In the USA, about 90% of homes are powered by a central heating/cooling system like a central furnace or a boiler or a heat pump based system. We write about boiler thermostats in this guide, which are thermostats for controlling central boiler units. A boiler is basically a specially designed water heater – which distributes heat through hot water, while systems like a central furnace distribute heat through the warm air. Water is heated in a special chamber of the boiler (which is usually powered by gas or fuel oil) and is then distributed to different rooms of the home via radiators or other heat distribution systems installed. A boiler thermostat helps in controlling the boiler operation, thus maintaining a proper set temperature inside the home.

Boiler Heating System

As I noted above, there are different types of boiler systems like gas-fired boiler, steam boiler, and fuel oil-based boiler. Out of these 3 types, gas-fired boiler is the most common one in USA, just like the central furnace-based heating systems. You may find steam boilers in some older home constructions, but they are being replaced eventually. Fuel oil based boilers are not used in US homes due to many reasons like foul smell, and efficiency problems. All thermostat models reviewed below are suited to use as a gas boiler thermostat – be it a smart thermostat or a WiFi/Wireless boiler thermostat model or just a normal programmable thermostat variant.

We are here to help you learn more about boiler thermostat models, to find the right one that best fits your boiler heating system.

Smart Boiler Thermostats

“Smart Thermostats” are technologically superior, modern, internet connected thermostats which can save energy like no other thermostat. A smart thermostat can save energy in the range of 10% to a max of 23% (under ideal conditions) annually. Apart from energy savings, smart thermostats are built with high end features like control from anywhere using smartphones, self-learning (auto-scheduling and auto programming), voice control, geo fencing (turning your boiler ON/OFF based on homeowner’s location). Let’s see the best smart boiler thermostats available.

#1 Ecobee 4 & Ecobee 3 Lite

Out of the 2 models, Ecobee 4 – is the full featured model with high-end features like built in Amazon Alexa (for voice control) , self learning (auto programming/scheduling), geo-fencing, smart phone-based control via internet, and above all energy savings upto 23% (as claimed by Ecobee company). Ecobee 4 also comes with an extra room sensor to setup zoned heating/cooling and manage any hot/cold spots in your home.

You may read our full review of Ecobee Smart Thermostat – comparing Ecobee 4 vs Ecobee 3 Lite. You will get to know complete features and compatibility with your HVAC system.

Ecobee 3 Lite – is the budget model, which is basically a trimmed down version of Ecobee 4. The budget model has all important features of Ecobee 4, except that it has no built-in Alexa (you’ve to purchase Alexa device separately to enable voice control in Ecobee 3 Lite), and there is no extra room sensor provided (you can buy room sensors separately). Finally, take note that the full featured model Ecobee 4 is compatible with more types of heating/cooling (HVAC) systems. Ecobee 3 Lite may not be compatible with central heating systems having 3 or 4 stages. Also, Ecobee 3 Lite doesn’t support any accessories like humidifiers or dehumidifiers.

Note: We’ve created a guide featuring compatibility of different thermostat models – where we detail compatibility with different stages, accessories, aux systems etc.

#2 Nest 3rd Gen and Nest E

Nest 3rd Gen thermostat

Nest E thermostat

Our #2 choice is Nest 3rd Gen and Nest E. In our opinion, Nest smart thermostats are equally good as Ecobee models. They both can be #1 choice alike. But we chose Ecobee as #1 for the extra room sensor (that comes with Ecobee 4) and the alternative option for a C wire/common wire (if you don’t have c-wire, Ecobee provides a PEN – power extender kit which can be used to solve the C – wire requirement).  Just like Ecobee, Nest has two models namely Nest 3rd Gen and Nest E. The full featured model Nest 3rd Gen thermostat has more features, higher compatibility and better build quality compared to the budget model Nest E. Nest thermostats also goes well as a gas boiler thermostat, and can be used perfectly for your gas boilers.

Nest 3rd Gen – “Learning Thermostat” – as Nest calls it officially is a self learning thermostat that programs itself by learning lifestyle patterns of homeowners. It also has advanced features like “geo-fencing”, internet connected control using smartphones, vacation schedules, energy reports, and many other features. The key highlight is “energy savings” – where Nest claims upto 13% of annual savings with their thermostats.

If you’re interested in Nest thermostat, you should read our review of Nest 3rd Gen vs Nest E – where we compare both models with features and compatibility.

Nest E – the budget model thermostat is a trimmed-down version of full featured model. The primary difference being lesser compatibility (Nest E is not compatible beyond 2H/1C – 2 stages of heating and 1 stage of cooling) and build quality (Nest E is built of plastic materials). Apart from this difference, all high end features of a smart thermostat like “self learning”, controlling via smartphones, energy savings, geo-fencing and other features are common for both Nest models.

Nest – Compatibility as a boiler thermostat

Nest 3rd Gen is compatible upto 2H/2C – Two stages of heating and Two stages of cooling for boilers. As a boiler thermostat, Nest 3rd Gen model supports “dual transformer configuration” – where there is more than one R wire.

Nest E is compatible only up to 2H/1C – Two stages if heating and One stage if cooling as a boiler thermostat. Nest E does not support dual transformer configuration.

You may read through our thermostat compatibility checking guide to learn more about Nest Thermostat compatibility with different systems.

Wireless/WiFi – Boiler Thermostats

As we’ve seen, “smart boiler thermostats” come packed with a lot of high-end features like “self learning”, geo-fencing, high energy savings, WiFi and internet-based control, and more. All these features are really useful but they come with a high price tag as well. If you’re looking for an affordable modern thermostat, then WiFi enabled boiler thermostats are a good choice. Just like smart thermostats for boilers, these WiFi-enabled models are good to use as a gas boiler thermostat or as an oil boiler thermostat.

These models will have all those “essential new generation features” like voice control, WiFi connectivity, touch screen, smart home hub integrations, programming/scheduling via mobile apps, and a lot of other useful features, except high-end ones like “self-learning” or “auto programming”. The energy-saving rate of wireless thermostats wouldn’t be as high as a smart thermostat but you can expect anything in between 5% and 10%. The key highlight is affordable price compared to a smart thermostat model.

#3 Honeywell RTH9585WF – WiFi Boiler Thermostat

RTH9585WF Thermostat

When it comes to WiFi thermostat models, “Honeywell RTH9585WF” is the #1 choice anyone should consider. This model from Honeywell is an upgraded version of its best-seller – “Honeywell RTH9580WF” – which once ruled as the #1 WiFi thermostat for boilers or other central heating systems.

Honeywell RTH9585WF – is a WiFi enabled, programmable thermostat with a color touch screen. One highlight of this model is “different color choices ” available on the touchscreen interface, which you can select to match your room interiors. The bigger display & touch screen interface makes it appealing to people who don’t prefer the “minimal display size” of Nest & Ecobee thermostat models.

The key highlight of the model is WiFi based control over the internet. You can control this thermostat via the internet from anywhere in the world using the mobile app (provided by Honeywell). You can set new schedules or change the existing ones, turn ON/OFF, read current room temperature, etc from anywhere. Apart from WiFi-based control, this model also supports voice control via Amazon Alexa or other smart home hubs like Apple Homekit, Google Home or another supported smart home device.

Boiler Compatibility

Honeywell RTH9585WF supports boilers up to 2H/2C – that is 2 stages of heating and 2 stages of cooling. This model supports boilers with gas, oil, or electricity as a fuel source. Take note that accessories (like humidifiers, or ventilators) are not supported. Also, keep in mind, this model requires a “C-wire” in your home wiring setup.

#4 Emerson Sensi ST75

The next best choice in WiFi-enabled boiler thermostat models is “Emerson Sensi ST75” – which is a wireless/WiFi thermostat from home automation giant Emerson. We’ve reviewed Emerson Sensi ST75 in detail, and we believe this thermostat is a great choice for any of the common boiler types used in US households.


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