Heat pump thermostat settings and setbacks
With a heat pump, keep setbacks small or use a thermostat with heat pump recovery logic, because a deep setback can make the system recover on backup heat.
Editorial staffEdited by heatpumpwiki
Contents
For heating with a heat pump, the main rule from DOE is: "Do not set back the heat pump's thermostat if it causes the backup heating to come on."Source 2 Small setbacks, or a thermostat that starts recovery early and limits backup heat, avoid that problem. In cooling mode, setbacks (setting the temperature up while you are away) do not have the same backup heat issue.
Why heat pumps and setbacks are different
With a furnace, turning the thermostat down overnight saves fuel, and the furnace can bring the house back up quickly. DOE's general guidance is that "you can save as much as 10% a year on heating and cooling by simply turning your thermostat back 7°-10°F for 8 hours a day from its normal setting."Source 1
Heat pumps recover more slowly. NRCan says: "Heat pumps have a slower response than furnace systems, so they have more difficulty responding to deep temperature setbacks."Source 3 When the house has to warm several degrees in the morning, the thermostat may call for backup heat to get there, and with electric resistance backup that heat costs more per unit than heat pump heat. NRCan explains that the backup "operates until the heat pump 'catches up,'" which "will reduce the savings that you might have expected."Source 3
DOE's older thermostat guidance went further: "Programmable thermostats are generally not recommended for heat pumps... when a heat pump is in its heating mode, setting back its thermostat can cause the unit to operate inefficiently, thereby canceling out any savings."Source 1 The same page notes that some thermostats designed for heat pumps "use special algorithms to minimize the use of backup electric resistance heat systems."Source 1 DOE's newer heat pump operation page recommends considering "a programmable thermostat with multistage functions suitable for a heat pump."Source 2 The two DOE pages differ in tone; both agree that setbacks should not bring on backup heat.
What the agencies recommend
| Source | Recommendation |
|---|---|
| NRCan | "Moderated setbacks of not more than 2°C should be employed or a 'smart' thermostat that switches the system on early, in anticipation of a recovery from setback, should be used."Source 3 |
| DOE | "Do not set back the heat pump's thermostat if it causes the backup heating to come on."Source 2 |
| DOE | "Maintaining a moderate setting is the most cost-effective practice."Source 1 |
A 2°C setback is about 3.6°F.
Thermostat features that help
- Early or adaptive recovery. The thermostat starts heating before the scheduled time so it can recover on the heat pump alone. Resideo's T6 Pro, for example, has "Adaptive Intelligent Recovery," in which "heating or cooling equipment will turn on earlier, ensuring the indoor temperature will match the setpoint at the scheduled time."Source 4
- Backup heat lockouts. An outdoor temperature limit above which backup heat cannot run. See Heat pump backup heat and lockout temperatures.
- Smart thermostats. ENERGY STAR says homes with high bills or that are often empty "can save approximately $100 a year with an ENERGY STAR certified smart thermostat."Source 5 Savings for a given house depend on how it is used and how the thermostat is configured for the heat pump.
Variable-speed systems
NRCan notes that "for variable speed systems, setbacks may allow the system to operate at a lower speed, reducing wear on the compressor and helping to increase system efficiency."Source 3
Fan setting
DOE recommends you "operate the system on the 'auto' fan setting."Source 2
Thermostat location
DOE says a thermostat "must be on an interior wall away from direct sunlight, drafts, doorways, skylights, and windows."Source 1 A thermostat in the wrong place can read a false temperature and cause unnecessary cycling. See Heat pump short cycling.
Ductless systems
Ductless indoor units usually have their own remote or wall controller per zone. The same principles apply: avoid large setbacks if the system has backup heat that would come on, and use the manufacturer's scheduling features within those limits.
A quick check
If your thermostat shows "aux" or "auxiliary heat" every morning after a scheduled setback ends, reduce the setback or turn on the thermostat's heat pump recovery feature. DOE's example of a correctly wired system: if it is 50°F outside and you raise the setpoint from 66°F to 70°F, "the strip heat should never activate."Source 6
Sources
- 1.Programmable Thermostats (archived copy of energy.gov/energysaver/programmable-thermostats, captured July 1, 2026). U.S. Department of Energy. Accessed Oct 25, 2026
- 2.Operating and Maintaining Your Heat Pump (archived copy of energy.gov/energysaver/operating-and-maintaining-your-heat-pump, captured May 29, 2026). U.S. Department of Energy. Accessed Oct 25, 2026
- 3.Heating and cooling with a heat pump. Natural Resources Canada. Accessed Oct 25, 2026
- 4.T6 Pro Programmable Thermostat Installation Instructions (33-00181EFS). Resideo. Accessed Oct 25, 2026
- 5.Heat & Cool Efficiently. ENERGY STAR (U.S. EPA and DOE). Accessed Oct 25, 2026
- 6.Air-Source Heat Pumps (archived copy of energy.gov/energysaver/air-source-heat-pumps, captured June 20, 2026). U.S. Department of Energy. Accessed Oct 25, 2026
More in Living with a heat pump
- Heat pump backup heat and lockout temperaturesAux heat supplements the heat pump automatically, emergency heat replaces it by hand, and outdoor lockout settings decide at what temperatures each one is allowed to run.
- Heat pump defrost cyclesIn cold, damp weather a heat pump periodically reverses for several minutes to melt frost off the outdoor coil, and steam, a whoosh and a stopped outdoor fan are normal parts of that.
- Heat pump filters and maintenanceCheck filters monthly and change or clean them at least every three months (ductless filters more often), keep the outdoor unit clear, and have a technician service the system once a year.
- Heat pump noiseOutdoor heat pump sound is rated in A-weighted decibels under AHRI Standard 270, variable-speed units are quieter at low speed and louder at full speed, and placement affects what you hear.