ecobee Smart Thermostat Premium Review: The $259.99 Thermostat for the Room That Runs Cold

ecobee Smart Thermostat Premium in black showing 72 degrees, 40 percent humidity and a Clean air reading

Product image supplied by the brand

In this guide

THE SHORT VERSION

ecobee's Smart Thermostat Premium is the $259.99 top of the company's current US line, above the $199.99 Smart Thermostat Enhanced and the $139.99 Smart Thermostat Essential. On 2026-10-10 the ecobee product page showed it in stock with an active Add to bag, shipping at no charge, and no discontinuation or previous-model marker. The package carries the thermostat, a mounting plate, a trim plate, wire labels, screws and drywall anchors, a Power Extender Kit, and one SmartSensor with a detachable stand and an adhesive wall mount.

The purchase decision usually starts with a different price: $129.99 for Google's Nest Thermostat, which Google's own comparison says is not compatible with a Nest Temperature Sensor at all. A room that runs cold can be answered with a second thermostat, with a sensing change, or with duct work, and only one of those is what this device sells. The four extras over the Nest — the included sensor, the air-quality reading, the security hub, and the built-in Alexa — divide cleanly into hardware and a monthly plan.

Our verdict

Buy the $259.99 Smart Thermostat Premium when one room's temperature should drive the cycle and your system is 24 VAC with a C wire or room for the included Power Extender Kit. Its advertised security features cost $5 a month.

A good fit for: A single-zone house where one or two rooms run hot or cold against the hall, on a 24 VAC furnace or heat pump with a C wire or the included Power Extender Kit.
We would skip it if: A house with even temperatures, a 120/240 V electric baseboard or millivolt system, or a two-wire heat-only control with no spare conductor; also anyone who will not pay $5 a month for security features.

Reasons to consider it

One SmartSensor is in the box and its reading is averaged into whichever Comfort Settings you tick, so a bedroom can end a heating call instead of the hallway; ecobee sells extra sensors only as a $99.99 two-pack.
The box also includes the mounting plate, trim plate, wire labels, screws and drywall anchors, and a Power Extender Kit that ecobee sells separately for $24.99, so a missing C wire does not add hardware cost on this model.
Warranty runs for three years with limits, five when a pro installs it, against one year on Google's $129.99 Nest Thermostat, and the thermostat is wired 24 VAC with no batteries to replace.

The compromises

Auto-siren, arm and disarm assistance, guest codes, smoke-alarm listening and 30-day event history sit in Smart Security Plus at $5 a month or $50 a year; the free Core tier keeps alerts, motion detection, freeze protection and live view.
Air quality is a relative sensor reading volatile organic compounds and estimating CO2 from them, with no PM2.5 measurement; it can alert, remind you about the filter, and run a compatible ventilator for 20 minutes on a beta feature.
The Power Extender Kit cannot be used on heat-only or dual-transformer systems, so a boiler or a two-wire heat-only thermostat needs a C wire, a new conductor, or third-party parts before the features matter.

What we have not verified: ecobee's 26% and $284 saving figures rest on its own April 2021 analysis of a $1,091 average heating-and-cooling spend, while the ecobee-published Demand Side Analytics report measures eco+ adding about 5% to 6% over thermostat-only use; a house already running setbacks should read both as ceilings. Whether this generation ever adds Matter certification is also open, since ecobee's current specifications cover Apple Home, Alexa, Google Assistant and SmartThings but no Matter.

The things in this guide

A closer look at the products, who they may suit, and what to check before buying.

The thermostat to buy when one room should set the temperature

ecobee Smart Thermostat Premium

$259.99 on 2026-10-10 buys a wired 24 VAC thermostat with one SmartSensor in the box, per-comfort-setting sensor averaging, Follow Me, a VOC-based air-quality reading, Apple Home and Alexa support, and a limited three-year warranty.

Before you buy: The advertised security features need Smart Security Plus at $5 a month, the air-quality sensor is relative rather than lab-grade and measures no particulates, the Power Extender Kit will not rescue a heat-only or dual-transformer system, and ecobee lists no Matter certification.

$259.99 at ecobee

Price checked October 10, 2026. Retailer prices can change.

What $259.99 puts on the wall, and what a second room adds

One SmartSensor ships with the Premium — the same sensor ecobee sells on its own only as a two-pack for $99.99, so about $50 apiece. That is what lets a two-room temperature problem be answered without buying a second thermostat and its wiring. Each ecobee account takes up to 32 sensors, they communicate on 915 MHz rather than Wi-Fi, and ecobee places them up to 60 feet from the thermostat. A CR2477 cell is rated at up to five years, so the ongoing expense is a coin cell rather than a subscription.

The rest of the box is installation hardware, not accessories. Besides the thermostat and its mounting plate there is a trim plate, wire labels, screws and drywall anchors, and a Power Extender Kit. ecobee sells that PEK separately for $24.99 and includes it with every current model except the Essential and Lite, so a house with no C wire does not pay again here.

The sensor changes the number the thermostat averages

Participation is the mechanism that matters. For each Comfort Setting — Home, Away, Sleep, or one you build — you tick which sensors count, and the thermostat averages only those readings. The built-in sensor can be left out, so a bedroom sensor can drive the overnight setpoint while the hallway is ignored. A sensor entering or leaving the average is phased in over 30 minutes instead of stepping the temperature.

Follow Me weights the sensors in rooms with recent activity, but only among the sensors already ticked for the active Comfort Setting, so it refines the average rather than adding rooms on its own. The practical result is that a SmartSensor can be the input that ends a heating call, not just a remote display. Google's comparison table puts the $129.99 Nest Thermostat on the far side of that line: it is not compatible with a Nest Temperature Sensor at all.

Air quality here means VOCs and an estimate of CO2

ecobee's support documentation is narrower than the marketing. The Premium measures volatile organic compounds with a relative sensor, then estimates CO2 from the correlation between VOCs and CO2 in exhaled breath; it does not measure CO2 directly and describes no particulate counter for PM2.5. Readings land in Poor, Fair or Clean, with VOC and CO2 each scored Low, Moderate or High against the range the sensor has seen over the past four days.

Calibration typically finishes within an hour and can take up to eight. With a compatible ventilator connected, a poor reading can start it for 20 minutes — a feature ecobee labels beta — while the ordinary response is an app alert and advice to ventilate. Filter-change reminders are the other concrete output. The useful signal is a change after cooking, cleaning or a sealed-up weekend, not a number to compare between two homes.

The security hub, and the $5 line between free and useful

The radar in the thermostat does double as a motion and occupancy sensor, and ecobee's free Core plan covers motion detection, door and window alerts from contact sensors, a door chime, an activity feed, freeze protection and live view. The features that make it a security system — the automatic siren, arm and disarm assistance, guest codes, smoke-alarm listening and 30-day event history — sit one tier up in Smart Security Plus at $5 a month or $50 a year.

Advanced at $10 a month lifts the camera cap, and 24/7 professional monitoring is a separate add-on: $5 monthly for smoke-alarm dispatch or $10 for break-ins and smoke. Door and window contact sensors list at $59.99 and showed $49.99 on 2026-10-10. None of it is needed for scheduling, eco+, Home Energy Reports or the sensor averaging. Google's Nest Thermostat has no comparable paid tier since it lacks those features.

24 VAC first: the wiring decides before the features do

The Premium is a 24 VAC thermostat powered through C and Rc, with no batteries. ecobee rates it for conventional furnaces and air conditioners at two heating and two cooling stages, heat pumps at two heating stages plus two stages of auxiliary heat, boilers, PTACs and fan coil units with up to three fan speeds, plus one one-wire or one two-wire accessory for a humidifier, dehumidifier, HRV or ERV, with a second accessory only through a Pro setup. Zone boards need no special configuration.

The included Power Extender Kit covers a missing C wire in most four-wire installs, but it cannot be used on heat-only or dual-transformer systems; a boiler needs a C wire or a third-party part, and a two-wire heat-only thermostat needs a new conductor, an isolation relay or a common maker. High-voltage baseboard and electric furnaces (120 or 240 V, L1/L2), millivolt wall heaters, proprietary and solid-fuel systems, equipment with three or more stages, and inverter or VRF mini-splits are not directly compatible.

Enhanced at $199.99, Essential at $139.99, and a three-year warranty

Dropping to the $199.99 Smart Thermostat Enhanced saves $60 and keeps the radar occupancy sensor, the 4-inch 540-by-540 screen and the Power Extender Kit, but its specifications name temperature, humidity, radar occupancy and proximity sensors with no air-quality sensor, and its box holds no SmartSensor. It also controls a single accessory where the Premium supports two through a Pro setup, and caps heat pumps at two stages of heat with one stage of auxiliary. The $139.99 Essential gives up the radar too and sells the PEK and trim kit separately.

All current ecobee thermostats carry a limited three-year warranty, extended to five years when a professional installs them, and the SmartSensor also carries three years. Built-in voice is Premium-only: Alexa runs on the device, while Siri requires a paired HomePod or HomePod mini. ecobee's product page names Apple Home, Alexa, Google Assistant and SmartThings but does not list Matter, while Google's Nest Thermostat is Matter certified.

Where the 26% and the $284 actually come from

The savings headline comes with its own footnote. ecobee's up to 26% and up to $284 a year trace to an internal analysis conducted in April 2021, built on an average North American heating-and-cooling spend of $1,091 multiplied by 26%, and the page notes that annual savings will vary with energy use and location. A house that already sets back its thermostat starts from a different baseline than the constant-72-degree hold ecobee uses for comparison.

The separate evidence is vendor-funded as well. Demand Side Analytics, in a report ecobee published, found eco+ users saving 5% more energy than thermostat-only users in summer 2020, in line with 6% the year before, and time-of-use customers cutting 7% to 23% of cooling costs. Those percentages describe an added software layer over an existing smart thermostat, not a guarantee from buying the hardware.

When the $129.99 Nest Thermostat is enough

Google's entry model lists at $129.99 and the Google Store showed $99.99 against a crossed-out $129.99 on 2026-10-10. It is Matter certified, takes power from HVAC wiring with two AAA backups, and carries a one-year warranty against ecobee's three. Its limits are the mirror image of the Premium's features: no remote temperature sensor, no air-quality reading, no built-in voice assistant, and no security hub to subscribe to.

So the Nest is the right pick when the hallway or living-room reading is already the one you care about, when nobody edits the weekly schedule from the wall, and when the imbalance is airflow rather than sensing — a remote sensor changes which room the thermostat believes, not how much air reaches that room. If the schedule is set once in the app and the hallway reading is fair, the $99.99 sale price saves $160, and the remote sensor at the center of the Premium's case would have nothing to correct.

How we put this together

Built from the product pages and listings below, without test scores or results we have not measured. Specifications and prices change, so check the original page for the exact model, current price, delivery, and returns.

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