Line voltage thermostats are used to regulate heating/cooling systems that run on direct electricity (line voltage – 120 volts or 240 volts). A classic example is baseboard heaters which operate on line voltage. We’ve reviewed baseboard heater thermostat models in our previously published guide. Line voltage thermostats are usually known in different names like line thermostats, inline thermostats, high voltage thermostat, 120 volts/240 volts thermostat, single pole/double pole thermostat or 2 wire/4 wire thermostats. All these names refer to the same one type – line voltage thermostat. In this guide, we help you to identify your heating/cooling system ( your thermostat type) and choose a line voltage thermostat model that best suits your heating system.

However, there are different types of thermostats to serve unique functions. You have to buy the right thermostat that serves your purpose.  A little research before buying would help you choose the right thermostat model and save you a lot of extra expenses. In this article, we review line voltage thermostat models (aka line volt thermostat) which are thermostats that uses direct line voltage to function (say 110 volts). Line volt thermostats are usually used to control heating equipment like baseboard heater, room heater etc.

When we speak of thermostats, they are basically of two types, namely line voltage thermostat and low voltage thermostat.

This article helps you make better choices while you shop for line voltage thermostats.First and foremost thing you should know before you buy any device is its basic function.So what is actually a line voltage thermostat and what is its area of application?

What is Line Voltage Thermostat?

Line voltage thermostat is a type of thermostat that uses the direct line voltage(USA: 110V). This type of thermostat is used in households that have baseboard heater or electric heater. A line volt thermostat usually has thick wires ( two or four wires) coming out of its back. They are mostly installed in series with the heaters at line voltage and switch on and off the mains power to the heaters, according to temperature settings. The shortcoming for this type of thermostat is that, the thermostat may reach the set room temperature even before the heater brings the room to the set temperature, thus shutting of the heater early than desired.

The figure below shows a typical line voltage thermostat, with its wires coming out of its back.

Backside:Line Voltage Thermostat (4 Wire/Double Pole)

Now, you might have a basic idea of what a line voltage thermostat is, but still got second thoughts to go for the line voltage thermostat or low voltage thermostat – right?.

Let us clear that for you, follow the bullet point nutshell explaining difference between the two.

Note:- In any case, please note that a low voltage thermostat is not suitable for appliances like base board heater, electric room heater, heat pump, radiant heater etc. You should buy a line voltage thermostat for these appliances mentioned. Keep that noted.

Differences: Line voltage and Low voltage thermostat

  • Line voltage thermostat uses direct line voltage, whereas low voltage thermostat works at a lower voltage than the line voltage.
  • Line voltage thermostat is used mostly for electric heaters or baseboard heaters, whereas low voltage can be used for central heating systems including furnaces, air conditioning, split heaters and boilers.
  • Line voltage thermostat have thick wires whereas low voltage thermostat has multiple thin wires, as they mostly work at a voltage in the range 24V -50V.
  • The low voltage thermostats are more efficient in controlling the current than the line voltage thermostat.

Coming back to the line voltage thermostats, let us have a look the different models available in the market.

Different models available in the market

The earliest model of a thermostat was possibly built by a Dutch innovator Cornelis Drebbel in 1620, to regulate the temperature of a chicken incubator. Since then many models have been built and available in the market.

You have plenty of options floating in the market to choose from. However, the line voltage thermostats models can be broadly divided into two category; one being digital and the other one being manual line thermostats.

We have reviewed some of the models available in market in both the categories that will help you decide the best option for you.

Digital Line voltage Thermostats:

Digital Line Voltage Thermostats – as their name suggests use digital temperature sensing for precise temperature control. Here you can set a temperature and this device will automatically monitor the temperature within 1 degree or less precision of your set point. In market, there are three types of digital line voltage thermostats available namely: Programmable, Non-programmable and Wi-Fi line voltage thermostats.

Some of the latest models are reviewed below.

Programmable Line Voltage Thermostats:

#1 – Honeywell – 7 Day Programmable Line Volt Thermostat

Programmable Line Volt Thermostat – Honeywell

This Honeywell TL8230A1003 Line Volt thermostat, uses a 7 day programmable memory that gives you flexibility of either using the pre-set schedule program or modify the schedule as per your needs. It has a large and clear backlit display. With a temperature control precision of (+/-) 1F  and an early start feature, it promises to save an additional 10%  (Honeywell claims 20% total savings if you follow preset schedule) on heating bills and ensures that the programmed temperature is reached within time.

If you are technically equipped, the installation is quite easy, only you may find some trouble figuring out how to program your own schedule. However once up and done, this battery free, double pole (4 wire) thermostat is one of the best options you can get your hands on.

Important Specs:

  • Operating voltage – 208 to 240 volts AC
  • Current – 15Amps Max
  • Power – 3600 Watts at 240V and 3120 Watts at 208V.

Best suited for:  Electric Baseboards, Convectors and Fan Forced Heaters (Resistive Rated Loads), Color White, Application Heating.

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#2 – Aube – Digital Programmable Line Voltage Thermostat

Digital Line Voltage Thermostat – by Aube

This thermostat model from Honeywell comes with a 7 day programmable memory and battery free back up that ensures you don’t have to reprogram your schedule in case of power outage. This thermostat adjusts heat every 15 seconds that helps in maintaining the room temperature well within +/- 1F precision, sans large temperature swings.  This single pole, 2 wired thermostat is compatible with electric baseboard, radiant ceilings convector and fan-forced heaters and promises you a hassle free installation experience. It also comes with a early start function ensuring the programmed temperature is reached by programmed time. It works with 120V, 2000W (max) and 240V, 4000W max. However one downside for this model is you cannot adjust the temperature beyond its factory set options.

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#3- King (ESP230-R )Electronic Line Voltage Programmable Thermostat

Line Volt Programmable Thermostat – Kings

This line voltage thermostat has a programmable memory that enables you to set the temperature at different times of the day thus promising an energy cut down up to 28%. It also has a 3 minute cycle that eliminates short power bursts that are wasteful and may cause potential damage to your heaters. With two manual controls below the screen, it is easy to program and use. The programmable controls are placed safely beneath the front cover to protect it from wandering and unauthorized fingers. This Three wired, 2 pole thermostat works in the temperature range of 44-95 degrees F and has a rating of 208/240V, 22 Amperes.

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 #4 – Stelpro STE402P+W Digital 5-2 Day Programmable thermostat

Line Volt Digital Thermostat – Stelpro

The STE402P+W is one of the good options, if you are looking for a wall mounted line voltage thermostat that controls electric baseboards, fan forced wall ceiling, floor or toe-kick heaters. It comes with unique features such as total silent operation, frost free warning and off position, a lock option that would set a maximum room temperature even during manual overdrive. It works in 120V , 208 and 240V. It has schedules pre-programmed which can be accessed by simple buttons. Also, you can program it according to your needs at a maximum of 4 periods per day. This single pole, two wire thermostat has an accuracy of (+/-)  1F and a current rating of 15 Amp.

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Wi-Fi Line Voltage Thermostats 

We have seen 4 models which are Line Voltage Programmable Thermostats. Now lets see 3 advanced models which has the WiFi feature, where you can control the thermostat wireless.

Stelpro KI STZW402WB+ Line Voltage WiFi Thermostat

Stelpro – Line Voltage WiFi Thermostat

If you are looking for a smart line volt thermostat to use with 240V electric baseboard, then this device is for you. It pairs well with your Z-Wave systems and is easy to install. It works well with both 4 wire and 2 wire systems and offers variable heating, that heats the room only when it is needed, thus promising a cut in your energy bills. It supports upto 4000W. It does not have a built in scheduler as it is mainly intended to be used with your Z wave systems that don’t need one.

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Honeywell – E-Connect Wireless Line Volt Smart Thermostat

Honeywell – Line Volt Smart Thermostat

An intelligent thermostat, the YTL9160AR100 comes with both programmable and non programmable memory. It is an equipment interface module, meaning all the HVAC equipments are wired to a single module. It has a return air sensor, that ensures maintenance of safe indoor temperature in case of power is lost at the thermostat. Its wireless signals do not interfere with other wireless equipments at your home, thanks to the red link wireless technology used in this product. Installation is easy and when used with c7089r1013 wireless outdoor sensor, it displays the outdoor temperature and also gives a 2 month low battery warning. Works best with Fahrenheit baseboard type strip heater.

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Nuheat AC0055 – WiFi Touchscreen Dual Line Voltage Thermostat

Nuheat – Touchscreen Line Volt Thermostat

The first Wi-fi enabled thermostat in North America, this device is specifically designed for electric floor heating systems. You can use the free Nuheat SIGNATURE smartphone app or any browser to monitor, control or program this device from anywhere. It has a super intuitive 3.5” touchscreen display that would display the useful energy saving information and weather updates. It comes with built in class A GFCI protection and works at 120 V and 240V and has a current rating of 15A.  It has an ambient sensor that is not enabled by default. It can also be used for baseboard electric heaters.

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Non- Programmable line voltage thermostat

Honeywell TL7235A Line Volt Non-Programmable Digital Thermostat

Honeywell – Line Volt Digital Thermostat

Looking for a non programmable double pole line thermostat, that can be used for your electric baseboards, convectors and fan forced heaters? Then Honeywell’s TL7235A1003 is a good option for you. It is soundproofed for silent operation and also has a on demand backlit LCD display that enables easy reading in all lighting conditions. It has electronic sensors that ensures a temperature accuracy of . It has a heating indicator to let you know whenever the heating is on. The temperature range is 40 to 86F and current rating is 15A at 240V.

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Honeywell YRLV310 Digital Non-Programmable Thermostat

Honeywell – Digital Non Programmable

The YRLV310A1026/U digital Nonprogrammable thermostat from honeywells is a two wire single pole device that is most optimal to be used with 120V,and 240V electric baseboard heating, convectors and radiant ceilings. It supports upto 3000W at 240V and is easy to use and install. It uses TRIAC switching that enables silent operation eliminated the usual clicking noise a conventional thermostat makes. It has accuracy as low as A downside to this product is the absence of backlit display, that makes reading in dark a bit tough.

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StelPro Electronic Line Voltage Non Programmable  thermostat

Stelpro – Line Volt Digital Non Programmable Thermostat

This device from STELPRO, is a high quality single pole, two wire digital line voltage thermostat that is quite easy to use. It controls upto 4000W at 208V , 240V or 2000W at 120V. It has a temperature range of 37 to 48 F. It comes with a frost free warning and off setting. It has a feature that enables night setback mode in which you can program a temperature setting for a desired duration, at the end of which the thermostat returns back to its regular daytime setting. This process repeats every 24Hr and does not need resetting.

Honeywell RLV312 Line Volt Digital Non-Programmable Thermostat.

Honeywell – Line Volt Non Programmable Thermostat

The RLV3120A1005/E1 model of line voltage digital thermostat from honeywell is a non programmable device apt for electric baseboard heating. It has a straightforward installation process and includes hardware. They can run at reduced capacities and have a silent operation that is they do not produce clicking noise during switching on and off. It is rated for 1000kW at 120V and 2000W at 240V. Temperature accuracy is  and uses a TRIAC switching. Apart from the electric baseboard heaters this device is compatible with convectors and radiant ceiling applications having a minimum resistive load of 0.83A and maximum resistive load of 8.5A.

Manual Line Voltage Thermostats

Manual thermostats are the ones that are commonly referred to as old fashioned line thermostats, for the simple reason that in this digital era, this non programmable thermostats use vapor filled bimetallic strips to sense the temperature instead of an electronic sensor. However they are still in use, mainly because these are very economical and easy to use.

Here we have listed best selling models of manual line voltage thermostats available in the market.

# The most popular model:

Honeywell Manual 4 Wire Premium Baseboard/Line Volt Thermostat

Honeywell – Line Voltage Thermostat

This manual line thermostat from honeywells is one of the most popular models available in the market because of its various features. It is easy to install and use, anyone with basic wiring knowledge can install. It uses bi-metal temperature sensor and has a mechanical operation. A knob is provided all you need is to turn it and set the temperature you desire. These are compatibile with 120V,240V baseboard and can control upto 5280 watts. It comes with 2 pole and 4 wires.

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# The economical model:

Honeywell CT30A1005 Standard Manual Economy Thermostat

Honeywell – Standard Manual Line Thermostat

 Looking for something simple and economical that would give optimum performance and still be budget friendly? Then CT30A1005 model from Honeywell is the answer. It is easy to use and install and also this product is mercury free. It uses a bimetal temperature sensor. It has a mechanical operation but is doesnot have a “off” switch. It comes with single pole and 2 wires.

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# Manual Thermostat with premium design:

HoneyWell T498B1512 Electric Line Voltage Thermostat

Honeywell – Premium Manual Thermostat

This Honeywell thermostat uses mercury based thermometer and has a sleek premium design. It is compatible with electric baseboard heaters and includes positive off switch. It has no inductive resistance and is rated at 22A at 120/208/240V. You can set the temperature in the range of 40F to 80F. It comes with locking cover and knob decal that helps in recaliberation.

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So let’s conclude our review of the best selling line voltage thermostat models available in the market. These are our picks in regard to the same. It is up to you to decide what features you want in your thermostat. If you are technically comfortable and have a budget on the higher side, going for digital thermostats will be a good choice. However, if you have a budget on the lower side, manual thermostats are not only easy to use, they have a straightforward installation as well. Temperature accuracy is better in digital thermostats. Also, nowadays with the power of internet and wireless communication you can get weather updates right on your LCD display of your digital line thermostats.