How to Convert a Heater Thermostat to Digital

Thermostats are in every household, but have you ever wondered how they work?

A mechanical thermostat consumes more electricity than a digital one because it's inherently inaccurate. It maintains a higher temperature than its setting and it allows the temperature to fall below its setting before re-energizing the heater, which uses up more power.

In contrast to this, a digital thermostat provides better accuracy and control, resulting in a savings in electricity consumption [source: DIY Doctor].


Here's what you'll need to replace a wall-mounted thermostat with a programmable digital one:

  • A programmable digital thermostat
  • A screwdriver
  • A pencil or dowel
  • A cordless drill (optional) [source: Donovan]

Here's how to replace that thermostat:

  1. Turn off the thermostat's circuit breaker.
  2. Remove the thermostat cover by either pulling it off or removing the screws, depending on the model.
  3. Remove the mounting screws and gently pull the thermostat away from the mounting plate.
  4. Label each wire with the symbol or letter of its thermostat terminal.
  5. Disconnect the wires from the thermostat and wrap them around the pencil or dowel so they don't slip back into the wall. Important: If the thermostat contains a mercury tube, don't toss it in the trash. Ask your local waste management authority how to dispose of it safely.
  6. Remove the mounting plate from the wall.
  7. Align the new mounting plate over the hole. If the screw holes don't match up with the existing anchors, hold the plate level and mark new holes with the pencil. Drill the holes and insert new anchors.
  8. Pull the wires through the mounting plate and then screw the plate firmly to the wall.
  9. Check the thermostat's terminals for symbols or letters. If the markings match the wire labels, connect the wires to the corresponding terminals. If the terminal markings are different, check the installation or user's guide for wiring instructions.
  10. Snap the thermostat onto the mounting plate, and then insert the batteries. Note: Some models require you to reverse this procedure.
  11. Turn the circuit breaker on.
  12. Switch the thermostat to Auto and set the thermostat higher than the temperature reading. The heater should switch on within a few seconds.
  13. Program the thermostat according to the user's manual [source: Donovan].


Convert Thermostat FAQ

Can I replace a thermostat myself?
It is possible to replace your old thermostat yourself, but you‘ll need some basic electrical knowledge and have to carefully follow the instructions to do it properly and safely.
Are digital thermostats better than analog ones?
Digital thermostats are much better than analog or mechanical thermostats. Analog thermostats not only use more energy, but also maintain a higher temperature than their setting. On the other hand, a digital thermostat is more accurate and offers more control, resulting in energy savings.
How do you identify thermostat wires?
Once you have pulled the thermostat away from the mounting plate, the best way to identify thermostat wires is by looking at the thermostat terminal each of them is connected to.
What is a smart thermostat?
A smart thermostat is a type of thermostat that can be used with home automation devices, which means it can be controlled with a phone or tablet app or smart speaker, whenever and wherever.
How do you take off the cover of a thermostat?
In order to take the cover off a thermostat remove it by either gently prying it off or removing the screws, depending on the model.