10 Best Line Voltage (High Voltage) Smart Thermostats

If you're tired of wasting money on your heating bills, a line voltage (also known as a high voltage) smart thermostat may just be the solution. These thermostats enable you to regulate the heat from your electric heaters allowing you to control the temperature in your home remotely.

Different models support different types of electric heating systems and prices vary across the spectrum, but all of these thermostats offer substantial potential energy savings and the convenience of remote monitoring and control.

After extensive research, I've identified 10 models that stand above the rest, and in this post, I'll be sharing their key benefits and explaining how they work, so you can decide which one is right for your needs.

From basic models that offer simple app-based temperature control, to more advanced options that dynamically build schedules and track energy usage, there's a smart thermostat for every budget and preference.

What is a Line Voltage Smart Thermostat?

A line voltage smart thermostat is designed specifically for electric heating systems that use baseboard heaters, convectors, in-floor heating, or ceiling radiant heating. 

These smart thermostats work with higher voltage (120V to 240V) as opposed to the low voltage (24V) used by conventional HVAC systems. 

They are also commonly referred to as high voltage thermostats, 120 volts or 240 volts thermostats, 2-wire or 4-wire thermostats, and single-pole or double-pole thermostats. 

Line voltage smart thermostats connect to your home's Wi-Fi, Zigbee, or Z-Wave network, making it easy to control your home's temperature through a smartphone, tablet, or smart home devices like Amazon Alexa, Google Assistant, Apple HomeKit, or other smart hubs.

How Does a Line Voltage Thermostat Work?

A line voltage thermostat works by directly controlling the flow of electric current to an electric heating system. 

When the room temperature falls below the set point on the thermostat, it closes an internal electrical circuit, allowing the flow of electricity to power the heating system. 

As the room temperature rises and reaches the desired set point, the thermostat opens the circuit, cutting off the electric current and causing the heating system to turn off. 

This process of switching the heating system on and off maintains the desired room temperature, providing a straightforward and effective means of controlling electric heating systems.

Safety Considerations

Safety is crucial when installing a line voltage smart thermostat, as these devices operate at higher voltages (120 or 240 volts) than conventional thermostats (24 volts). 

As a result, they can pose a risk of electrical shock or potentially damage your heating system if not installed correctly. I always advise people to seek out the services of a professional, licensed electrician in these scenarios.

Line Voltage vs Low Voltage Thermostats

Line and low-voltage thermostats are designed to control different types of heating systems and operate at different voltage levels. 

Line voltage thermostats (like the Mysa Smart Thermostat) control electric heating systems that operate at higher voltages, typically 120 or 240 volts, and are commonly used with electric baseboard heaters, ceiling heaters, in-floor heating systems, and forced fan heaters. 

On the other hand, low-voltage thermostats (like the Nest Smart Thermostat) work with lower voltage levels, typically 24 volts, and control gas, oil, or heat pump systems often found in central heating and cooling systems. 

The choice between line voltage and low voltage thermostats generally depends on the type of heating system in your home and the voltage requirements of that system.

Single Pole vs. Double Pole Thermostats

When it comes to line voltage thermostats, there are two varieties available on the market: single-pole and double-pole. 

A simple way to determine the type of line voltage thermostat you need is to check the back panel of your existing thermostat. If there are two wires on the back, then it is a single-pole thermostat, and if there are 4 wires on the back, then it is a double-pole thermostat.

Differences

The basic difference between a single-pole thermostat and a double-pole thermostat is that a single-pole thermostat does not have a dedicated “off” setting (However you can effectively turn it off by setting the temperature very low so it’s below the room temperature)

In contrast, the double-pole thermostat comes with a dedicated “off” feature, allowing users to completely turn off the heating system through the thermostat. The choice between single-pole and double-pole thermostats typically depends on the existing wiring in your home and your preference for an “off” setting on the thermostat.

The Sinopé Smart Thermostat supports both 2 and 4 wire installations.

How to choose a line voltage / high voltage smart thermostat?

Compatibility with existing electric heating system

When choosing a high-voltage smart thermostat, it's essential to ensure compatibility with your existing electric heating system. Start by examining your current system's voltage, heating type, and wiring configuration. For example, Mysa has options for different options for baseboard and in-wall versus in-floor heaters. While the Nuheat Thermostat provides dual voltage compatibility (120V & 240V).

Ease of installation and setup

When considering a line voltage or high voltage smart thermostat, ease of installation and setup is an essential factor to keep in mind. A straightforward installation process can save you time, money, and potential headaches. That being said, it’s not worth cutting corners. 120v and 240v systems can be dangerous so if you don’t know what you’re doing, then you should definitely seek the services of a licensed electrician.

Integration with other smart home devices and ecosystems

You’ll need to choose a smart thermostat that is compatible with your existing smart home environment and voice assistants. For example, if your smart home is run on Apple Homekit / Siri, then Mysa and Sinopé are the only brands that support this.

Some devices compatibility with multiple platforms which provides users flexibility when it comes to controlling and monitoring their heating systems, as well as the ability to incorporate the thermostat into their existing smart home setup.

Energy-saving features and efficiency

One of the main reasons to upgrade to a smart thermostat is to save energy and money. These energy-saving features enable you to cut down energy costs while maintaining a comfortable home environment. Some prominent energy-saving features include geofencing, scheduling, usage insights, and ECO modes.

Geofencing allows your smart thermostats, such as the Mysa Smart Thermostat for Electric Baseboard and in-Wall Heaters V2 or the Sinopé TH1124WF, to utilize your smartphone's location to automatically adjust the temperature based on your proximity to your home. This ensures that your heating system isn’t working overtime when you’re out and about, resulting in optimal energy savings.

Scheduling functionality, found in devices like Nuheat SIGNATURE, provides customization of your heating preferences throughout the day or week, putting you in control of energy usage during different times and days.

Usage insights, available in the Mysa Smart Thermostat for Electric in-Floor Heating, display information on your energy consumption, enabling you to make informed decisions about adjusting your usage to save money and resources.

ECO modes, such as those featured in the Stelpro Z-Wave Plus KI STZW402WB+ Thermostat, are designed with energy efficiency in mind. These modes help conserve energy by only using the minimum heating required to maintain the desired ambient temperature.

The Mysa Smart Thermostat v2 is designed to work with high-voltage electric heating systems, such as baseboard heaters and radiant ceiling heaters. It easily connects to popular smart home platforms like Apple HomeKit, Google Assistant, and Amazon Alexa, making temperature control simple.

There are a number of differences between it and its predecessor. It’s 40% smaller than v1 and now supports NFC as well as Wi-Fi. The interface has been improved with audible touch feedback which is a nice design modification. 

It easily blends with your home's decor and offers an adjustable display, customizable brightness, and convenient sleep and wake-on-approach options.

With the Mysa Smart Thermostat v2, you can set your heating schedule and remotely control it through Android or iOS devices. The thermostat also provides valuable information on your energy usage, making energy management more efficient.

Installing and setting up the Mysa Smart Thermostat V2 is straightforward, seamlessly integrating it into your smart home setup. However, it was disappointing to see that some testers and device owners faced connectivity issues with Wi-Fi and certain devices. 

Despite this minor drawback, the thermostat is a smart choice for maintaining a comfortable home while keeping your electric heater energy costs under control.

Enhance your floor heating system with a versatile and powerful thermostat that works smoothly with both heating cables and cable mats. This advanced thermostat includes a dedicated floor sensor, making your indoor steps warm and comfortable, whether you use underfloor heating for warmth during cold months or simply for added comfort.

Easily incorporate this thermostat into your smart home setup, as it's compatible with numerous platforms, including Neviweb, Google Assistant, SmartThings, Amazon Alexa, and Hubitat. What I like about this product is the simple installation process and compatibility with various temperature sensors. Additionally, the thermostat utilizes Zigbee communication technology for a dependable and stable connection, ensuring your home stays cozy consistently.

You can stay in full control of your energy usage with this thermostat's real-time monitoring and display capabilities. You don't have to guess whether your underfloor heating is costing you too much – this thermostat offers an accurate overview of your energy consumption and conservation. 

On top of that, the practical geofencing feature uses location data to enhance energy efficiency, allowing your system to work intelligently around your schedule. 

However, I did find that the app's poor functionality on iPhones could be a potential drawback for some users.

This advanced thermostat stands out for its simple installation and programmability, allowing users to easily control their floor heating system remotely. Whether using the specific Nuheat app or the web portal, adjusting your home's temperature to your liking has never been more convenient.

This thermostat's compatibility with various smart home devices is a significant feature, setting it apart from older models. It works seamlessly with Google Assistant, Nest, Vera, iOS, and Android devices, making your home even more integrated and connected.

Another appealing aspect of this thermostat is the customizable scheduling feature, which helps both increase comfort and decrease energy costs. Users can create a tailored 7-day heating plan based on their specific preferences, giving them more control and adaptability compared to other thermostats.

However, it's worth noting that some users have encountered Wi-Fi connectivity and app issues with this thermostat. Despite its numerous features and advantages, these problems could potentially affect the overall user experience.

The Mysa smart thermostat is a great option for electric underfloor heating systems, offering  compatibility with other brands. Its simple and stylish design turns old-fashioned thermostats into a contemporary home addition.

Installation is quick and easy, usually taking under 20 minutes with the help of online guides and videos. One notable feature of Mysa is its extensive integration with popular smart home systems like Alexa, Google Assistant, and Apple HomeKit. This allows users to control the thermostat remotely and personalize their comfort with geofencing and scheduling capabilities.

Additionally, Mysa provides useful information about your home's energy usage through real-time data. This helps users understand their heating habits and achieve better efficiency. The thermostat's safety features and Class A GFCI protection also make it suitable for bathrooms and kitchens.

However, from my research, I found that testers and device owners reported that the performance was inconsistent and customer support was unresponsive at times, which could negatively affect the overall customer experience despite Mysa's many advantages.

The Stelpro Z-Wave Plus Thermostat is a smart device that allows users to control baseboard and convector heaters through their smartphone app. Its adjustable temperature schedules and eco-friendly mode help achieve a balance between comfort and energy savings.

This thermostat is Z-Wave compatible, specifically designed for line voltage control, allowing it to integrate with other Z-Wave devices like Nexia, Vera, Wink, and SmartThings. This creates a well-connected smart home system, and the easy installation process adds convenience for users.

The thermostat's modern design includes a backlit display housed in a sleek, rectangular form. It can be installed on baseboards or wall-mounted, and the built-in mechanical thermostat ensures efficient operation. UL-certified for safety and quality, it also comes with a five-year limited warranty.

There are some downsides, such as inconsistent reliability and issues with controlling certain heater types. However, the Stelpro Z-Wave Plus Thermostat remains an innovative option for those looking to create a smart home heating system.

The Sinopé's Smart Thermostat (TH1124WF) is a great option for homes with electric heating systems such as baseboard heaters, convectors, and radiant ceiling heaters. Upgrading from a traditional thermostat is smooth, and it provides better control over heating efficiency. The thermostat uses TRIAC switching technology to accurately maintain temperature settings, keeping your home comfortable and saving energy.

What I like about this smart thermostat is its easy installation and compatibility with various devices for remote control. It quickly connects with Neviweb, Apple HomeKit, Google Assistant, Amazon Alexa, and SmartThings, allowing voice commands and simple setting adjustments. Additionally, the geofencing feature in the Neviweb app helps to optimize energy use based on user location.

An upgrade from traditional thermostats, the backlit LCD on Sinopé's Smart Thermostat adapts to ambient light and shows indoor and outdoor temperatures. The user-friendly Neviweb app provides access to real-time consumption data, energy reports, and customizable schedules.

Unfortunately, the thermostat sometimes experiences problems with Wi-Fi connectivity and occasional app issues. Nevertheless, the sleek, rectangular design and straightforward wall mounting make this thermostat both visually pleasing and practical, enhancing the electric heating experience in your home.

The Maestro Smart Thermostat is designed to work smoothly with well-known voice assistants such as Alexa and Google Assistant as well as Samsung SmartThings. This compatibility ensures its seamless integration into various smart home setups. Additionally, its ability to connect with both WiFi and Zigbee technology highlights its flexibility and reliability in diverse smart home environments.

The use of geofencing technology in the Maestro Smart Thermostat allows it to provide location-based temperature control, improving comfort and energy efficiency. The thermostat can detect your movements and adjust the temperature settings automatically, making your home more energy-efficient even when you're not there.

The Maestro Smart Thermostat can potentially lower electricity bills by reducing energy use by up to 25%. Its user-friendly setup and compatibility with a wide voltage range (120V to 240V) make it a suitable choice for homes with varying electrical configurations.

The days of manually adjusting thermostats are long gone. The KING Hoot WiFi Thermostat features app-based controls, letting you change temperature settings easily using your smartphone. With the Hoot app, you can plan temperature shifts according to your preferences and daily routines, ensuring your home stays comfortable and energy-efficient.

I liked how this product consistently maintains a comfortable temperature in different areas of your home. Smart homes need smart thermostats, and this device caters to various residential systems, including 120/208/240V electrical setups. It also has a customizable maximum temperature cap, which helps limit excessive heating, increase safety, and lower energy consumption - making it ideal for environmentally-conscious homeowners.

No more squinting at unclear displays. This advanced thermostat has a large touchscreen and a digital display for easy-to-read temperature readings. Installation is simple due to its compact 2x4-inch size and lightweight design. Embrace user-friendly heating and cooling control with this stylish and practical device.

One downside I saw reported was the limited WiFi network compatibility, as it only connects to 2.4 GHz networks. However, the KING Hoot WiFi Thermostat still remains a competitive choice in the line voltage smart thermostat market.

Like all smart thermostats on this list, the Stelpro Smart Home Wi-Fi Thermostat lets you control your home's heating system with just your voice via Google Assistant and Amazon Alexa. The voice commands, along with personalized heating schedules, make it simple to create a comfortable home environment. I liked that the device has an easy installation and setup process.

Consider your heating becoming smarter with geofencing technology. This Stelpro Wi-Fi Thermostat adjusts the temperature based on your location, improving energy efficiency. You can also use its mobile app to monitor and adjust your home's heating from anywhere. Unfortunately, device testers did encounter some issues with inaccurate temperature readings and unreliable geofencing.

The Maestro Controller connects and automates up to 19 heaters equipped with Maestro-enabled thermostats, providing excellent control for a large home.

The SunTouch ConnectPlus Thermostat allows you to control your thermostat effortlessly with the wireless connection feature. You can adjust and configure it from anywhere using the Watts Home app, which works on both iOS and Android devices. This way, there's no need to make manual adjustments since it lets you adjust the temperature remotely.

I liked that this device is designed to work smoothly with Amazon Alexa and Google Home, allowing easy voice control and improving your smart home experience with a thermostat that listens.

However, I'm disappointed with the potential difficulties some users might face during connectivity and setup, especially with Alexa, and possibly unclear instructions provided.

You can experience efficient energy regulation with this thermostat's intelligent climate adaptation feature. It adjusts the indoor temperature based on the outside conditions, providing a comfortable atmosphere and optimal energy efficiency. Additionally, the consumption monitoring function keeps track of and updates you on energy usage, ensuring you are aware of your smart home's performance.

Pros and Cons (including Customer Feedback)

How I tested

To identify the best line voltage / high voltage smart thermostats, I conducted extensive research using a variety of sources. My research included reading through consumer reports, online reviews, product specifications, and expert opinions.

One of the main things I looked at when narrowing down our list was the compatibility of each line voltage / high voltage smart thermostat with various electric heating systems. I checked the specifications of each thermostat to ensure its compatibility with different voltage and wiring configurations.

I also paid close attention to the features of each thermostat, specifically whether or not it had the ability to learn from user preferences and adjust accordingly, as well as the flexibility of its scheduling capabilities. I also looked at the interface of each thermostat to ensure ease of use and compatibility with a variety of smart home systems.

Additionally, I considered the price of each thermostat and the overall value it provided relative to other options on the market.

Citations

https://getmysa.com/

https://www.stelpro.com/

https://www.sinopetech.com/en/products/thermostat/