If your home is having a single stage heating system (like a gas furnace) without any cooling function, you simply need a “heat only thermostat” to control the heating system. A heat only thermostat is designed to perform the basic function of regulating room temperature by controlling the heating system (be it a single stage furnace or a heat pump). Usually, a basic heat only thermostat will be having only two switch controls – 1) an On/Off switch and 2) temperature adjustment buttons.
When put to “ON” position or “Heat” position (some thermostats mark ‘On’ as ‘Heat’), the thermostat will turn ON the furnace/heating system and keep it active until the set temperature is achieved. The ‘adjustment buttons’ can be used to increase/decrease temperature to your desired level.
There will be only 2 terminals for a heat only thermostat, marked ‘R’ and ‘W’. You only need to make two connections between your heating system and the thermostat.
Note 1: Some single stage heating systems have a fan to distribute heat faster. For such systems, heat only thermostats with fan switch option is available. These thermostats will have 3 terminals usually, marked ‘R’ , ‘W’ and ‘G’; where ‘G’ terminal is to connect fan of the furnace.
Note 2: Heat only thermostats are also known as ‘2 wire thermostats’. You may read our guide on 2 wire thermostats, which also covers 2 wire single pole thermostats for line voltage systems.
Heat Only Thermostats
Now let’s see all the popular ‘heat only thermostat’ models out there. As mentioned above, a heat only thermostat is basically a 2 wire thermostat with two terminals ‘R’ and ‘W’, which is suitable to regulate a single stage heating system (without any cooling option).
Note: To regulate a single stage heating system, you can actually use any thermostat that supports single stage wiring. For example, Smart thermostats like Nest, Ecobee, and WiFi thermostats like Honeywell RTH9585WF, Emerson Sensi – all supports single stage wiring. You just need to connect the ‘R’ and ‘W’ terminals of these thermostats, and leave all other terminals not connected. So if you want a technologically advanced thermostat with smart features, internet connectivity and smartphone based control, you better choose one above rather than a basic heat only thermostat.
#1 Honeywell TH1100DV1000 Heat Only Thermostat
This is a basic heat only thermostat model from Honeywell, with temperature range 40 deg F to 90 deg F to choose from. It has only 3 buttons, an Off/Heat button on the side and an up/down button on the front to adjust temperature range. This model has a square shaped, backlit LCD display, which displays temperature in an easy to read format. TH1100DV also provides compressor protection feature for the heating system.
If you’re using this model in garage, a mode is available where temperature can be ranged from 35 deg F to 90 deg F.
#2 Emerson 1E78 Heat Only Thermostat
1E78-140 is one of the best selling non programmable heat only thermostat from Emerson. This model is compatible to be used with single stage heat only systems, single stage heat pump and milli volt systems. The display is rectangle shaped LCD, with a back light.
1E78 is designed in such a way as a perfect upgrade to an old mechanical thermostat. The body is designed to cover any wall markings by a mechanical thermostat (old models) and in most cases you don’t need an extra wall plate.
#3 LuxPro PSD010B Heat Only Thermostat
If you need a third choice, PSD010B from LuxPro is a popular non programmable heat only thermostat. This model is compatible with all heat only single stage systems. If your system has a fan, LuxPro has a variant of this same model named PSD010BF – which has additional fan control.
The display is rectangle shaped, with a back light, and it displays only the set temperature. The base model PSD010B has only 3 buttons, an On/Off button and an up/down control. The model with fan (PSD010BF) has 4 buttons, an additional button on the side to control fan operation.