Controlling a heat pump with the wrong thermostat — or the right thermostat with the wrong settings — can erase thousands of dollars in efficiency gains. The most common mistake is using a conventional setback schedule (turning the temperature way down when you leave or sleep, then boosting it before you return) that works well for gas furnaces but actively hurts heat pump efficiency.
This guide explains the fundamental differences in how heat pumps should be thermostatically controlled, which thermostats are designed for heat pump operation, and how to configure yours for maximum savings and comfort.
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Use our free Heat Pump Savings Calculator →Why Heat Pump Thermostats Are Different
Gas furnaces and heat pumps have fundamentally different efficiency profiles relative to temperature recovery:
- Gas furnace: Delivers high-temperature air (120–140°F) and can rapidly recover from a setback — reheating a house by 5–8°F in 30–60 minutes. The short high-intensity reheating period uses fuel efficiently because furnaces operate at consistent AFUE regardless of how fast or slow they run.
- Heat pump: Delivers lower-temperature air (90–105°F) and takes longer to recover from setback. More critically — to recover quickly from a large temperature drop, the heat pump's backup electric resistance strips may activate. Electric resistance has a COP of 1.0 versus the heat pump's 2.0–4.0 COP. If resistance strips run for an extended period to make up a 6°F setback, the energy used can exceed what you saved by lowering the temperature.
Common mistake: Dropping the thermostat by more than 2–3°F when leaving or sleeping with a heat pump system that includes backup electric resistance heat. When you restore the set point, the system may activate resistance strips to recover faster, costing more energy than the setback saved.
The Correct Setback Strategy for Heat Pumps
The optimal approach depends on your heat pump type:
Variable-Speed (Inverter) Heat Pumps Without Resistance Backup
Modern variable-speed cold-climate heat pumps without significant backup resistance heating can use moderate setbacks similarly to gas furnaces. A well-designed variable-speed system can ramp up to handle a 5–7°F temperature recovery without efficiency penalties. If your system's backup resistance is minimal or set to activate only at very low outdoor temperatures, moderate setback (3–7°F) is appropriate and saves money.
Heat Pumps With Significant Electric Resistance Backup
For most conventional heat pump installations with electric resistance backup strips, the recommended setback strategy is:
- Limit setback to 2–3°F maximum during sleeping hours (e.g., 70°F → 68°F)
- During extended absence (8+ hours): A setback of 3–4°F may be appropriate, but configure the system to "pre-heat" gradually (not quickly) before your return to avoid triggering resistance strips
- Enable "smart recovery" or "adaptive recovery" if your thermostat offers this — it calculates when to start reheating so the home reaches set point at the scheduled time without using resistance heat
- Avoid large setbacks (5°F+) unless your system specifically has a lockout that prevents resistance strips from activating during recovery
Emergency Heat and Auxiliary Heat: Critical Settings
Auxiliary Heat (AUX Heat)
"Auxiliary heat" (AUX heat) refers to the backup electric resistance strips that supplement the heat pump when it can't meet demand. AUX heat activates automatically when:
- The thermostat setpoint is more than 2–3°F above the current temperature (recovery from setback)
- The outdoor temperature drops below the system's "lockout temperature" and the heat pump alone can't maintain setpoint
- The heat pump is in defrost cycle (AUX runs briefly to maintain indoor air temperature)
AUX heat activation should be occasional and brief. If you see "AUX" showing on your thermostat frequently during normal heating conditions above 25°F, your system may be undersized, the thermostat lockout temperature may be set too high, or a setback recovery is activating resistance heat unnecessarily.
Emergency Heat (EM Heat)
"Emergency heat" is a manual override mode that bypasses the heat pump entirely and runs only the electric resistance backup. Use this only when:
- Your heat pump outdoor unit has failed and you're waiting for repair
- Your service technician instructs you to use it
Do NOT run your heat pump in emergency heat mode during normal operation. Emergency heat consumes 2–4× more electricity than the heat pump for the same heating output.
Emergency Heat Warning: If your thermostat is in "EM Heat" mode accidentally, your electric bills will be dramatically higher. Check your thermostat display and ensure it shows "HEAT" not "EM HEAT" during normal winter operation.
The Best Smart Thermostats for Heat Pumps
Google Nest Learning Thermostat (4th Gen)
The Nest Learning Thermostat has dedicated heat pump support including AUX heat lockout settings, emergency heat management, and "sunblock" sensing. Its machine learning algorithm adapts to your schedule over time. The 2026 4th-generation model adds improved heat pump optimization and better low-temperature AUX heat lockout configuration.
- Heat pump support: Yes — including 2-stage heat pump configurations
- AUX lockout temperature: Configurable (prevent AUX activation above a set outdoor temp)
- Smart recovery: Yes — gradually reheats to avoid AUX activation
- Compatible with: Most central heat pump systems (check compatibility at nest.com)
- Price: ~$130–$180
Ecobee SmartThermostat Premium
The Ecobee is often considered the best thermostat specifically for heat pump systems. Its dedicated heat pump settings include configurable compressor lockout temperature, AUX heat lockout, and the ability to set different recovery strategies for heat pump vs. resistance modes. Room sensors allow more precise whole-home temperature management. Built-in Amazon Alexa.
- Heat pump support: Excellent — most comprehensive heat pump configuration options
- Compressor lockout: Configurable minimum outdoor temperature for compressor operation
- AUX heat differential: Configure how many degrees above setpoint triggers AUX
- Room sensors: Yes — average temperature across multiple rooms
- Price: ~$200–$250
Honeywell Home T10 Pro / T6 Pro
For homeowners wanting a more traditional thermostat experience with heat pump compatibility, Honeywell Home's T6 Pro and T10 Pro offer solid heat pump support including configurable AUX heat lockout and emergency heat settings. The T10 Pro adds smart sensor compatibility for multi-room monitoring.
- Heat pump support: Yes — 2-stage heat pump, AUX heat configuration
- Interface: Traditional button/dial interface, less smart-home integration
- Price: $80–$150
Manufacturer-Specific Thermostats
Some heat pump brands offer proprietary communicating thermostats that integrate more deeply with the system than any third-party thermostat:
- Mitsubishi Kumo Cloud / MAC-558IF-E: Full control of Mitsubishi mini-split systems via smartphone; zone-by-zone control; not compatible with standard thermostats
- Carrier Infinity Touch: Works with Carrier Infinity heat pumps; provides detailed operating data and sophisticated zoning
- Daikin ONE+: Works with Daikin systems for comprehensive monitoring and control
If you have a communicating (variable-speed) heat pump, using the manufacturer's compatible control system often unlocks additional efficiency features unavailable with third-party thermostats.
Recommended Heat Pump Thermostat Settings
| Setting | Recommended Value | Why |
|---|---|---|
| Heating setpoint | 68–72°F | Comfortable range; each degree lower saves ~1–3% |
| Night setback | 2–3°F maximum | Avoids triggering AUX heat during recovery |
| Away setback | 3–5°F (if away 8+ hours) | With smart recovery enabled |
| AUX heat lockout temp | Set at outdoor temp where gas becomes cheaper (if dual fuel) or 0–10°F for all-electric | Maximizes heat pump hours; minimizes expensive resistance heat |
| Compressor lockout temp | –10°F to –20°F for cold-climate units | Set per manufacturer specs |
| Recovery mode | Smart/gradual recovery | Avoids AUX heat spike during schedule recovery |
| Emergency heat | OFF (only enable for emergency) | EM heat costs 2–4× more per BTU |
The $60 Tax Credit for Smart Thermostats
The 25C Energy Efficient Home Improvement Credit provides up to $60 credit for ENERGY STAR certified smart thermostats as part of the $1,200 credit pool (separate from the $2,000 heat pump and $600 water heater credits). If you're already doing a heat pump installation and purchasing a qualifying smart thermostat, include it in your Form 5695 filing.
Mini-Split Control: App vs. Remote vs. Smart Thermostat
Mini-split heat pumps present different control options than central systems:
- Included wireless remote: Standard on all mini-splits. Easy to use but no scheduling without the app.
- Manufacturer app: Mitsubishi kumo cloud, Daikin mobile, LG ThinQ — allows scheduling, remote access, and integration with smart home platforms.
- Smart thermostat adapters: Devices like the Cielo Breez or Sensibo Sky install in front of the mini-split's IR sensor and translate smart thermostat commands to IR signals. Allows Google Home and Amazon Alexa control and scheduling.
- Native smart home integration: Some mini-split brands support direct Google Home or Amazon Alexa integration through Wi-Fi.
Pro tip: For multi-zone mini-split systems, the Cielo Breez Plus or similar adapters are an affordable way to add scheduling and smart home integration to any mini-split without buying the full manufacturer's ecosystem. At $50–$80 per unit, they can significantly improve your ability to manage energy costs across multiple zones.
Optimized thermostat settings and the right heat pump together maximize your annual savings.
Use our free Heat Pump Savings Calculator →