In this post we will cover the best 2 wire wifi thermostats for you home. Smart wifi thermostats are great addition to any home but the options are far more limited when you only have a 2 wire heating or cooling system.
2 Wire Thermostat Systems: What You Need To Know
2 Wire HVAC systems generally fall into two categories which are heat only or cooling only systems. These systems can then be either high voltage or low voltage thermostats. It’s important to know what kind of system you have before you choose the a 2 wire wifi thermostat for your home. We’ve listed the most common type of 2 wire HVAC systems below. If you know if you have a high voltage or low voltage heating or cooling system you can skip below to the list of best 2 wire thermostats but if not we’ve listed the type of systems and how to tell them apart. High voltage systems aren’t compatible with 2 wire wifi thermostats but, most typical HVAC systems are low voltage systems and are compatible with 2 wire thermostats.
Types Of 2 Wire HVAC Systems
Boiler System (Low Voltage Controlled)
Radiant Floor Water/Steam Heated System (Low Voltage Controlled)
Heat Only Furnace With Blower (Low Voltage Controlled)
Cooling Only Air Handler With Blower (Low Voltage Controlled)
Radiant Floor or Baseboard Electrical Heating System (Low Voltage Controlled)
Radiant Floor or Baseboard Electrical Heating System (High Voltage Controlled)
Do You Have a High Voltage or Low Voltage Thermostat?
If you know what style of HVAC system you have you can use the list above. If not you can determine if you have a high voltage or low voltage thermostat with the following steps.
You will need a multimeter, we recommend the either of the two multimeters below.
Turn off the power to your HVAC system
Gently remove your existing thermostat from the wall and position it in a way so that the the wires won’t short circuit. Take the thermostat cover off if needed. You will need to have enough access to touch the thermostat terminals with your multimeter probes.
Turn on your multimeter and set to AC voltage.
Turn the HVAC power back on.
Place your multimeter probe to each terminal or wire connected to the thermostat and take a voltage reading. If the voltage is approximately 24V you have a low voltage thermostat. If the reading is approximately 120V then you have a high voltage thermostat.
Best 2 Wire Wifi Thermostats (Low Voltage)
#1 Nest Thermostat Generation 3
The Nest Thermostat is not only the best 2 wire wifi thermostat but it is one of the best wifi thermostats you can get for your home. The Nest Generation 3 thermostat can be used with heating only and cooling only systems and requires only wires. Either the heat wire and the power wire (W & Rc or Rh) or the AC wire and power wire (Y and Rc or Rh).
Nest Thermostat Features
The Nest Thermostat is a smart thermostat that allows you to remotely control your heating and cooling using your phone or a compatible voice assistant like Alexa. You can adjust your heating and cooling, check the temperature in your home or even turn your HVAC system off all from your phone with the Nest Thermostat. Beyond allowing you to remotely control your Nest Thermostat with your phone the thermostat is packed with smart features that can help you save energy and live more comfortably.
Home / Away Mode - The Nest Smart Thermostat has built in motion sensors that detect if you are in your home or away from the house. If you enable the Home/Away mode the Nest Thermostat will automatically help you save energy when you’re away from your house by setting your thermostat to more energy efficient settings while you’re at work or on vacation automatically.
Auto Schedule - The auto schedule mode on the Nest Thermostat uses data from your daily routine on when you wake up, go to work and make adjustments to your thermostat to optimize the thermostats temperature based on your daily activities. The Nest learning algorithm makes adjustments overtime to perfect the schedule for maximum comfort
Airwave - This Nest feature works with your air conditioning to help you save energy and money by circulating the cool air in your HVAC system after your air conditioning compressor shuts off. This helps maximize the efficiency of your HVAC System.
Eco Mode - This mode allows you to set an energy saving temperature range that your Nest Thermostat will manage when you are away from your home, this means that your house won’t get too hot or too cold in Eco Mode but will allow you to save energy when your away. You can also just set your Nest Thermostat to Eco Mode on a nice day if you want to save energy.
The Nest Thermostat does not require a common wire in most cases. Even when set up as a 2 wire wifi thermostat. However if your Nest Thermostat needs more power through a common wire it’s easy to add a common wire and we teach you how to add a common wire in another post.
#2 Nest Generation E Smart Thermostat
The Nest Generation E Thermostat is a less expensive version of the Nest Thermostat. It also functions as a 2 wire wifi thermostat. It has most of the same features of the higher end Nest Thermostat but is made from plastic instead of stainless steel and glass like the higher end Nest Generation 3 thermostat. The only other big difference is the Nest E has a slightly lower resolution (320 x 320) vs (480 x 480) than the Nest Gen 3. The difference in resolution is negligible on such a small device to begin with and most people would probably not notice it.
The Nest Gen E Thermostat can be a big saving in comparison to the Nest Thermostat without compromising on functionality. Some people even like the white look of the Nest E Thermostat better because it blends into a white wall when off.
The Nest E still allows you to control your smart wifi thermostat from your phone or with Alexa or Google Home voice assistants using your voice.
Best 3 Wire Wifi Thermostat (High Voltage)
Mysa Smart Thermostat For High Voltage Radiant Floor or Baseboard Heating
The Mysa 3 wire wifi thermostat is unique in that it is a high voltage thermostat designed to work with high voltage electric heating systems. It’s a great thermostat that serves a very specific nice and if you have a high voltage heating system.
You can control the Mysa thermostat from your phone and it also works with HomeKit, Alexa and Google Home making it fully compatible with the most popular voice assistants.
The Mysa Thermostat replaces existing high voltage thermostats and will work with both iOS android phones. The Mysa app is clean and easy to use and is designed to allow you to control your wifi thermostat from anywhere.
On the Mysa App you can set schedules, monitor your energy usage and set geo fencing boundaries that will tell your smart wifi thermostat to save energy when you go to work or leave the boundary.
The Mysa thermostat requires 3 wires because it is high voltage and if you are concerned about your heating system being compatible with the Mysa Thermostat it’s best to watch the installation video below to see if you have the right wiring configuration.