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Amazon Smart Thermostat Review: Cheap, Capable, and Fussy About Wiring

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Wide environmental view of a person adjusting a wall thermostat in a warm hallway, in soft overcast light

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The verdict in 90 seconds

The Amazon Smart Thermostat is the cheapest honest way to get scheduling, remote control and automatic setbacks — provided you have a C wire and live in an Alexa household. It is built on Honeywell Home hardware, it is ENERGY STAR certified, and it delivers the part of the smart-thermostat promise that actually saves money. Its 4.0 owner rating is not a verdict on how it heats a house; it is a verdict on how many people bought it without checking their wiring and how many wanted it to work with Google or Apple. Confirm both before you order and it is very good value.

Wide view of a person adjusting a wall thermostat in a warm hallway, in soft overcast light

What owners consistently praise

The price for what it does. At around 80 dollars it undercuts the Nest and ecobee flagships by roughly two thirds while delivering the same core function: a 7-day schedule, phone control from anywhere, and automatic adjustments. Owners repeatedly make the point that the expensive features in this category are conveniences, not savings mechanisms, and this thermostat skips the conveniences.

The Honeywell underpinnings. Amazon did not design a thermostat from scratch; it commissioned one from Resideo, the company behind Honeywell Home. Owners with HVAC backgrounds note this in reviews, and the practical result is sensible temperature control, quiet relays and a compatibility list that covers conventional gas, oil and electric forced air, heat pumps with auxiliary heat, and standard hot water systems.

Alexa Hunches. This is the feature that surprises people. If Alexa can see from your other devices that everyone has gone to bed or left the house, it nudges the temperature without being asked. Owners who already have Echo devices and smart plugs report that it captures setbacks they would never have programmed, which is precisely where the savings live.

The look. A flat white square with a hidden display is not exciting, but owners consistently describe it as unobtrusive and easy to read from across the room, and the touch controls respond reliably.

Close-up detail of the material being worked in a heating & cooling project, in soft early-morning light

What owners actually complain about

The C wire requirement, by an enormous margin. This dominates the negative reviews. The standard box contains no adapter, and the thermostat simply will not run on a system without a common wire. Because most American homes wired before roughly 2010 lack one, a substantial share of buyers open the box, pull off the old thermostat, and discover the purchase was wrong. Amazon does sell a version bundled with a C-wire adapter — the confusion is that the two listings look nearly identical. Photograph your wiring first.

Alexa app dependence. Everything lives in the Alexa app: schedules, away settings, temperature history. The thermostat itself offers up and down control and little else. Owners report the schedule interface being buried several menus deep, and households where not everyone has the app find the thermostat less convenient than the one it replaced. There is no web interface at all.

Ecosystem lock-in. No HomeKit, no Google Assistant, no SmartThings. This is a frequent reason for returns and it is not going to change.

Hunches acting when you did not want them to. The flip side of the automation. A recurring gripe is the temperature changing without an obvious cause, usually because a Hunch fired or a routine on another device triggered it. It is switchable, but owners describe hunting for the setting.

Connectivity and setup stumbles. A persistent minority report the thermostat failing to complete Wi-Fi setup, dropping off the network after a router change, or needing a factory reset to re-pair. It is 2.4 GHz only, which trips up owners on combined-band mesh networks. And there is no remote sensor option and no geofencing in the conventional sense, so a house with hot and cold rooms is not helped by this thermostat at all.

Who it suits, and who should buy something else

Buy it if you have a confirmed C wire, you already use Alexa, and your goal is the cheapest legitimate scheduling and remote control you can get.

Buy the Sensi ST55 instead if your wiring is old — the Sensi runs without a C wire on most common systems and supports Alexa, Google Assistant and HomeKit at around 100 dollars.

Buy an ecobee instead if one room is always wrong. The Enhanced supports SmartSensors and includes a Power Extender Kit for C-wire-free homes; the Premium ships with a sensor and an air quality monitor.

Buy the Nest instead if your household runs on Google — see our Google Nest Thermostat review. The whole field, ranked, is in our best smart thermostat guide.

Wide view of a person adjusting a wall thermostat in a warm hallway, in warm evening lamplight

Specifications

SpecAmazon Smart Thermostat
ManufacturerBuilt by Resideo (Honeywell Home) for Amazon
Dimensions4.3 x 4.3 x 0.84 in.
C wireRequired; adapter sold in a separate bundle
Scheduling7-day schedule via the Alexa app only
AutomationAlexa Hunches and routines
Remote sensorsNot supported
EcosystemsAlexa only — no HomeKit, Google Assistant or SmartThings
Wi-Fi2.4 GHz only
CertificationENERGY STAR, with a claimed 8 percent saving
Warranty1 year limited

The bottom line

This is a well-made budget thermostat wearing a rating earned mostly by mismatched expectations. If your wall has a C wire and your house runs on Alexa, it does the job the 250 dollar models do, minus the sensors and the learning, for a third of the money. If either of those two conditions fails, it will be a return — and there is a better-suited thermostat at a similar price for almost every alternative case.

Check price on Amazon → (paid link)

Next: understand the wiring question in can you install a smart thermostat yourself, check the payback in how much a smart thermostat saves per year, weigh the tiers in smart vs programmable thermostats, or start from the heating and cooling hub.

Straight Answers

Frequently Asked

Does the Amazon Smart Thermostat need a C wire?

Yes, and this is the single most important thing to check before you order. The standard listing ships without an adapter and the thermostat will not power up on a system with no common wire. Amazon sells a separate bundle that includes a C-wire adapter, and that is the version to buy if your wall has only four wires or fewer. Turn the power off at the breaker, pull the faceplate off your existing thermostat, and look for a wire in the terminal marked C. A large share of the one-star reviews are from people who did not do that first.

Can you use the Amazon Smart Thermostat without Alexa?

You can run it as a plain programmable thermostat from the wall, but you cannot set up or schedule it without the Alexa app and an Amazon account. There is no separate thermostat app and no web dashboard. Scheduling, remote control, Hunches and temperature history all live inside Alexa. If you are unwilling to have an Amazon account or the app on your phone, this is the wrong thermostat and the Sensi or ecobee models are the better fit.

Does the Amazon Smart Thermostat work with Google Home or Apple HomeKit?

No. It is an Alexa-only device. There is no HomeKit support, no Google Assistant support and no SmartThings integration. Owners in mixed-ecosystem households consistently list this as the reason they returned it. If you run Google Home, the Nest Thermostat is the direct equivalent at a similar price point, and if you run HomeKit the Sensi ST55 and the ecobee models both support it.

Does it support remote room sensors?

No. There is no remote sensor accessory and no occupancy sensing beyond what Alexa infers from your other devices. The thermostat regulates the air where it is mounted, which is usually a hallway. If your house has a permanently cold bedroom or a hot upstairs, this thermostat cannot fix it — you want an ecobee with SmartSensors instead, because that is the only mainstream platform that lets a remote room drive the system.

How much can the Amazon Smart Thermostat save?

Amazon cites ENERGY STAR figures of around 8 percent on heating and cooling costs, which is consistent with independent estimates for scheduled setbacks generally. The important caveat is that the saving comes from the setbacks, not the brand — if you already run a disciplined schedule on a basic programmable thermostat, expect little or no change. Where it earns its 80 dollars is in a house that has been sitting at one temperature all day. Many utilities also offer rebates on ENERGY STAR thermostats, which can cut the effective price to almost nothing.