Thermostat displays “auxiliary” or “emergency heat” mode
- Electric bills are significantly higher during cold snaps
- Warm air feels hotter and dryer than usual from vents
- Indoor warmth persists even when the outdoor unit is iced or off
Many smart thermostats will also show a status indicator or usage report when auxiliary heat is in use.
Sizing And Selecting The Right Heat Strip
Proper sizing of a heat strip is crucial for system efficiency and comfort. Heat strips are available in a range of sizes (measured in kilowatts, kW). The right size depends on:
- Home square footage and insulation quality
- Sizing and capacity of the heat pump system
- Climate zone and expected minimum outdoor temperatures
- Electrical service capabilities in your home
| Home Size (sq ft) | Recommended Heat Strip Size (kW) |
|---|---|
| Up to 1,000 | 5 kW |
| 1,000 – 1,500 | 7.5 kW |
| 1,500 – 2,000 | 10 kW |
| 2,000 – 2,500 | 15 kW |
Consult a licensed HVAC contractor for personalized sizing and installation.
Heat Strip Cost And Energy Consumption
Operating a heat strip increases energy costs due to higher electricity consumption. On average, running a 10kW heat strip costs about $1.00 to $1.50 per hour, depending on your local utility rates. Over the course of a cold spell, this can add significantly to your monthly bill—especially if the system relies on heat strips for many hours each day.
- Use programmable thermostats and efficient settings to minimize auxiliary heat reliance.
- Consider system upgrades or insulation improvements to reduce overall heating demand.
Maintenance And Lifespan Of Heat Strips
Heat strips generally require minimal maintenance but should be checked regularly as part of your annual HVAC inspection. Inspect for:
- Electrical connections and wiring integrity
- Signs of overheating, corrosion, or burn marks
- Proper cycling and operation as verified by a technician
With routine care, most heat strips can last 10-15 years or more, aligning with the lifespan of quality heat pump systems.
Heat Strip Vs. Emergency/Backup Heat: What’s The Difference?
Heat strip, auxiliary heat, and emergency heat are related but distinct terms:
- Heat Strip: The actual electric resistance element installed in the air handler.
- Auxiliary Heat: Supplemental heat automatically activated by the system when needed.
- Emergency Heat: Manually switched mode to use the heat strip exclusively (bypassing the heat pump), used in system failure or extremely cold weather.
The heat strip always serves as the physical source of backup heat, while auxiliary and emergency heat refer to how and when it’s used.
Benefits And Drawbacks Of Heat Strips In Heat Pumps
Benefits
- Reliable supplemental heat in sub-freezing conditions
- Keeps home comfortable during heat pump defrost or compressor failure
- Easy to integrate with most air handling units
Drawbacks
- Inefficient compared to heat pump operation, leading to higher energy bills
- Not suitable as a primary heat source for extended periods
- May require higher capacity electrical circuits
Heat Strips In Various Climate Zones
Heat strip significance varies based on climate:
- Southern & Coastal States: Heat strips are rarely needed, except during occasional extreme cold snaps.
- Mid-Atlantic & Midwest: Heat strips routinely provide backup heat several times each winter.
- Northern States & Mountains: More robust backup or dual-fuel options may be preferable, as heat strips may run frequently and consume significant energy.
Smart Controls And Reducing Heat Strip Usage
Modern HVAC systems use sophisticated controls to minimize reliance on heat strips. Features include:
- Variable speed compressors for better low-temp performance
- Intelligent thermostat algorithms that delay or stage heat strip activation
- Remote monitoring and control via smartphone apps
Homeowners are encouraged to optimize settings, use scheduling, and upgrade insulation to maximize comfort while reducing costs.
Installation Requirements And Safety Considerations
Professional installation is critical for heat strips. Key requirements include:
- Proper sizing and matching to the air handler and electrical infrastructure
- Secure mounting and safe electrical connections
- Adherence to local building codes and manufacturer instructions
- Inclusion of overcurrent protection devices
Never attempt DIY installation of heat strips, as improper wiring poses serious fire and shock risks.
Troubleshooting Common Heat Strip Issues
While heat strips are simple devices, issues can arise. Common problems include:
- Heat strip fails to activate when needed—could indicate a thermostat or relay issue
- Persistent auxiliary heat mode—even in mild weather—suggests a heat pump malfunction
- Tripped breakers or burnt wiring—indicate electrical overload or connection failures
Prompt service by qualified technicians is recommended for any suspected heat strip problems.
Alternative Supplemental Heating Options
For areas with frequent cold spells, alternatives to standard heat strips may be more cost-effective:
- Dual-fuel systems pairing heat pumps with high-efficiency gas furnaces
- Ductless mini-split systems with low ambient temperature ratings
- Geothermal heat pumps for even higher winter performance
Each option has advantages and may reduce total electricity consumption over time.
Frequently Asked Questions About Heat Strips For Heat Pumps
- Are heat strips required in every heat pump system?
Not in all climates, but highly recommended where winter temperatures drop near or below freezing. - Can I upgrade or replace my heat strip module?
Yes—HVAC technicians can upgrade or change out heat strips, usually when the air handler is serviced. - Is it dangerous if the heat strip runs too long?
Prolonged operation may overheat wiring or cause excessive energy use; it’s best to have the system checked if the heat strips seem always on. - How do I lower heat strip usage?
Improve home insulation, seal drafts, use programmable thermostats, and keep the heat pump well maintained.
Summary: Key Takeaways On Heat Strips For Heat Pumps
- Heat strips are essential backups in many heat pump systems, especially where winter temperatures routinely fall below freezing.
- They ensure comfort during cold, rapid recovery needs, and defrost cycles, but at higher operating costs.
- Smart controls and proper system sizing help limit heat strip use to only what is truly needed.
- Consult with licensed HVAC professionals for selection, installation, and maintenance to ensure safety and efficiency.