Best 4 Wire Thermostat – The Ultimate Guide


If you’re looking for a new best  4-wire thermostat, it is common to experience challenges choosing from many products.

Understanding what 4-wire thermostats are and how they can help you make a more confident, informed decision.

This article will explain these concepts and list the five best 4-wire thermostats on the market.

Table of Contents

What is a 4-wire thermostat?

4-wire thermostats work by having four wires connecting the unit to the primary source of electricity.

The biggest difference between a 2-wire or 3-wire thermostat and a 4-wire model is that they have an extra cooling wire to help regulate and manage the current more effectively.

One of the biggest benefits of a 4-wire thermostat compared to smaller configurations is that you can use them interchangeably.

As a 4-wire model contains all the wires you will find in a 2-wire or 3-wire configuration, it is fairly easy to connect.

Additionally, the thermostats can automatically decide whether to route power to the HVAC system’s heating, cooling, or fan functions.

What does the wiring color represent?

Red is the first wire color (abbreviated to Rh), providing and controlling the main power supply.

The second color you need to know is yellow (which you can abbreviate to Y), the cooling wire.

Yellow wires are unique to 4-wire configurations, so you will not see them in 3-wire or 2-wire configurations.

Another color you should understand is white.

The abbreviated version is W, and they are the heating wire. Green is the fourth and final wire color, which you will find on most thermostats and controls power to and from the furnace’s or heater’s fan.

One piece of information to remember is that you may sometimes see a blue wire.

It is the same as a yellow wire, but the color differs depending on the brand, creating an element of inconsistency across different products.

Best 4 Wire Thermostat

1. Honeywell Home Manual 4 Wire Baseboard/Line Volt Thermostat

Honeywell Home Manual 4 Wire Baseboard/Line Volt Thermostat

Features & Benefits

  • Firstly, this is not a smart thermostat, so it is easy to use and has a more classic feel.
  • Secondly, it detects the home environment using a bi-metal temperature sensor, allowing for more reliable, accurate readings.
  • Thirdly, it operates in the 120 to 240 volts range, meaning it is more likely to be compatible with your current setup.


  • It has a predefined temperature range, so it may not work with your application.

Customer Reviews

“They work well and are affordable. If one breaks, they are easy to replace (including installation).”

2. Dr. Infrared Heater DR-001 Wall Thermostat

Dr. Infrared Heater DR-001 Wall Thermostat

Features & Benefits

  • This thermostat has an intuitive wall mount design that sits perfectly flush against most walls.
  • It also includes celsius- and Fahrenheit-based control dials, making for a more widespread and inclusive experience.
  • Furthermore, the double terminals mean the controls use a positive OFF position, improving safety and usability.


  • It can be quite challenging to set up due to limited instructions.

Customer Reviews

“Very effective and safe solution for controlling my garage heater.”

3. Honeywell Home Programmable Touchscreen Thermostat

Honeywell Home Programmable Touchscreen Thermostat

Features & Benefits

  • Firstly, the controls are on a large touchscreen display, making it easy to configure your heater.
  • Also, it includes many features such as 7-day programming, home and away temperatures, and more.
  • Finally, the entire display has a high-quality backlight to make it easy to use at night.


  • The installation manual is unclear and confusing, so it could be hard to set the unit up.

Customer Reviews

“This has been a great unit for us, and it’s certainly nice not having to slide the temperature adjuster every morning.”

4. Honeywell Line Volt Thermostat

Honeywell Line Volt Thermostat

Features & Benefits

  • Firstly, the electronic temperature control is highly precise and accurate, saving as much as 10% on heating bills.
  • Additionally, the frame soundproofs the thermostat to ensure it can operate as quietly as possible.
  • Lastly, the display has a bright backlight to program your heater throughout the night easily.


  • You can only program night and day temperatures, not random daily intervals.

Customer Reviews

“This one is great. Simple to install and simple to set up!”

5. Emerson Sensi Wi-Fi Smart Thermostat

Emerson Sensi Wi-Fi Smart Thermostat

Features & Benefits

  • Firstly, the company that makes this product guarantees that it will not sell your personal information to third parties.
  • Secondly, it is quick and easy for you to install the unit independently.
  • Furthermore, the smart features provide usage reports and equipment alerts to help monitor your HVAC system’s performance.


  • Buyers frequently report bad customer service experiences.

Customer Reviews

“Very quick and easy install. No disappointments”


This article explained how 4-wire thermostats work and what all the different colors mean. It also listed the five best products for you to consider.