Best Smart Thermostat for a Heat Pump
For most heat pumps, buy the Google Nest Learning Thermostat (4th gen). Google publishes how it limits the costly backup heat, and at 5°F the typical certified cold-climate heat pump still makes 1.98 times the heat per kWh that the backup strips do.
Best for most heat pumps
Google Nest Learning Thermostat (4th gen)
$229.95 on Amazon
Check price on Amazon- Backup heat stays off above 40°F outside by default, and you can set it from 0 to 70°F (Google's settings guide).
- Runs 2 heat pump stages and 2 backup stages, and a dual-fuel furnace switch point (30°F by default).
- On the ENERGY STAR list (0.10 W standby), and on the Bonneville Power Administration (BPA) list of thermostats that control heat pump backup heat.
- Google's chart lists no C-wire requirement for it on a heat pump. Sold on Amazon by a third-party seller.
The thermostats ChatGPT recommends for a heat pump, checked
Asked for the best smart thermostat for a heat pump, ChatGPT names these four. For each: what its maker says it runs, its ENERGY STAR record, whether it is on BPA's heat-pump list, and whether Amazon could sell it today.
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ChatGPT: best for detailed control of the backup heat
ecobee Smart Thermostat Premium · ENERGY STAR listed · 1.83 W standby · on BPA's heat-pump list
ecobee says it runs 2 heat pump stages + 2 backup stages. Its spec page doesn't give a backup-heat lockout setting. ecobee's Essential is sold by Amazon, but it runs one heat pump stage and BPA's heat-pump list says ecobee 7, its model line, does not qualify.
- $229.95 on Amazon
ChatGPT: best for hands-off scheduling
Google Nest Learning Thermostat (4th gen) · ENERGY STAR listed · 0.10 W standby · on BPA's heat-pump list
Our pick (see above). Google says it runs 2 heat pump stages + 2 backup stages. Sold on Amazon by a third-party seller.
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$194 on AmazonChatGPT: best for value, if you skip the Premium's extras
ecobee Smart Thermostat Enhanced · ENERGY STAR listed · 1.51 W standby · on BPA's heat-pump list
ecobee says it runs 2 heat pump stages + 1 backup stage. Its spec page doesn't give a backup-heat lockout setting. Sold on Amazon by a third-party seller.
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ChatGPT: best for complex multi-stage and dual-fuel systems
Honeywell Home T10 Pro · ENERGY STAR listed · 1.65 W standby
Honeywell says it runs up to 3 heat / 2 cool. Its spec sheet states dual fuel, aux heat lockout and a wired outdoor sensor. BPA lists the T10 Pro, but names the builder model sold on Amazon (THX321WF2003W) as not qualifying.
Models from ChatGPT's answers to "What is the best smart thermostat for a heat pump?", asked October 24 and 25, 2026. Heat pump facts are each maker's own pages, linked in Sources.
Which one is right for your heat pump?
- $229.95 on Amazon
Heat pump with electric backup strips
Google Nest Learning Thermostat (4th gen) · Backup lockout 40°F default · 2 + 2 stages · ENERGY STAR listed
Set its backup heat lockout to 35°F or lower: Energy Trust of Oregon's rule. Google's default is 40°F.
- $229.95 on Amazon
Heat pump plus a gas furnace (dual fuel)
Google Nest Learning Thermostat (4th gen) · Dual-fuel switch point 30°F default · 2 furnace stages
You pick the outdoor temperature where the furnace takes over (30°F by default, 10 to 50°F). Google says to have a professional set up a dual-fuel system.
- See mini-split picks
Ductless mini-split
Check the mini-split maker first · Not on Google’s chart
Google's compatibility chart does not list ductless mini-splits, and ecobee says its thermostats work with most 24 V equipment.
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Communicating or proprietary system
Use the maker's own control · Two wires but heating and cooling
Google: “Proprietary systems aren’t compatible with Google Nest thermostats.” Its sign of one: only 2 wires, but you have both heating and cooling.
Prices are Amazon's on November 11, 2026. Every pick is on the ENERGY STAR list and BPA's heat-pump list.
01 / Backup heat
Backup heat: what it costs, and the setting that limits it
A heat pump moves heat in from outside. When it can't keep up, the thermostat turns on backup heat: usually electric strips in the air handler. Strips make 1 unit of heat per unit of power. At 5°F, the median certified cold-climate heat pump still makes 1.98 units of heat per unit of power (5,878 systems in the AHRI and ENERGY STAR records).12
At the U.S. average home price of 18.19¢ per kWh (EIA, year to date through July 2026), 100,000 Btu of heat costs about $5.33 from the strips and $2.69 from that heat pump at 5°F. Google puts it this way: “AUX heat can cost about 2 to 5 times as much as running your heat pump.”132 Compare at your rates.
The setting that controls this is the backup heat lockout: above that outdoor temperature, the strips stay off. Energy Trust of Oregon's rule: “The lockout temperature shall be set at or below 35°F.” Google ships the Nest at 40°F and lets you set 0 to 70°F, so lower it to 35°F or less unless the house can't stay warm.101
Backup heat (aux) comes on by itself when the heat pump can't keep up. Emergency heat is the strips alone, switched on by you, for when the heat pump is broken. Google: “Emergency Heat can be engaged from the thermostat or Home app.”1
02 / Wiring
The wires a heat pump thermostat needs
Count the wires at your old thermostat and read their letters before you buy. These are the ones that matter on a heat pump.
- O/B: the reversing valve.This wire switches the heat pump between heating and cooling. Some brands use O, some use B. Google: “Orientation can be O or B and activated seasonally or each cycle.” Set it to match your old thermostat, or the heat pump will cool when you ask for heat.1
- W2 or AUX: the backup heat.The strips. Google's Nest wiring table calls this terminal “Heat Relay (Stage 2) / Auxiliary Heat.” Honeywell's X8S page: “Auxiliary / emergency heat wire should go to AUX.”8
- Y1 and Y2: the compressor stages.A two-stage heat pump has both. The Nest Thermostat runs one stage; the Nest Learning (4th gen), ecobee Premium and Enhanced, and Honeywell X8S run two.3
- C: the power wire.Many “no C-wire needed” thermostats need one on a heat pump. The Nest Thermostat's listing says heat pump systems need “a C wire or other compatible power accessory”, and the Sensi Lite's says “Common wire(C-Wire) required for heat pump”. ecobee's Premium and Enhanced include an adapter; the Essential's is sold separately.15
03 / Dual fuel
Dual fuel: a heat pump with a gas furnace
Dual fuel means a heat pump outside and a gas or oil furnace inside. The thermostat should run the heat pump in mild weather and switch to the furnace below an outdoor temperature you pick.
On the Nest that point is the Dual Fuel Breakpoint: 30°F by default, settable from 10 to 50°F. Google's Heat Pump Balance feature does not apply to dual fuel, and Google says “If you have a dual fuel system, you will need to have a trained professional set up your thermostat.”13
ecobee says its thermostats work with “dual-fuel heat pumps”. Honeywell's T10 Pro sheet lists “Dual fuel and aux heat lockout” and a wired outdoor sensor, so it can read the real temperature at your house. Every Nest reads the outdoor temperature from local weather over Wi-Fi; Google: “Nest thermostats do not support an outdoor temperature sensor.”471
04 / The records
Is its ENERGY STAR record valid? And the stricter heat-pump list
Every thermostat ChatGPT recommends here is on the ENERGY STAR list today: we re-read the live list on October 25, 2026 and found each model's record, with the same standby watts and accuracy as the copy our smart thermostat page uses. ENERGY STAR certifies the whole thermostat; it does not test heat pump settings.11
For that, the Bonneville Power Administration keeps a separate list for utility rebates in the Northwest. To be on it, a thermostat needs “Heat pump auxiliary heat control and optimization capabilities”. 5 of the 7 thermostats in our table are on its August 3, 2026 list. Two caveats from the list itself: “ecobee3 Lite and ecobee 7 do not qualify” (ecobee 7 is the Essential), and the T10 Pro builder model sold on Amazon (THX321WF2003W) is named as not qualifying.9
05 / Side by side
Heat pump controls, maker by maker
| Thermostat | Stages | Backup lockout | Dual fuel | C-wire | ENERGY STAR | BPA list | Price | Buy |
|---|---|---|---|---|---|---|---|---|
| Google Nest Learning Thermostat (4th gen) | 2 + 2 backup | Yes: 40°F by default, 0 to 70°F | Yes: switch point 30°F by default, 10 to 50°F | None listed in Google's chart | 0.10 W | Yes | $229.95 | Buy |
 Google Nest Thermostat | 1 + backup | Yes: 40°F by default, 0 to 70°F | Single-stage furnace only | Required on a heat pump (or Google's adapter) | 0.10 W | Yes | $104 | See Sensi on Amazon |
| ecobee Smart Thermostat Premium | 2 + 2 backup | Not on its spec page | Yes | Adapter in the box | 1.83 W | Yes | — | |
| ecobee Smart Thermostat Enhanced | 2 + 1 backup | Not on its spec page | Yes | Adapter in the box | 1.51 W | Yes | $194 | Buy |
 ecobee Smart Thermostat Essential | 1 + 1 backup | Not on its spec page | Yes | Adapter sold separately | 0.88 W | No | — | |
| Honeywell Home T10 Pro | Up to 3 heat / 2 cool | Yes | Yes | Not on its spec page | 1.65 W | No | — | |
 Honeywell Home X8Ssold by Amazon | Up to 3 heat / 2 cool | Not on its spec page | Not on its spec page | Required (free adapter by mail) | 2.59 W | Yes | $259.99 | Buy |
Every thermostat here has an O/B terminal for the reversing valve. Stages, lockout, dual fuel and C-wire are each maker's own page or sheet (linked in Sources). ENERGY STAR: the certified standby watts on its record. Stages: heat pump stages + backup heat stages. C-wire: what it needs on a heat pump. BPA: on the August 3, 2026 list. Prices read live November 11, 2026.
06 / Questions
Frequently asked
- What temperature should I set the aux heat lockout to?
- Energy Trust of Oregon says at or below 35°F. Above that outdoor temperature, the backup strips stay off and the heat pump does the work. Google's Nest default is 40°F. If your house can't stay warm on the coldest days, raise it a few degrees.
- What is the difference between aux heat and emergency heat?
- Aux heat is backup heat the thermostat turns on by itself when the heat pump can't keep up. Emergency heat is the same strips, turned on by you, with the heat pump off. Use emergency heat only when the heat pump is broken: it is the most costly way to heat.
- Do I need a C-wire for a smart thermostat on a heat pump?
- Often, yes. The Nest Thermostat's listing and the Sensi Lite's both say a heat pump needs one. Google's chart lists no such need for the Nest Learning (4th gen). ecobee's Premium and Enhanced come with an adapter that makes one.
- What is the O/B wire?
- It runs the reversing valve that switches a heat pump between heating and cooling. Some brands use an O wire and some a B wire. Set the new thermostat to the same letter as the old one.
- Does the Nest Learning Thermostat work with dual fuel?
- Yes. Google's chart lists it for a heat pump with a one- or two-stage furnace. You set a Dual Fuel Breakpoint (30°F by default). Heat Pump Balance does not apply to dual fuel, and Google says a professional should set up a dual-fuel system.
- Is the ecobee Essential good for a heat pump?
- It runs one heat pump stage and one backup stage, and ecobee says it works with dual-fuel heat pumps. But BPA's list of thermostats with heat pump backup-heat control says ecobee 7, the Essential's model line, does not qualify. The Premium and Enhanced do.
- Will a smart thermostat work with my ductless mini-split?
- Usually not the way a wall thermostat runs a ducted system. Google's chart doesn't list mini-splits, and ecobee's thermostats are for 24 V equipment. Check the mini-split maker's own controls first.
- How do I know if my thermostat model is ENERGY STAR certified?
- Look up its model number on the ENERGY STAR certified smart thermostat list. Each one ChatGPT recommends for a heat pump is on it today. For heat pump backup control, BPA's qualified list is the stricter check.
References
Sources
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ChatGPT answers to "What is the best smart thermostat for a heat pump?" (3 runs, October 24 and 25, 2026)
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Amazon listings: price, seller and C-wire wording