The ecobee Smart Thermostat Premium is the best smart thermostat for heat pump systems when you want direct control over when backup heat may run. ecobee lists it for heat pumps with up to two compressor stages plus two auxiliary-heat stages, includes dual-fuel systems among its supported types, and exposes separate outdoor-temperature thresholds for the compressor and for aux heat. Those three capabilities are where the published heat-pump specifications of these four thermostats differ most.
Choose the Google Nest Learning Thermostat (4th gen) if you would rather let the thermostat decide when aux heat helps, through Google’s Heat Pump Balance, and your backup heat is not a furnace. Choose the Sensi Touch 2 Smart Thermostat ST76 when you want to set an aux lockout and a balance point by hand and already have a C wire. Choose the Amazon Smart Thermostat only for a simpler heat pump with no gas or oil furnace behind it.
| Thermostat | Best for | Deciding facts | Main compromise |
|---|---|---|---|
| ecobee Smart Thermostat Premium | Adjustable aux-heat control | Heat pumps with up to 2 compressor and 2 aux stages; dual fuel listed; compressor and aux outdoor thresholds; SmartSensor included | More settings to get right; the similar Smart Thermostat Enhanced allows only 1 aux stage |
| Google Nest Learning Thermostat (4th gen) | Automatic aux decisions | Up to 2 heat-pump and 2 alternate heating stages, 2 cooling stages; O/B, AUX, AUX2 and E terminals; Heat Pump Balance; Matter | Heat Pump Balance is unavailable on dual-fuel systems |
| Sensi Touch 2 Smart Thermostat ST76 | Manual lockout and balance point | Heat-pump setups up to 4H/2C; aux lockout and balance point from internet weather or an outdoor sensor; Sensi room-sensor support | C wire required; dual fuel must be confirmed for this model |
| Amazon Smart Thermostat | Simple heat pumps in Alexa homes | Emergency Heat mode for heat pumps; C wire or Amazon’s adapter bundle | No dual-fuel support; no outdoor aux lockout documented in this research |
Capabilities in the table come from the makers’ published documentation; confirm each one in that maker’s compatibility checker for your exact equipment.
If your equipment requirements also permit the middle ecobee model, the Smart Thermostat Enhanced review compares the installed package and separately purchased room sensors. Confirm stage and accessory support first; a lower hardware price does not compensate for a lost HVAC function.
Which smart thermostat is best for a heat pump?
The best smart thermostat for a heat pump is the one whose maker confirms your exact stages and backup heat, then lets you control when that backup runs. Among these four, the ecobee Premium offers the most adjustable version of that control. Nest automates it, the Sensi Touch 2 exposes it as two manual settings, and Amazon’s model suits simple systems without a furnace.
The order changes with the equipment. On published specifications, all four can serve a single-stage heat pump with electric strip heat; a second aux stage narrows the field, and dual fuel reshuffles it.
Heat-pump fit sheet: seven items to confirm before ordering
A replacement thermostat has to reproduce every function your current heat-pump control performs. Each maker’s checker asks which terminal labels are in use on your existing thermostat. If reading them means removing the thermostat cover, follow the checker’s own power-off guidance or ask an HVAC technician to collect them. This sheet is a pre-purchase record, not wiring instructions.
| # | Confirm | How it usually appears | Why it changes the pick | Maker-published position (confirm in each checker) |
|---|---|---|---|---|
| 1 | Reversing valve | A wire on an O, B or O/B terminal | The thermostat drives the valve that switches the heat pump between heating and cooling | Nest’s spec sheet and ecobee’s heat-pump documentation reference O/B; confirm Sensi and Amazon for your system |
| 2 | Compressor stages | Y1 alone, or Y1 and Y2 | A two-stage compressor needs both stages controlled | ecobee Premium: up to 2; Nest: up to 2 heat-pump heating stages; Sensi Touch 2: within its 4H/2C limit; Amazon: confirm |
| 3 | Aux heat stages | W1, W2, AUX or AUX2 | A second aux stage rules out some models | ecobee Premium: 2 (Enhanced: 1); Nest: up to 2 alternate stages; Sensi: within 4H/2C; Amazon: aux supported, confirm the count |
| 4 | Emergency heat | An E terminal or an Em Heat mode | A manual backup mode, separate from automatic aux heat | Nest lists E; Amazon documents an Emergency Heat mode; confirm ecobee and Sensi behavior |
| 5 | Furnace backup (dual fuel) | Heat pump plus a gas or oil furnace | The thermostat must manage the handoff between two heat sources | Amazon: not compatible; Nest: compatible, without Heat Pump Balance; ecobee: dual fuel listed; Sensi Touch 2: confirm |
| 6 | Outdoor-temperature rules | Aux lockout, compressor lockout or balance point | Decides when strip heat or the furnace may run | ecobee: adjustable thresholds; Nest: automatic Heat Pump Balance, manual lockout on dual fuel; Sensi: aux lockout and balance point; Amazon: none found in this research |
| 7 | Thermostat power | A C (common) wire | Without one, some models need an adapter or will not run | ecobee: ask its checker which power option applies; Nest: Google says most homes don’t need a C wire; Sensi Touch 2: C wire required; Amazon: C wire or its adapter |
A worked inventory
Suppose your current thermostat uses R, C, G, Y1, Y2, O/B, W1 and W2, and the installer’s paperwork says W1 and W2 are electric strip heat. These labels are an illustrative scenario, not a wiring diagram. Count them against the sheet:
- Y1 + Y2 = 2 compressor stages
- W1 + W2 = 2 aux-heat stages
- No furnace = not dual fuel
On published specifications, the ecobee Premium and the Nest (4th gen) both cover two compressor stages with two aux stages. The ecobee Smart Thermostat Enhanced does not, because ecobee limits it to one aux stage on a heat pump.
Now change one fact: the backup heat is a gas furnace. The Amazon Smart Thermostat drops out entirely, and Nest still supports the system but replaces Heat Pump Balance with a lockout temperature you set yourself. One equipment fact moved two of the four picks.
Save each checker’s result with your order confirmation. If a checker and a retail listing disagree, the checker wins.
1. ecobee Smart Thermostat Premium: most control over aux heat
Identity check. Buy the Premium, not the Smart Thermostat Enhanced, if your heat pump has two stages of auxiliary heat. ecobee lists the Premium for heat pumps with two compressor stages and two aux stages; the Enhanced stops at one aux stage on a heat pump. The two look alike in search results, so match the full product name on the listing.
Why it wins for this buyer. ecobee’s threshold settings include a Compressor Min Outdoor Temp, below which the heat pump stops and backup heat takes over, and an Aux Heat Max Outdoor Temp, above which aux heat stays off. Those two values give an installer or an informed owner a direct lever over when resistance strip heat or furnace fuel is allowed to run. ecobee also lists dual-fuel heat pumps among its compatible system types, and the Premium includes a SmartSensor for a room-temperature reference away from the thermostat’s own wall.
The real compromise. Adjustable means someone has to choose the values. ecobee’s own threshold guidance points owners to the heat pump manufacturer for the compressor’s minimum operating temperature, so don’t copy a number from a forum post.
Buy it if you have two aux stages or a furnace backup and want explicit outdoor-temperature control. Skip it if you want the thermostat to work out aux timing on its own, or nobody in the household will revisit the settings after the first cold snap.
Strongest alternative: the Nest (4th gen), if you prefer automation to settings on a non-dual-fuel system.
2. Google Nest Learning Thermostat (4th gen): automatic heat-pump balance
Identity check. This is the fourth-generation Learning Thermostat introduced in 2024, sold with a Nest Temperature Sensor (2nd gen) in Polished Silver, Polished Obsidian and Polished Gold finishes. Google sells other Nest thermostats; do not apply these heat-pump specifications to an earlier generation or to the non-learning Nest Thermostat.
Why it wins for this buyer. Google’s specifications list control of up to two stages of heat-pump heating plus two stages of alternate heating, up to two cooling stages, and the O/B, AUX, AUX2 and E terminals heat pumps commonly use. For a heat pump with aux heat, Google’s help pages describe Heat Pump Balance setting the lockout or breakpoint for you, so there is no outdoor temperature to pick. It also supports Matter, so basic control isn’t confined to one app for households on Apple Home, SmartThings or Alexa.
The real compromise. Google says Heat Pump Balance does not apply to dual-fuel systems; there you set a lockout temperature manually in the thermostat’s equipment settings. You also trade transparency for convenience: you trust Google’s logic instead of setting thresholds yourself.
Power. Google says most homes don’t need a C wire for this model. “Most” is not a result for your house; its checker makes that call.
Buy it if your heat pump has electric aux heat, you want hands-off aux decisions, and a learning schedule appeals to you. Skip it if your backup is a furnace and automatic balancing was the reason to buy, or you want to see and set every threshold.
3. Sensi Touch 2 Smart Thermostat ST76: manual lockout and balance point
Identity check. The Touch 2 is model ST76; the earlier Sensi Touch is ST75. Sensi’s model comparison says only the ST76 supports Sensi room sensors and lists a C wire as required for both. Some listings still carry the older Emerson name alongside Sensi, so match “Touch 2” and “ST76” rather than the brand line.
Why it wins for this buyer. Sensi documents two heat-pump settings driven by outdoor temperature. An aux lockout keeps backup heat off above a temperature you choose, and a balance point locks out the heat pump below a temperature you choose. The outdoor reading can come from internet weather data or from an outdoor sensor. Sensi’s heat-pump configurations for the Touch 2 run up to 4H/2C. It is the most direct way on this list to set both rules by hand.
The real compromise. The C-wire requirement rules it out for homes without one unless an HVAC technician provides thermostat power. Sensi’s sell sheet for the earlier Touch (ST75) describes dual-fuel control, but confirm that the Touch 2 handles your dual-fuel configuration in Sensi’s compatibility tools before relying on it. Sensi notes that aux heat settings exist only on some of its models, so buy for this exact model, not the brand.
Buy it if you have a C wire, a heat pump with backup heat, and installer guidance on when backup heat should be locked out. Skip it if there’s no C wire, or you want the thermostat to choose those temperatures for you.
4. Amazon Smart Thermostat: simplest pick for Alexa heat-pump homes
Identity check. Amazon sells it alone and bundled with a C-wire adapter; pick the bundle when your system has no C wire and Amazon’s checker approves the adapter.
Why it fits this buyer. Amazon’s help pages cover an Emergency Heat mode for heat-pump systems, and its compatibility guidance includes heat pumps with auxiliary heat. For an uncomplicated heat pump in a home that already runs on Alexa, it covers schedules, remote adjustment and voice control through the Alexa app.
The real compromise. Amazon states that it does not work with heat pumps backed up by a gas or oil furnace. This research also found no documented outdoor-temperature aux lockout for it; treat that as unconfirmed rather than absent, but don’t buy it for that feature. The full Amazon Smart Thermostat review covers its C-wire and Alexa trade-offs.
Buy it if your heat pump has electric backup, you have a C wire or will use the adapter, and your household is on Alexa. Skip it if the system is dual fuel, or controlling aux heat by outdoor temperature is the reason you’re upgrading.
Aux heat, emergency heat and lockouts in plain terms
Auxiliary heat is supplemental heat the thermostat brings on automatically when the heat pump alone isn’t meeting the setpoint. In many homes it is electric resistance strip heat; in a dual-fuel system it is a furnace. Emergency heat is a mode you select deliberately to run the backup heat on its own.
Lockouts are outdoor-temperature rules. An aux lockout keeps backup heat off above a chosen outdoor temperature, so strip heat doesn’t run on a mild afternoon just because someone raised the setpoint. A compressor lockout, which Sensi calls a balance point, stops the heat pump below a chosen outdoor temperature and hands heating to the backup. The Bonneville Power Administration’s lockout reference, listed in the sources, explains how lockout controls are used to limit strip-heat operation.
The right values depend on the heat pump’s rated operating range, the house and the backup heat source, which is why this guide doesn’t recommend numbers. The four picks differ mainly in who sets them: you or your installer (ecobee, Sensi), the thermostat’s algorithm (Nest, except on dual fuel), or nobody on the evidence found here (Amazon).
None of these features guarantees a lower bill; they change which heat source may run and when. To see whether strip heat actually runs, separate circuit readings for the heat strips are more direct than a thermostat’s runtime chart, as the guide to investigating HVAC runtime with energy data explains.
When a wall thermostat is the wrong purchase
- Ductless mini-splits controlled by an infrared remote usually call for a remote-style controller rather than a 24V wall thermostat. The Sensibo Air Pro review walks through that remote-compatibility check.
- Electric baseboard heat runs on line voltage, and none of these four is designed for it. Use the electric-baseboard smart thermostat picks instead.
- Proprietary communicating systems can lose functions with any third-party thermostat. The HVAC manufacturer’s guidance comes before any checker result.
- A furnace with central air and no heat pump doesn’t need this shortlist; the beginner smart thermostat picks cover that simpler case.
If a smart-home hub will run the thermostat, keep staging and lockouts in the thermostat’s own settings; the standalone versus hub-controlled thermostat comparison explains why.
Sources consulted
- Google: Nest Learning Thermostat (4th gen) specs and wiring compatibility
- Google Nest Help: Heat Pump Balance
- ecobee: threshold settings for ecobee thermostats
- ecobee: Smart Thermostat upgrade and compatibility guide
- Sensi: aux heat settings
- Bonneville Power Administration: lockout and balance point reference (PDF)
Specifications and product identities were compiled through web search on September 29, 2026 and should be confirmed on the seller’s page for your exact size, color, and version. This is researched buyer analysis without hands-on testing.
FAQ
Do I need a special thermostat for a heat pump?
You need one whose maker confirms your heat-pump configuration: the reversing valve, compressor stages, aux and emergency heat, and any furnace backup. Many smart thermostats support heat pumps, but aux-stage limits and dual-fuel support differ by model.
What is the difference between auxiliary heat and emergency heat?
Auxiliary heat is backup heat the thermostat adds automatically when the heat pump needs help. Emergency heat is a mode you choose to run the backup heat by itself, typically while the heat pump is out of service.
Can a smart thermostat control a dual-fuel heat pump?
Some can. ecobee lists dual-fuel systems as compatible, and Nest supports them with a manual lockout temperature instead of Heat Pump Balance. The Amazon Smart Thermostat does not support dual fuel.
Will a smart thermostat work with a ductless mini-split?
Usually not as a wall-thermostat swap. Many mini-splits take commands from an infrared remote, so the common smart upgrade is a remote-style controller; confirm your indoor unit in that controller maker’s checker.