Thermostats · Head to head

Ecobee Smart Thermostat Premium vs Honeywell Home T9 Smart Thermostat

Full Smart Thermostats comparison in 2026

Updated October 2026
Data from the official Ecobee and Honeywell Home sites.
2026 verdict
Both fix a cold bedroom with a sensor in the box, so for a home where stale air matters as much as heat, the Ecobee Smart Thermostat Premium is the pick over the Honeywell Home T9 Smart Thermostat.
Ecobee Smart Thermostat Premium
Winner
Ecobee Smart Thermostat Premium
$244.98$259.996% OFF
Buy on Amazon USA
The Ecobee adds CO2 and VOC sensing with air quality alerts, a color touchscreen, 5 GHz Wi-Fi with Bluetooth, a trim plate and a three year warranty against two. The Honeywell Home T9 Smart Thermostat answers with filter and maintenance reminders and Smart Room Sensors that reach up to 200 ft. Both detect occupancy, read humidity, have a speaker and work with Apple HomeKit, Google Home, Alexa, SmartThings and Home Assistant, and neither supports Matter. Choose the Ecobee Smart Thermostat Premium for air quality and the longer warranty, and the T9 if maintenance reminders or a Honeywell wall plate swap matter more.
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FeatureEcobee Smart Thermostat PremiumHoneywell Home T9 Smart ThermostatWinner
Warranty3 years2 yearsEcobee Smart Thermostat Premium
Included accessoriesTrim Plate, Temperature SensorTemperature SensorEcobee Smart Thermostat Premium
Connectivity2.4 GHz WiFi, 5 GHz WiFi, Bluetooth2.4 GHz WiFiEcobee Smart Thermostat Premium
SensorsProximity / Motion, Occupancy, Temperature, Humidity, TVOC, CO₂Proximity / Motion, Occupancy, Temperature, HumidityEcobee Smart Thermostat Premium
AlertsTemperature Alerts, Air Quality Alerts, Fire Alerts, Intrude AlertsTemperature AlertsEcobee Smart Thermostat Premium
System Health MonitorNOYESHoneywell Home T9 Smart Thermostat
SpeakerYESNOEcobee Smart Thermostat Premium
Rating4.34.3Tie
IntegrationsGoogle Home, Alexa, Apple HomeKit, Samsung SmartThings, Home Assistant, External Temperature SensorsGoogle Home, Alexa, Apple HomeKit, Samsung SmartThings, Home Assistant, External Temperature SensorsTie
ScreenYESYESTie
Energy SavingsYESYESTie
Voice ControlYESYESTie

What the differences mean

Air quality

The Ecobee Smart Thermostat Premium measures CO2 and VOCs and alerts you when indoor air turns stale. The Honeywell Home T9 Smart Thermostat senses temperature, humidity and occupancy but not air quality.

Maintenance reminders

The T9 reminds you when the filter and other maintenance are due. The Ecobee has no system health monitor.

Screen

Both are touchscreens. The Ecobee's is a 4 inch color display showing weather; the catalog does not list the T9's as a color screen.

Wi-Fi

The Ecobee joins 2.4 or 5 GHz networks and has Bluetooth. The T9 is 2.4 GHz only, and one of its owners had trouble with a mesh router.

Warranty

Three years on the Ecobee Smart Thermostat Premium, two years on the Honeywell Home T9 Smart Thermostat.

Which one to buy if

What owners say

Owners of both thermostats say the included room sensor is the reason to buy: each group describes the system correctly heating the room people are in rather than the hallway. Ecobee Smart Thermostat Premium owners add learned schedules that cut cycling, a screen that wakes on approach and Alexa or Siri on the unit, and complain about harder installs in older homes, readings skewed by a nearby vent, app glitches and slow support. Honeywell Home T9 Smart Thermostat owners add HomeKit pairing, the C wire adapter in the box and a unit that often fits an older Honeywell wall plate, and complain about the Resideo app, a Wi-Fi adjustment that sets a permanent hold and sensor batteries that can run down quickly.

Frequently Asked Questions

Ecobee vs Honeywell T9: which is better, the Ecobee Smart Thermostat Premium or the Honeywell Home T9 Smart Thermostat?

The Ecobee Smart Thermostat Premium. Both include a room sensor and detect occupancy, but the Ecobee adds air quality sensing, dual band Wi-Fi, a trim plate and a three year warranty. The Honeywell Home T9 Smart Thermostat adds maintenance reminders.

What is the biggest difference between the Ecobee Smart Thermostat Premium and the Honeywell Home T9 Smart Thermostat?

Air quality. The Ecobee Smart Thermostat Premium measures CO2 and VOCs and sends air quality alerts, while the Honeywell Home T9 Smart Thermostat does not.

Do both come with a room sensor?

Yes. The Ecobee Smart Thermostat Premium includes a SmartSensor and the Honeywell Home T9 Smart Thermostat includes one Smart Room Sensor, and both support adding more.

Do they work with Apple Home?

Yes. The Ecobee Smart Thermostat Premium and the Honeywell Home T9 Smart Thermostat both work with Apple HomeKit, Google Home, Alexa, SmartThings and Home Assistant. Neither supports Matter.

Who should buy the Ecobee Smart Thermostat Premium?

Homes that want air quality monitoring alongside multi-room heating, buyers with 5 GHz networks, and anyone who values a three year warranty.

Who should buy the Honeywell Home T9 Smart Thermostat?

Owners replacing an older Honeywell who want an included room sensor, filter reminders and HomeKit support.

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