You’ve to check compatibility of a thermostat with your homes HVAC system, before you buy the thermostat. We believe checking thermostat compatibility is very important for anyone buying a new thermostat or replacing an old model. If you don’t check thermostat compatibility, you might end up purchasing the wrong model. We’ve created a comprehensive thermostat compatibility guide covering almost all the current best selling thermostat models.

Compatibility Guide for Smart Thermostats

Let’s begin with smart thermostats as they’re the best selling models currently. Most people prefer to use smart thermostats these days as they are self learning, saves energy and can be controlled from anywhere via internet.

Ecobee 4 & Ecobee 3 Lite

We’ve published a dedicated review of Ecobee 4 & Ecobee 3 Lite covering all aspects including compatibility. If you’re considering Ecobee thermostat, please go through our guide and get informed.

Ecobee Thermostat Compatibility

The table below explains compatibility of Ecobee 4 and Ecobee 3 Lite with a wide variety of heating/cooling systems out there.

Nest 3rd Gen & Nest E

Nest thermostats are compatible with a wide range of HVAC systems, especially the Nest 3rd Generation Learning Thermostat. The table below explains Nest thermostat compatibility (Nest 3rd Gen and Nest E) with different types of heating/cooling systems. We’ve covered Nest 3rd Gen and Nest E thermostats in our complete review and comparison guide.

Emerson Sensi ST75

We’ve covered Emerson Sensi ST75 in a detailed review. The table below explains compatibility of Emerson Sensi ST75 with different types of HVAC systems.

Honeywell RTH9585WF

This model from Honeywell, RTH9585WF is one of the best selling WiFi thermostat models out there. We’ve listed the complete compatibility of Honeywell RTH9585 thermostat model in the table below.

Compatibility for Line Voltage Thermostats

Thermostats are basically for two types of systems – low voltage and line voltage. Thermostats designed for line voltage systems (like baseboard heater, convectors etc) are not compatible to be used with low voltage systems (like central furnace, heat pumps, boilers etc). Similarly, thermostats designed for low voltage systems can not be used with line voltage systems as well. You’ve to identify your home heating system first (if it’s a low voltage or line voltage system) before choosing your thermostat.

In USA, 90% of homes are using low voltage systems like a central furnace or a heat pump or a boiler as their heating/cooling system. Only about 10% of homes are using line voltage systems like a baseboard heater or a forced fan heater or a convector or a radiant ceiling heater.

MySa – Smart Line Voltage Thermostat

MySa is a smart line voltage thermostat compatible with all commonly used high voltage systems. Complete compatibility is explained in the table below.

Winding up!

We’ve covered almost all best selling thermostat models in our comprehensive thermostat compatibility guide. We will be adding newer models in coming days. If we’ve missed an important model, please comment here. We shall add them shortly.



  1. Have a heat Boiler and trying to use a T5 Smart Thermostat. It is a Utica heat boiler. How would I be able to wire this with only two wires coming from the boiler — Red and White. I also have a 24V AC local power supply to power up the T5 unit. Let me know. Thanks.

    • Mathew Kevin Reply

      In this case, you just need to connect the ‘R’ and ‘W’ terminals of the thermostats and leave all other terminals intact without making any connection.

      For example, the Nest 3rd Gen thermostat has 10 terminals, say Rh, Rc, W1,W2(aux) Y1, Y2, O/B, G, C, etc. You just need to connect ‘red’ wire from furnace/boiler to Rh and ‘white’ wire to W1. These 2 connections will set the Nest thermostat as a ‘smart 2 wire thermostat’ taking care of your home heating ‘smartly’.

  2. Can an ecobee or Nest thermostat handle an American Standard variable-speed heat pump system?

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