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The invention of smart thermostats changes the way of controlling the temperature inside the house. Still, there are many limitations like most advanced. Big players are only manufacturing smart thermostats for low voltage systems, so those are not compatible with high voltage heaters, baseboard heaters, convectors, and forced fan heaters. A separate line voltage thermostat is required to control these high voltage systems that give birth to a line voltage smart thermostat idea.

A line voltage smart thermostat can regulate the heating and cooling systems that run on the direct electricity of 240V of 120V and stay connected with the mobile app through Wifi connectivity. Electric baseboard heater is a known example that is commonly used in the USA.

What is Line Voltage Thermostat?

If you ever experience this thermostat, then you know well that thick wires come out from the base of a high voltage thermostat because it is a device that runs on direct line voltage and used to regulate the heating system like baseboard heaters. It is also known as a two-wire thermostat.

It is simple to install. In fact, its installed ins series with the heating system. And its simple functionality ON/OFF the power to heating device intermittently. The thermostat can detect the temperature, and when the required temperature is reached, it cut the power to the heater, it’s simple. When the temperature dropped again through the electricity, so the heater starts working again. Honeywell multi-zone thermostat is the best one when you have to select a low voltage smart thermostat.

Before you buy any thermostat for your heater, you need to check the compatibility with your device. A high voltage smart thermostat usually used for the following equipment:

  • Baseboard heaters (or any resistance heaters)
  • Forced Fan Heaters & Convectors
  • Radiant Ceiling Heaters

If you are sure about your heating system and know well what type of thermostat you need, you can surely pick one, or you may check the base of your existing thermostat to figure out what type of thermostat it is. If you found more than two wire coming ours from your thermostat, that means you are not using a line voltage system.

Smart thermostats are getting attraction day after day, but a minimal choice is available for line voltage thermostats. Here in this article, I list the three best smart line voltage thermostats, and no other options are available in the market.

You may also like our recent blog posts on the Honeywell Multi Zone Thermostat Review and 3 Best Ovens With Slide Away Doors available on the separate page.

Mysa Smart Thermostat for Electric Baseboard Heaters

line voltage smart thermostat

  • High line voltage compatible 
  • Easy to install 
  • Wifi connectivity 
  • IOS and Andriod App

Mysa Smart Thermostat for Electric Baseboard Heaters comes as a first choice when controlling the baseboard heaters. Its high voltage compatibility provides remote access through Wifi connectivity. When it’s connected with the Wifi, it can be controlled from anywhere, and its app, either ios or Andriod, provide full control over the thermostat. Like from the app, users can make a schedule, view the current setting, and set the temperature.

Full control means users do not have to go near the thermostat; all configurations are accessible from the remote app.

It’s easy to install and hardly will take 20 minutes to install. It’s equipped with many amazing features like its vacation mode, suspend all operations for a specific time, and an easy scheduling offer to makes a schedule with just a few touches.

Smart does not only means wifi connectivity, but it’s also compatible with Amazon Alexa, Google Home, Apple HomeKit, and IFTTT. So it’s possible to add voice control to this smart baseboard thermostat. Its connectivity is quick and stable while watching tv or during cooking. 

You can ask your intelligent voice assistant to raise the temperature or turn on a favorite mode.

It also supports geofencing, which can turn your heater on and off when you enter and leave defined radios and control are available on the mobile app. But I figure that this feature is hidden in the experimental features menu on the mobile app, so it may not be visible for everyone until one is aware of it.

The thermostat elegantly its a minimalist dot-matrix display, and capacitive touch-sensitive buttons make it a stunning and straightforward design but its app too, which is most simple and easy to operate and design while keeping the user-friendly approach in focus.

In its line, it’s the most expensive thermostat but a trustworthy option that comes as a one-time investment and can serve you for a longer period.

Shop now at Amazon

Stelpro STZ402+ ki WiFi Ready Smart Thermostat, ZigBee Ready

high voltage smart thermostat

  • Zigbee compatible
  • Can control electric baseboards and convectors up to 4000W
  • Compatible with forced fan heaters 
  • Equipped with humidity sensor

Stelpro STZ402+ ki WiFi Ready Smart Thermostat is fully compatible with the Zigbee hub, and this connectivity enables the user to get control over mobile and add many other functionalities. This smart device can control the electric baseboard heaters and convectors up to 4000W. I figure out that it is useable in most homes and a perfect smart device with a remote app. Modern thermostats cannot control the baseboard equipment. 

Having such a Wifi enabled device that effectively manages all high voltage heating solutions can be a good addition to any home.

You may not feel comfortable if you are not using the Zigbee hub because its remote connectivity depends on the Zigbee. Usually, I recommend it to those who have a good experience with the Zigbee Hub and know how it works. If you have already set up your smart home using Zigbee hub, then it’s a perfect solution for your home. A user can comfortably control the temperature of his house from a distance. 

Its made to be paired with controllers that can further enhance its functionality. You will be amazed to know that it can adjust the lighting, activation of the safety and entertainment system, temperature, and much more.

Any novice user can make a schedule as he wishes because of its straightforward and simple scheduling feature. I used this system for a long time to automate my forced air unit system, and it works amazingly, but I was not using Zigbee for other devices. 

Hence, it was a big reason to move forward and replace it with a system controlled directly through Wifi.

Shop now at Amazon

Stelpro ASMT402 Smart Home Thermostat

smart line voltage thermostat

  • Made for Baseboard, convectors, and fan heaters
  • Maestro controller and Zigbee compatible
  • Accessible and can be controlled from the mobile app
  • Energy saver 

Stelpro ASMT402 Smart Home Thermostat is an excellent energy saver. It can save up to 25% energy on heating devices that is a great feature and benefit of this thermostat. It all becomes possible with smart features and scheduling.

This device is packed with many features like its connectivity with Maestro and Zigbee hub provide remote access through the app from where you can set up schedule access reports and change the temperature and view schedules. 

Having access to the mobile app is a benefit that allows you to control your home’s temperature from any part of the world. If if you are already using any hub from the above-mentioned and set up your home already, you need to buy this thermostat. Its install and configuration will take hardly 20 minutes. Thereafter it will start working with your existing system.

It can control the heating devices that come with a maximum power of 4000 watts that really makes it viable to use with any existing system.

Shop now at Amazon


Nowadays all the applications for line voltage involve electric resistance heaters. If you have installed any of following heater type you can administer temperature with a smart line voltage thermostat, Electric Baseboard Heaters, Wall Convectors, Fan Forced Wall Convectors and any type of under floor heater.

A line voltage thermostat is a right solution for fan coil heating unit, but keep in mind it requires multi speed fan. But here the problem is only few of recent models are compatible with line voltage thermostat.

Line voltage thermostats are not compatible with the central forced air furnace systems. Your cannot use these thermostats with electric furnaces, gas furnaces, boilers and heat pumps.

The line voltage thermostat only works with the control heaters, you cannot run your cooling devise with it.

Final Thoughts

I was convinced that there is no proper smart thermostat for line voltage systems, but recently the entry of MySa fill this gap. In the USA nearly 10% of homes use line voltage heating system which earlier was using simple and programmable thermostats which do not have any connectivity.

But now there is a solution. Maybe we will see a single thermostat to deal with all low voltage and high voltage heating and cooling systems in the future.

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