Best Smart Thermostats of 2026

Line-voltage heat is the awkward corner of this market. Baseboard heaters and fan-forced convectors run on 120 or 240 volts, and a 24V thermostat can't control them at all — which is why so many rooms are still stuck with a dial on the wall. The Mysa is built for that circuit, up to 3800 watts, and it brings a baseboard room into the same app as everything else in the house.

Installation is the part to understand before you order. The Mysa needs a neutral or a second live wire in the wall box, and older baseboard circuits don't always have one. Look at the wires first, and stop if there are only two — this isn't a circuit to improvise on, and the breaker stays off until the faceplate is back on.

Once it's running, it does what a baseboard room actually needs: schedules, geofencing, a humidity reading, energy insights, and HomeKit, Alexa and Google support with no subscription behind any of it. The 3.5-inch display is small, but the touch feedback is audible, so you know a press registered without staring at it.

The practical limit is arithmetic — one unit per heating circuit, so a house with four baseboard zones needs four of these, and that adds up even though each one is sensible on its own. For a cabin, a basement or a converted porch, a single unit is an easy yes.

The most important thing in the ecobee Enhanced's box is a small plastic adapter. The Power Extender Kit lets the thermostat run on a system with no C-wire at the wall, and that's why it's our top pick: plenty of houses never had a fifth wire pulled to the hallway, and this solves the problem in the box instead of with an electrician's visit. A trim plate comes with it too, which covers the paint line left by a larger old unit.

Installation runs through the app, which has you label and photograph the wires before you disconnect anything. That photo is the difference between a calm half hour and a confusing one. ecobee rates the Enhanced for about 90% of 24V systems and publishes a compatibility checker; run it before you order, because heat pumps are where this model draws the most disagreement.

Day to day, the occupancy sensing is what we noticed. The house drifts while nobody's home and comes back to temperature before you arrive, and after a week you stop managing it. The 4-inch LCD is plain next to the Nest's polished circle, and that's fine — this is a thermostat you mostly operate from your phone.

Auxiliary heat is the one behavior worth watching. On some systems it comes on below roughly 35°F sooner than the outdoor temperature suggests, which on a heat pump in a cold climate is worth a month of attention before you trust the savings claim. Some units also fail outright, which is the pattern to weigh against the three-year warranty.

The Sensi ST55 is the cheapest way into a genuinely smart thermostat, and it doesn't announce the fact. It's a white rectangle with physical buttons, sized to sit in the same footprint as the thermostat it replaces, so there's no patching and no painting. An upgrade that doesn't turn into a drywall project is worth something.

It also runs without a C-wire in most homes, which at this end of the range is the unusual part. Installation is a screwdriver job with a built-in level on the backplate and step-by-step guidance in the app, and we liked how little ceremony there is: no account juggling, no hub, no subscription.

What you get is deliberately plain — scheduling, remote access, usage reports, filter reminders, and Alexa, Google Assistant, Apple HomeKit and SmartThings support. What you don't get is a touchscreen or any learning. We ended up preferring the buttons: a guest can walk up and change the temperature without a tutorial.

The longer-term risk is the part we can't wave away. These Sensi units are the least reassuring in this group over a couple of years, with failures that arrive well before a thermostat should. The three-year warranty covers you, but a warranty doesn't heat the house in February.

A 4.5-inch color touchscreen showing indoor temperature, outdoor temperature and humidity is the whole argument for the Honeywell 9000. It's the one here that reads like a small control panel rather than a puck, and everything — schedule, fan, hold — lives on the glass instead of three menus into an app.

The screen is customizable, down to background color and which readings get displayed, and the brightness adjusts if the hallway version is glaring at two in the morning. Alerts and reminders surface both on the display and in the app, which sounds minor until a filter reminder arrives before the system starts straining.

Underneath it's a conventional seven-day programmable thermostat with the Total Connect Comfort app and Alexa, and we think the hardware is the most legible wall experience in this set — a claim with one big caveat attached. It needs a C-wire, and Honeywell lists it as unsuitable for dual-fuel heat pumps without a fossil kit. Read that line before you buy, because it's an exclusion the maker states outright rather than one you discover mid-install.

If your system qualifies, you get a thermostat a whole household can run without a phone: touch a day, drag a setpoint, done. The app is the oldest-feeling interface in this group, and the value question is real when the Sensi does the same core job — but the Sensi doesn't look like this on the wall.

Polished gold, a display 60% larger than the outgoing model, and a bezel that picks up the room: the fourth-generation Nest Learning Thermostat is the only one here people will comment on. Whether that's worth paying for depends entirely on where it hangs. A wall you pass twenty times a day, yes. The back of a closet door, no.

The bigger screen does work. Dynamic Farsight shows the time, weather or temperature from across the room, so you stop walking over to squint at it, and the body is aluminum rather than plastic. The box also includes a Nest Temperature Sensor, which solves the classic problem: the hallway where the thermostat lives is never the room you're trying to keep comfortable.

It's Matter certified and speaks to Alexa, Siri and Google Assistant, which is broader voice support than most of this set. What it won't do is talk to the old Nest app — everything runs through Google Home now, and if you're upgrading from an earlier Nest expecting the same app, that's the surprise waiting for you.

Learning is the headline, and it's the part we're least convinced by. The occupancy behavior and the included sensor are what actually change how a room feels; the algorithm noticing your weeknight habits is a slower, subtler thing. Watch the accuracy too — these can read a couple of degrees off, so put the sensor where you sit rather than trusting the number on the wall.

The Sensi Touch ST75 is the ST55 with a 4.3-inch color touchscreen and a C-wire requirement, and that trade is the entire decision. Appearance is what this model does best in the set: the black finish and backlit color display look deliberate on a painted wall in a way the button model doesn't, and the temperature reads from across the room.

Everything else is the family recipe: the same app, the same Alexa, Google Assistant, Apple HomeKit and SmartThings support, the same guided install with illuminated terminals, and a three-year warranty. The illuminated terminals matter more than they sound — wiring a thermostat in a dim hallway is where most do-it-yourself installs go sideways.

The catch is the C-wire. The ST75 requires one and doesn't adapt around its absence, so a four-wire wall turns this into an electrician job and makes the cheaper ST55 the better buy. With five wires, you're paying more for a nicer wall interface over the same software, and that's a fair trade for a hallway you look at every day.

If your system is more complicated than a single-stage furnace, this is the one to look at: the Vision Pro 8000 handles up to three stages of heat and two of cooling, more than anything else here. It's also the most installer-shaped product in the set — a plain square face, a modest screen, and a five-year manufacturer warranty that's conditional on proof of professional installation.

That condition is the thing to read twice. Do it yourself and you're relying on the seller's one-year coverage instead of Honeywell's five, on a unit that assumes someone who does this weekly. We think that math is straightforward: if you're already paying someone to commission a multi-stage system, the long warranty is free; if you're not, buy one of the simpler units and keep the money.

What the extra complexity buys is control — remote access from the phone, Alexa, humidity and dehumidification settings, and air circulation, on a device that keeps running its program locally when the network doesn't. Reliability is among the steadier results in this group, and the plain face is the reason it disappears into a hallway instead of starting a conversation.