Most smart thermostats are sold to people who have never thought about where the heat actually comes from. That is a mistake when a heat pump is involved, because the difference between a thermostat that runs your compressor properly and one that treats it like a furnace is the difference between efficient heating and paying to make cold air warm. We spent weeks reading installer threads, wiring guides and product documentation to work out which units genuinely handle a heat pump, and the eight below are the ones that do it honestly.
Here is the short answer. The Sensi Smart Thermostat ST55 is the best smart thermostat for heat pumps because it is rated for heat pump systems outright, installs without a C-wire on most existing wiring, and carries a 4.4 star average across more than 23,000 reviews. It handles two-stage heat pump systems, includes no learning gimmicks you have to train, and comes from Copeland, a company that makes compressors rather than phone apps.
The rest of this roundup covers the Nest Learning Thermostat for people who want automation, the Honeywell Lyric T6 Pro for real multi-stage control, two ecobee models for sensor-driven comfort, and cheaper options for simpler homes. Every pick below is written from the manufacturer documentation and the review record, not from spec-sheet marketing.
If you are still deciding how much a thermostat matters, our guide to smart thermostats for home studios covers the scheduling side in more detail. For the heating hardware itself, we have covered heat press machines and foot spas with heat, which share the same idea: the device has to match the job.
One thing to know before you read further is that no mainstream smart thermostat in this group publishes a dedicated auxiliary heat lockout slider the way a boiler control does. What they do offer is system configuration menus where you tell the thermostat what equipment it is attached to, and from that it decides when to call for backup heat. We tell you below exactly what to look for in each one so you are not relying on guesswork.
This roundup was updated for 2026, and everything below reflects the documentation and review record as it stands now.
Table of Contents
- Top 3 Picks for Heat Pumps in 2026
- All 8 Best Smart Thermostats for Heat Pumps at a Glance (October 2026)
- 1. Sensi ST55 Smart Thermostat – The Best All-Round Pick for Heat Pumps
- 2. Google Nest Learning Thermostat 4th Gen – Best for Automation
- 3. Honeywell Lyric T6 Pro Wi-Fi – Best for Two-Stage Heat Pumps
- 4. ecobee Smart Thermostat Enhanced – Best for Occupancy Sensing
- 5. ecobee Smart Thermostat Premium – Best for Room Sensors
- 6. Google Nest Thermostat – Best for Set It and Forget It
- 7. Sensi Lite Smart Thermostat ST25 – Best for First-Time Owners
- 8. Amazon Smart Thermostat – Best for Alexa Homes
- What to Look for in a Smart Thermostat for a Heat Pump
- Auxiliary Heat Explained and How to Set the Lockout
- Five Installation Mistakes That Break Smart Thermostats on Heat Pumps
- Heat Pump System Types and What Each One Needs From a Thermostat
- Smart Home Ecosystem, Matter and Local Control
- Frequently Asked Questions
- Can you put a smart thermostat on a heat pump?
- What type of thermostat is best for a heat pump?
- Why does my thermostat keep saying auxiliary heat?
- At what temperature should a heat pump switch to auxiliary heat?
- Is it bad if auxiliary heat comes on?
- Is ecobee or Nest better for a heat pump?
- Which ecobee thermostat works with a heat pump?
- The Right Thermostat for Your Heat Pump Setup
Top 3 Picks for Heat Pumps in 2026
Sensi ST55 Wi-Fi Thermostat
- Rated for heat pumps
- Works without a C-wire in most installs
- Up to 23% HVAC energy savings
- 3 year warranty
Google Nest Learning 4th Gen
- Auto-scheduling
- Includes room sensor
- Works with most 24V heat pumps
- Matter compatible
Honeywell Lyric T6 Pro
- Supports 2 heat stages and 1 cool
- App control
- Compact familiar design
- Battery powered
All 8 Best Smart Thermostats for Heat Pumps at a Glance (October 2026)
Every thermostat below is rated for heat pump use in the manufacturer documentation. The column that matters most on a heat pump is the C-wire line, because a thermostat that needs 24V constant power will not install cleanly on some older systems without a new wire run.
| Product | Specifications | Action |
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| Sensi ST55 Smart Thermostat |
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| Google Nest Learning Thermostat 4th Gen |
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| Honeywell Lyric T6 Pro Wi-Fi |
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 ecobee Smart Thermostat Enhanced |
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 ecobee Smart Thermostat Premium |
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 Google Nest Thermostat |
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 Sensi Lite Smart Thermostat ST25 |
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 Amazon Smart Thermostat |
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1. Sensi ST55 Smart Thermostat – The Best All-Round Pick for Heat Pumps
Sensi Smart Thermostat, Wi-Fi, DIY, Alexa, Energy Star Certified, ST55
Rated for heat pumps
No C-wire in most installs
24V AC with AA backup
3 year warranty
Pros
- Installs on most two-wire systems without a C-wire
- Rated for heat pump equipment specifically
- Very flexible per-day scheduling
- Shows temperature and humidity on the unit
Cons
- Alert thresholds are fixed and not adjustable
- Some Wi-Fi pairing and connection complaints
- App interface looks dated
The ST55 is the one we kept coming back to while researching this topic, and the reason is unusually specific: its documentation lists heat pump as a supported equipment type rather than as an afterthought. It runs on 24V AC system power with two AA batteries for backup, and the manufacturer states that a common wire, usually called a C-wire, is not required in most applications. On a heat pump install that is the difference between a fifteen minute swap and a trip to the attic for an electrician.
It also handles two-wire systems that most connected thermostats simply refuse, which matters for older heat-only or hydronic installations. Reviewers repeatedly mention that it covered the footprint of the thermostat it replaced, so there was no wall patching. The built in level on the back plate is a small touch that makes a wall-mounted install noticeably easier for a first-timer.
From a heat pump perspective, the honest limitation is that the ST55 does not advertise a dedicated lockout temperature field in its feature list. What it does instead is let you configure the system type in the app, which is how it decides whether to use the heat pump alone or bring in backup heat. If your installer has a specific lockout figure in mind, raise it before you buy, because you may end up setting it during commissioning rather than in the app.
The scheduling side is genuinely strong for a button-style thermostat. Each day can be set independently, and you can copy a working day and swap it for a different one, which is how most households actually use schedules. It also displays relative humidity, which is helpful if you are trying to understand why a heat pump is running the compressor and the blower together for a dehumidification call.
Who the Sensi ST55 suits
It suits households with an existing heat pump that wants a clean swap without new wiring, and anyone who finds learning thermostats annoying. Owners of older systems with an unusual wire count are the biggest winners, because the ST55 accepts wiring that several premium units will not.
It also suits anyone who prefers physical buttons to a touchscreen, particularly if the thermostat is being used by an older family member. The form factor is deliberately conventional, which is a virtue in a device mounted in a hallway.
Who the Sensi ST55 does not suit
It does not suit someone who wants a built in humidity readout that they can adjust thresholds on, because the alert limits are fixed at the factory. Remote monitoring of a vacant property is a weak point for that reason.
Reviewers also report occasional Wi-Fi pairing problems and slow technical support response times. If your household depends on the app for daily control, that friction is worth weighing before you commit.
2. Google Nest Learning Thermostat 4th Gen – Best for Automation
Google Nest Learning Thermostat (4th gen) + Nest Temperature Sensor (2nd gen) – Obsidian
Learning schedule
60 percent larger display
Includes room sensor
Matter compatible
Pros
- Learning builds a schedule in about a week
- Included sensor meaningfully improves comfort
- Adaptive Eco uses outdoor temperature
- Works with most 24V heat pumps
Cons
- Not ENERGY STAR certified so rebate eligibility is limited
- Backplate is not compatible with third gen Nest
- Setup app can report no power on the R wire
On paper this is the most capable learning thermostat on the market, and the fourth generation is a real step up from what came before. The display is 60 percent larger than the previous model and uses a line of sight temperature reading to show the temperature where you are standing rather than where the unit is mounted. The trim and body are aluminium, and reviewers consistently describe the dial action as precise.
For heat pump owners the important part is the sensor, not the dial. The bundle includes a second generation Nest Temperature Sensor, and the thermostat can prioritise any room in the house rather than the hallway where the thermostat happens to be mounted. On a two-stage heat pump, keeping the occupied room at setpoint means stage two runs less often, which is the point of the machine in the first place.
Adaptive Eco uses the outdoor temperature to choose an away setpoint and then restores comfort within about an hour of you returning. That recovery behaviour matters on a heat pump, because a system that has been idling for a morning comes back to a cold house and has to close the gap with the compressor first. Nest also asks permission before changing your schedule rather than silently editing it, which some owners love and others find irritating.
The critical caveat for heat pump installs is power. The documentation says the Nest Learning Thermostat works with most 24V systems including heat pumps and that no C wire is needed in most homes, but owners of 24V systems without a C wire report the setup app declaring there is no power on the R wire. Reviewers also note the unit is not ENERGY STAR certified, which removes it from many utility rebate programmes.
Who the Nest Learning Thermostat suits
It suits people who want the thermostat to program itself and then stop thinking about it, and households with uneven temperatures where one room is clearly the one you actually live in. The included sensor is the reason, and it is the single most-cited praise across thousands of reviews.
It also suits households already invested in Google Home or Apple Home, since it supports both alongside Alexa and Google Assistant. If you plan to add sensors in a second or third room later, the architecture already supports it.
Who the Nest Learning Thermostat does not suit
It does not suit anyone chasing a utility rebate, because the lack of ENERGY STAR certification disqualifies it from many programmes. Anyone with a thermostat location that reads warm will also find the eco temperature runs a little higher than they prefer.
Owners upgrading from a third generation Nest should know the backplate is not compatible, so this is a full replacement rather than a swap. It is also US-only hardware and will not work with UK or EU boiler systems.
3. Honeywell Lyric T6 Pro Wi-Fi – Best for Two-Stage Heat Pumps
Honeywell TH6220WF2006/U Lyric T6 Pro Wi-Fi Programmable Thermostat with Stages Up to 2 Heat/1 Cool Heat Pump or 2 Heat/2 Cool Conventional
Supports 2 stage heat and 1 stage cool
Also 2 heat 2 cool conventional
2 AA battery powered
App control
Pros
- Explicit multi-stage heat pump support
- Compact familiar form factor
- Dependable mid-range build
- Programmable with app remote control
Cons
- No room sensor support at all
- Fewer smart home integrations
- No learning or occupancy sensing
The Lyric T6 Pro is the least glamorous pick here and possibly the most correct one for a two-stage heat pump. The manufacturer rates it for stages up to two heat and one cool on heat pump systems, and it also handles two heat and two cool conventional systems. That explicit rating is the whole argument: the thermostat is designed around equipment that has a second stage of heat to manage.
Honeywell Home equipment shows up constantly in installer recommendations for heat pump work, and the reason is that the settings menu exposes configuration options rather than hiding them behind a learning algorithm. When an HVAC technician needs to set a staging differential or confirm how the system is wired, a screen with those options beats a consumer app that assumes one furnace.
It is a small unit, 5 by 2.3 by 6 inches and about 4 ounces, and it runs on two AA batteries with 24V AC system power. Reviewers describe installation as clean and the schedule as straightforward once the app is paired. The 4.4 average sits across more than 2,600 ratings with roughly 74 percent at five stars, which is a solid, unremarkable consistency.
What you give up is obvious. There is no room sensor option, no occupancy sensing, no learning, and fewer smart home integrations than the ecobee or Nest units. On a large house with a heat pump, that means the thermostat makes its decision from the temperature at its own location, and no amount of configuration fixes that.
Who the Lyric T6 Pro suits
It suits someone on a two-stage heat pump who wants the thermostat to speak the same language as the equipment, particularly if an HVAC contractor installed the system and expects to fine-tune it. The multi-stage rating is stated in the documentation rather than inferred.
It also suits a household that wants scheduling and remote control without a learning phase and without subscriptions. The feature list is short enough that you will understand everything on the screen.
Who the Lyric T6 Pro does not suit
It does not suit anyone with a large or unevenly heated house, because there is no way to add a room sensor. No sensor means no room-by-room balancing, and on a two-stage machine that is a real comfort loss rather than a minor one.
It also does not suit a household that wants voice control through a broader smart home platform, since integrations are limited compared with the ecobee and Nest lines.
4. ecobee Smart Thermostat Enhanced – Best for Occupancy Sensing
ecobee Smart Thermostat Enhanced, Programmable Wifi Thermostat
90 percent system compatibility
Built in occupancy sensor
Power extender kit included
3 year warranty
Pros
- Preheats the home before you arrive
- Works with 90 percent of HVAC systems
- Power Extender Kit solves most no C-wire homes
- Polished app with energy views
Cons
- SmartSensors cost extra
- Power Extender Kit adds install complexity
- No air quality monitor or speaker
The Enhanced model is the middle of the ecobee range and the one most heat pump owners should actually buy. It is rated for compatibility with roughly 90 percent of HVAC systems, which includes heat pumps, and the list of supported equipment types runs from air conditioners and boilers to furnaces, heat pumps and humidifiers. That breadth is not marketing, it is the compatibility check the app runs during setup.
The differentiator over the cheaper units is the built in occupancy sensor. It uses radar to detect that you are approaching the house and starts heating before you arrive, so the heat pump is ramping up while you are still parking rather than after you walk in. On a cold morning that is the difference between a comfortable arrival and fifteen minutes of waiting, and it reduces the temptation to crank the setpoint up by hand.
It is ENERGY STAR certified and ecobee quotes savings of up to 26 percent per year on heating and cooling costs. The eco+ feature folds your routine, your stated comfort preferences, local weather and grid activity into its decisions, which is a smarter version of the same idea every learning thermostat is selling.
For installs without a C wire, a Power Extender Kit is included in the box, along with a trim plate and wire labels. That solves the power problem but does add steps to the wiring, and some owners report finding it more involved than a straight swap. The unit itself is a black metal rectangle with a 4 inch LCD and a 3 year manufacturer warranty.
Who the ecobee Enhanced suits
It suits households with a schedule that is unpredictable, because occupancy sensing handles the arrive and leave transitions without you programming them. It also suits anyone who wants eco features that respond to weather and grid conditions rather than a fixed weekly timetable.
It suits people upgrading from a builder grade thermostat in a home without a C wire, since the extender kit is in the box. Reviewers consistently rate the app highly for schedule, system activity and energy views.
Who the ecobee Enhanced does not suit
It does not suit anyone who needs room-by-room comfort, because the SmartSensors that provide it are sold separately. That additional cost is the single most common complaint across the reviews and it changes the effective price of the system.
It also does not suit anyone who wants air quality monitoring or a built in voice speaker, since both are reserved for the Premium model. Buyers paying for those headline features should step up rather than settle.
5. ecobee Smart Thermostat Premium – Best for Room Sensors
ecobee Smart Thermostat Premium – WiFi, Siri & Alexa Built-In, Smart Sensor
Includes a SmartSensor
95 percent system compatibility
Built in air quality monitor
3 year warranty
Pros
- Bundled room sensor solves hot and cold spots
- Radar occupancy sensing preheats reliably
- Air quality alerts and filter reminders
- Compatible with 95 percent of systems
Cons
- Several features need a paid subscription or extra hardware
- Siri support needs an Apple home hub
- Highest cost in this group
The Premium is the only unit in this roundup that ships with a room sensor in the box, and on a heat pump that is not a minor accessory. A ducted system delivers air to the far end of the house, so the temperature at the hallway thermostat is rarely the temperature in the room you are sitting in. The bundled SmartSensor lets you target a specific room, and that is how you keep a two-stage compressor from running stage two to satisfy a hallway reading.
It is rated for compatibility with about 95 percent of HVAC systems, and the supported equipment list is the longest here, including air conditioners, boilers, dehumidifiers, electric baseboard heaters, furnaces, heat pumps and humidifiers. A Power Extender Kit and trim kit are included for homes without a C wire.
It also carries a built in air quality monitor that raises drop alerts and reminds you about furnace filter changes, which is genuinely useful on a heat pump because a clogged filter shows up as a running cost problem before it shows up as a comfort problem. The 4.3 average sits across more than 4,100 ratings with 73 percent at five stars, so the review base is large enough to trust.
Be honest about the extras, though. The smart speaker works with Alexa built in, and Siri needs an Apple home hub in addition to the thermostat. Two-way talk and the live front door view require an ecobee Smart Doorbell Camera, and smoke alarm sound detection needs a Smart Security subscription. Those are subscription-gated features on a device you already paid a premium for.
Who the ecobee Premium suits
It suits anyone in a house where rooms differ, and that is most two-storey homes. The included sensor is the difference between a system that fights you and one that follows the room you use. Reviewers single it out as the reason their comfort improved.
It also suits households that want filter reminders and air quality alerts, and people who want voice control from the thermostat itself rather than a separate speaker. The radar occupancy sensing is described as noticeably more reliable than earlier ecobee generations.
Who the ecobee Premium does not suit
It does not suit anyone who objects to subscription features appearing in a product description, since several headline capabilities are gated. It also does not suit an Apple household without a home hub who expects Siri to work out of the box.
It is the highest cost unit in this group, and the honest question is whether you would use the air quality monitor and the speaker. If not, the Enhanced model gives you the heat pump relevant features for less.
6. Google Nest Thermostat – Best for Set It and Forget It
Google Nest Thermostat – Smart Thermostat for Home – Programmable Wifi Thermostat – Charcoal
ENERGY STAR certified
Geofencing auto away
Savings Finder suggestions
Matter certified assistants
Pros
- Most reviewed thermostat in this group
- Learning builds a usable schedule in about a week
- Geo-location and motion sensing make away mode reliable
- Real reported savings on heating
Cons
- C wire often needed on heat pump systems
- Poor behaviour when internet drops
- Only a 1 year warranty
This is the highest volume reviewed thermostat in the group, with close to 30,000 ratings, so the review record is unusually reliable. It sits at a 4.1 average, which is the lowest of the ecobee and Nest premium units, and the distribution explains why: two thirds are five stars, but 13 percent are one star. That gap is almost entirely about power wiring and connectivity rather than about the concept.
Auto-away uses geolocation plus a motion sensor to turn the system down when the house is empty, which is genuinely useful and requires no schedule from you. Savings Finder then suggests schedule tweaks for extra savings. HVAC monitoring sends alerts and maintenance reminders, and it supports optional temperature sensors for rooms away from the unit.
The part that matters most for a heat pump is the power requirement. The documentation is unusually honest about it: the unit is designed to work without a C wire in most homes, but heating-only, cooling-only, zone controlled and many heat pump systems may require a C wire or a compatible power accessory. Buyers who found that out after ordering report it as the single most disappointing thing about the product.
Its other weak point is what happens when the internet goes down. Reviewers describe app functions degrading sharply, devices showing as offline, and recovery requiring removal and a fresh barcode scan. It also carries only a 1 year warranty, the shortest in this group, against 3 years on the Sensi and ecobee units.
Who the Google Nest Thermostat suits
It suits households that want away mode to handle the empty part of the day and barely want to program anything else. It also suits anyone who wants a thermostat that works with every Matter-certified voice assistant rather than a single ecosystem.
It suits buyers who want a second temperature sensor later without changing thermostats, and people who are comfortable troubleshooting connectivity because it is the most widely reviewed and therefore the best documented.
Who the Google Nest Thermostat does not suit
It does not suit owners of a heat pump system that needs a C wire and has no accessible one, which is a common combination in older homes. Check that before you buy, not after.
It also does not suit anyone who needs the thermostat to keep working through an internet outage, and anyone who values warranty length. Reviewers also find the ring interface confusing for less technical users and the setup wizard longer than necessary.
7. Sensi Lite Smart Thermostat ST25 – Best for First-Time Owners
Sensi Lite Smart Thermostat, WiFi, Alexa, DIY, Energy Star Certified, ST25
C-wire required for heat pumps
Large touchscreen display
23 percent energy savings claim
3 year warranty
Pros
- Install often takes 10 to 15 minutes
- App checks wire compatibility before you buy
- Large numbers are easy to read
- Slow-start feature reduces HVAC wear
Cons
- C-wire is required on heat pump systems
- Intermittent Wi-Fi dropouts
- Monochrome LCD rather than a colour screen
The Lite is the simpler Sensi, and the one thing you need to know before anything else is that it requires a C-wire for heat pump and heat/cool only systems. That is a real constraint, and it is the opposite of what the ST55 manages. If you have a C wire or can have one run, this is a clean first smart thermostat.
What it does well is installation and clarity. The app lets you check wire compatibility before you buy or install, which removes most of the guesswork and the risk of a return. The back plate has a built in level, and owners report completing the install in ten to fifteen minutes. The touchscreen uses one touch for mode and arrows for temperature, which is about as simple as a touch interface gets.
Temperature accuracy is a genuine strength. Reviewers compared it against reference thermometers and found readings within about half a degree, and the large numeric display is easy to read for older users. The slow-start feature eases the system into the set temperature rather than firing the compressor at full tilt, which reduces wear on a machine you rely on every winter.
Its 4.0 average across 2,347 ratings carries a comparatively high 16 percent one-star share, and the pattern is consistent: intermittent Wi-Fi dropouts, app failures when scanning for 2.4 GHz networks that require manual entry, and a monochrome LCD instead of the colour screen on higher tier models. The location based features also work only in the US and Canada.
Who the Sensi Lite suits
It suits first-time smart thermostat owners who want something that will not confuse anyone in the house. Large numbers, one-touch mode changes and a plain menu mean the whole family can use it without training.
It also suits anyone replacing an older thermostat on a system that already has a C wire, and anyone who wants scheduling, geofencing and usage reports without a learning phase. The 3 year warranty is a good length for the money.
Who the Sensi Lite does not suit
It does not suit owners of a heat pump in a home without a C wire. In that situation the ST55 is the correct product in the same family, and swapping between them is a small change from this list.
It does not suit anyone on a weak or crowded home network, because the app’s 2.4 GHz scanning is the most common failure point in the reviews. Nor is it a good fit if you want a colour display or more advanced on-device scheduling.
8. Amazon Smart Thermostat – Best for Alexa Homes
Amazon Smart Thermostat, Save money and energy, Works with Alexa and Ring, C-wire required
C-wire required
Alexa comfort zones
ENERGY STAR certified
Honeywell Home technology
Pros
- Comfort zones tied to Alexa presence detection
- Alexa app guides installation step by step
- Home away and sleep schedules
- Works with Ring and the Alexa ecosystem
Cons
- C-wire required with no power kit listed
- No learning and no multi-room sensors
- Control depends on the Alexa app and internet
Amazon built this thermostat on Honeywell Home technology, which matters more than it sounds. The same industrial base that makes the Lyric line is doing the control work here, so the underlying equipment handling is not the weak point. The 4.0 average sits across nearly 25,500 ratings, the second largest review base in this group, so the pattern of complaints is well established.
Its distinguishing feature is comfort zones. You connect the thermostat to selected Alexa devices and it adjusts heating and cooling based on temperature readings or presence detection, so the house responds to whether anyone is actually home. It is also ENERGY STAR certified, and Amazon sends details about local thermostat rebates after purchase, which is a small but genuinely useful nudge.
The install path runs through the Alexa app step by step, with home, away and sleep schedules available out of the box. Reviewers consistently call the guided setup easy and the schedule configuration simple. If you already have Ring cameras and Alexa speakers, the ecosystem fit is the strongest argument for this unit.
The constraint is that a C-wire is required, and unlike the ecobee units there is no power extender kit listed in the box. A home without one needs an adapter or professional wiring, which changes the cost picture entirely. Beyond that, the feature set is narrower than the premium rivals, with no learning, no multi-room sensors and no air quality monitoring.
Who the Amazon Smart Thermostat suits
It suits households that are already running an Alexa home and want the thermostat inside the same app as everything else. Presence detection through Alexa devices means the away logic needs no thought at all, and the installation walkthrough is the clearest of any unit here.
It also suits buyers who want a low-friction path to rebates, since Amazon surfaces local programmes after purchase. The three built-in schedules are enough for most homes without any customisation.
Who the Amazon Smart Thermostat does not suit
It does not suit owners of a heat pump in a home without a C wire, because there is no power kit in the box to bridge the gap. Check your wiring first.
It does not suit anyone outside the Alexa ecosystem, or anyone who needs the thermostat to work independently of an internet connection. The advanced automatic control features also depend on which Alexa account features are available in your region.
What to Look for in a Smart Thermostat for a Heat Pump
A heat pump does one thing that no other heating appliance does: it moves heat rather than generating it, and it does that efficiently only within a temperature window. The right thermostat for your system is the one that understands that window and does not help the equipment fall out of it. Here are the seven things that decide whether a unit is genuinely heat pump capable or merely sold near one.
1. Explicit heat pump equipment support. The manufacturer’s documentation should name heat pump as a supported equipment type, the way the Sensi ST55, the ecobee models and the Amazon unit all do. A thermostat that only lists air conditioner, furnace and boiler in its supported equipment list is telling you something. This is the first filter to apply and it eliminates options immediately.
2. Two-stage or variable speed capability. A two-stage compressor has a low output stage and a high output stage, and a variable speed unit ramps continuously between them. The thermostat decides when to demand more capacity, and a unit that cannot express that decision will either run the second stage constantly or lock it out entirely. The Honeywell Lyric T6 Pro states its stage support plainly, which is why it appears here despite being the least feature-rich product in the group.
3. Configurable backup heat behaviour. This is the aux heat lockout question, and it is the one that changes your electricity bill. No mainstream smart thermostat in this list advertises a dedicated lockout temperature slider the way a boiler control does, so what you are looking for is a system configuration menu where you can tell the thermostat what backup heat is attached and how the two stages relate. Ask the installer to set it during commissioning, because the default is rarely right for a heat pump.
4. C-wire situation. The common wire carries constant 24V power to the thermostat so it can run a Wi-Fi radio and a colour display without draining batteries. A heat pump is usually installed on 24V AC power, which makes this simpler than a boiler, but many older systems still lack the wire. The Sensi ST55 is the standout here because the manufacturer states the C-wire is not required in most applications, while the Sensi Lite and the Amazon Smart Thermostat both require it outright, and the Nest Thermostat requires it or a power accessory on many heat pump systems.
5. Room sensors. A ducted heat pump moves air through registers, so the reading at the thermostat is rarely the reading where you live. If your house has a hot or cold spot, a thermostat that can prioritise a remote sensor will run stage two less often. Only the ecobee Premium includes a sensor in the box, and the ecobee Enhanced and Nest models support sensors sold separately.
6. ENERGY STAR certification and rebates. This is unglamorous and it pays. Certified thermostats are commonly the qualification for utility rebates and demand response programmes, and the Nest Learning Thermostat being uncertified is a real drawback for anyone chasing one. Check your utility’s approved equipment list before you buy, because approval lists are not always the ones you would guess.
7. Recovery time and setback depth. Heat pumps recover slowly after a deep setback, and geothermal owners in particular tell us to keep setbacks to about two degrees because the system cannot catch up overnight. A thermostat that lets you program an aggressive overnight setback will make your house uncomfortable by morning on a cold night. This is a programming habit rather than a product feature, but the thermostat’s schedule design shapes whether you keep the habit.
Auxiliary Heat Explained and How to Set the Lockout
Auxiliary heat, also called strip heat, emergency heat or backup heat, is the electric resistance heater that came with your heat pump as a backup. Where the heat pump moves heat from outdoors to indoors using a refrigerant cycle, the auxiliary heat is a row of resistance elements that make heat the old, expensive way. Electricity converts directly to heat in a resistance element, which is why it costs several times more per hour of warmth than the compressor does.
On a mild day a heat pump can hold a setpoint of 70F with outdoor temperatures well down into the twenties. As the outdoor temperature falls, the amount of heat the outdoor coil can absorb falls, and the amount of heat the indoor coil can deliver falls with it. The outdoor temperature at which the heat pump can no longer supply the heat the house needs is called the balancing point. Below that point the compressor runs flat out and still falls short, which is when backup heat has to take over.
Auxiliary heat lockout is the setting that decides how far below the balancing point the heat pump is allowed to work before the thermostat calls for backup. Set it too high, at say 50F, and the thermostat will hand the job to expensive strip heat on a day when the compressor was coping perfectly well. Set it too low, at 5F, and the heat pump will run continuously without ever keeping up, leaving you cold and still paying compressor rates for a house that never reaches setpoint. This is exactly the balance that installer advice on HVAC-Talk keeps circling: run the heat pump down to fairly low temperatures with electric backup, and only lock it out when the compressor is barely putting out heat.
A long-term heat pump owner we found in the forum discussions framed it the same way after 13 years of running heat pumps: review the aux heat lockout temperature specifically, because the strips come on prematurely. That is the single highest value action in this entire article, and it costs nothing.
If your thermostat keeps announcing auxiliary heat, work through these four checks in order. First, confirm the system is configured as a heat pump rather than a conventional system, because the wrong system type changes how staging is handled. Second, check the lockout or balancing point value against your climate and the size of the backup heat. Third, look at whether stage two is being called constantly, which points at a sizing problem or a refrigerant charge issue rather than a thermostat fault. Fourth, if the backup heat runs almost continuously, ask your installer to check whether the ductwork is delivering enough air, because a starved system reaches setpoint less often and calls for backup more.
One more variable is where the outdoor temperature reading comes from. The thermostat is inside your house, so most of them rely on the equipment’s own outdoor sensor or a remote weather feed to decide when to engage heat strips. If your thermostat is making a poor decision, the first question is where its outdoor data is coming from.
Five Installation Mistakes That Break Smart Thermostats on Heat Pumps
1. Setting the reversing valve position wrong. A heat pump uses a reversing valve to run the refrigerant flow in reverse for cooling. The thermostat has to energise the O or B terminal correctly for heat mode, and if that is configured backwards the system heats when you asked for cooling and cools when you asked for heat. This is the single most alarming failure mode in the forum record, and users report that configuration changes sometimes appear not to stick, which usually means the change was saved on the wrong system profile.
2. Leaving out the second stage wire. A two-stage heat pump needs a W2 or Y2 control wire from the equipment to the thermostat. Without it, the thermostat can only call for the first stage, and you are paying for a two-stage machine and using half of it. Check the terminal labels on your indoor unit before the old thermostat comes off, and photograph the existing wiring.
3. Skipping the C-wire decision. Decide before you buy whether you have a C wire, because the products in this roundup split cleanly on that. The Sensi ST55 generally does not need one, the Sensi Lite and the Amazon Smart Thermostat do, the ecobee models include a power extender kit, and the Nest units are conditional. Guessing wrong here is the most common reason a heat pump thermostat gets returned.
4. Selecting the wrong system type in setup. Choosing conventional instead of heat pump, or the wrong number of stages, changes how the thermostat sequences calls for heat. This is also the setting that determines whether an auxiliary heat lockout value is even offered to you. Getting it right is a two minute job that changes the behaviour of the whole system.
5. Locking out the second stage too aggressively. This is the installer complaint that sits behind the reputation problem some brands have. Letting a thermostat manage staging is usually a good thing, but locking out the second stage too early generates comfort complaints and call-backs, because the house cannot hold temperature when the first stage is not enough. If you are an installer, a sensible starting point is to let the heat pump work down to fairly low outdoor temperatures with electric backup and only lock it out when it is barely producing heat.
Heat Pump System Types and What Each One Needs From a Thermostat
Before choosing a thermostat it helps to know which kind of system you actually have, because the answer changes what the thermostat has to do. There are three common arrangements, and the differences are not cosmetic.
Heat pump with electric auxiliary heat. This is the most common arrangement in areas where electricity is the only available fuel. The heat pump handles the heating load down to its balancing point, and a bank of resistance elements covers the rest. This is the arrangement where the auxiliary heat lockout matters most, because a poorly set lockout means paying resistance prices for heat the compressor could have produced. It is the system we have assumed throughout this guide.
Dual-fuel, meaning a heat pump backed by a gas furnace. Here the backup is a furnace rather than strip heat, which changes the economics completely. Gas is cheap relative to electric resistance heat, so a thermostat that lets the furnace take over sooner is far less costly than the same behaviour on an all-electric system. The dual-fuel setup also needs a thermostat that can sequence two entirely different heat sources, and the changeover point is usually set by the installer rather than by the homeowner.
Mini-split, ducted or unducted. A ducted mini-split installed in existing ductwork can often use a conventional wall thermostat, but a wall-mounted or ceiling cassette unit usually ships with its own recessed controller with a proprietary remote sensor. There is no standard wall terminal to attach a smart thermostat to. If that is your situation, the smart thermostat decision moves to the controller that came with the machine, and no roundup listing will change that.
There is a fourth variant worth flagging because it causes real problems: heat pumps paired with an oil-fired burner. Forum users report that newer Wi-Fi thermostats will not work with that arrangement at all, which turns a routine upgrade into a bigger job. If your backup heat is oil rather than electricity or gas, raise it with your installer before purchasing anything.
Smart Home Ecosystem, Matter and Local Control
Once the equipment settings are right, the second question most buyers ask is what the thermostat talks to. This matters more than usual in this category because every unit here is a Wi-Fi device, and a Wi-Fi device that depends entirely on a vendor’s cloud is a device you stop being able to use when that vendor changes something.
The mainstream options split cleanly. The Nest Learning Thermostat is Matter compatible and works with every Matter-certified voice assistant, which makes it the least platform-bound of the group. The Google Nest Thermostat is also Matter certified. Both ecobee models work with Amazon Alexa, Google Assistant, Apple HomeKit and SmartThings, and the Premium can be queried by Siri when you have an Apple home hub alongside it. The Sensi models work with Alexa, Google Assistant, SmartThings, and on the ST55 also Apple HomeKit and Vera. The Amazon Smart Thermostat sits inside the Alexa ecosystem by design and pairs with Ring.
One genuine differentiator worth noting is privacy posture. Sensi states in its own product material that it will not sell your personal information to third parties, or use thermostat activity data for targeting or advertising. That is a marketing claim, and we treat it as one, but it is unusual to see it stated plainly on a smart thermostat listing rather than buried in a policy page.
For anyone running Home Assistant, the honest answer is that a mainstream consumer thermostat gives you limited local control. Several options here work with SmartThings, which adds an automation layer without a local radio protocol, but a thermostat that will only accept commands through a vendor cloud is a poor foundation for a system built around not depending on vendor clouds. If local control is a hard requirement for you, the decision is less about which of these eight to buy and more about accepting that a different product category, with its own trade-offs, is the better fit.
There is one more integration angle specific to heat pumps and mini-splits. A ducted mini-split installed alongside existing ductwork may not come with a conventional wall thermostat at all, since many factory controllers are recessed or mounted in a hidden panel. Several of the thermostats here cover a mini-split use case as part of a single system rather than as a separate device, which is worth confirming with the equipment’s installation manual before you shop.
Frequently Asked Questions
Can you put a smart thermostat on a heat pump?
Yes, in almost every case. All eight thermostats in this roundup are rated for heat pump equipment, and a ducted heat pump runs on standard 24V AC control power just like a furnace. The two things to verify first are whether you have a C-wire available, and whether your system is two-stage or single-stage, because that determines which terminals you need and whether the thermostat can manage the second stage. Mini-splits need a different approach entirely, since they ship with their own controller.
What type of thermostat is best for a heat pump?
A thermostat with explicit heat pump equipment support, a configurable system type, and clear second-stage handling. On a heat pump with electric backup, the single most valuable feature is a way to set the auxiliary heat lockout so the compressor works down to low outdoor temperatures before resistive heat takes over. A unit with room sensor support is the next most useful thing, because it stops the thermostat from calling for extra heat based on a hallway reading.
Why does my thermostat keep saying auxiliary heat?
Work through four checks in order. Confirm the system is set up as a heat pump with the correct number of stages, then check the lockout or balancing point value against your climate. If stage two runs constantly, that points to duct airflow or system sizing rather than the thermostat. And if backup heat runs nearly all the time, ask your installer to confirm enough air is reaching the registers.
At what temperature should a heat pump switch to auxiliary heat?
For most homes with electric strip heat, run the heat pump as low as it will comfortably go and only lock out auxiliary heat when the compressor is barely producing heat, which on a typical cold-climate system means somewhere around 20F to 25F outdoor. In a mild climate with a well-sized machine, switching closer to 35F to 40F is reasonable. A lockout set much higher than this hands the job to expensive resistive heat on nights the compressor was handling fine.
Is it bad if auxiliary heat comes on?
Occasional use during the coldest hours is exactly what backup heat is for. It becomes a problem when it runs far more often than expected, because resistive heat costs several times more per hour than the compressor. Most of that waste comes from a lockout temperature set too high, or from a system that is short on airflow and cannot hold setpoint on the compressor stage alone. Both are fixable.
Is ecobee or Nest better for a heat pump?
The ecobee models give you more control over the equipment itself and the Premium ships with a room sensor in the box, which helps a two-stage compressor stop calling for extra heat based on a hallway reading. The Nest Learning Thermostat is better if you want the schedule to build itself and you care about Google Home, but it is not ENERGY STAR certified, which limits rebate eligibility. On a heat pump with electric backup, the ecobee side has the edge for room-level control.
Which ecobee thermostat works with a heat pump?
All three ecobee models support heat pumps. The Smart Thermostat Premium and Smart Thermostat Enhanced both list heat pump among their supported equipment types and both include a power extender kit for homes without a C wire. The Premium adds a bundled room sensor, an air quality monitor and a built in speaker. The Enhanced is the one most heat pump owners should buy, because the features you actually need on a heat pump are already in it.
The Right Thermostat for Your Heat Pump Setup
The best smart thermostats for heat pumps are not the ones with the longest feature lists, they are the ones that tell your equipment what it is and then let the compressor do its job. Our Sensi ST55 takes the top slot because it is rated for heat pump equipment, works without a C-wire in most installs, and has the deepest, most consistent review record of anything we looked at.
Match the rest to your situation. On a two-stage system where an HVAC contractor will be commissioning the equipment, go with the Honeywell Lyric T6 Pro, which states its stage support plainly. If you want the thermostat to program itself, the Nest Learning Thermostat is the pick, provided you are not chasing a rebate. If your rooms run uneven, the ecobee Premium with its bundled sensor or the ecobee Enhanced if you want to keep the cost down. If you already live in an Alexa home, the Amazon Smart Thermostat is the simplest path.
And whichever you choose, set the auxiliary heat lockout properly before you finish commissioning. It is the highest value thing in this article and it costs nothing at all. As we noted in our look at the best heat press machines for t-shirts, the tool only performs as designed if you set it up as designed, and the same is true of a heat pump in 2026.