Replace Your Old Thermostat
An electronic thermostat is a big improvement over an old manual one
Jun 6, 2007
I had put off taking out my old dial thermostat for many months, thinking that it was a complicated job to install a new electronic one. Was I ever wrong. It was one of the easier jobs I've tackled, and I love the convenience of a programmable thermostat.
Now, these are just the basic instructions for installing an electronic thermostat. Your home wiring or HVAC system may be different, so be prepared to think on your feet. The overall process is the same, but the wires that you find may vary. Your new thermostat should come with a good instruction guide, which should include how to deal with a number of wiring configurations.
Old thermostats are wired at very low-voltage, so there is very little shock risk. I replaced mine without turning off the power, but I'm not necessarily recommending that to anyone. Flip the breaker to cut the power, to be on the safe side.
The first step is to remove the cover from your old thermostat. It might just pop off, or there might be screws holding it in place. Don't remove the entire unit yet, just the front plate or cover.
Inside your old thermostat, there will be a number of wires, all fastened to points inside the unit and disappearing back into the wall. Each wire will be labelled (either on the wire itself, or at the connection point) with a letter. With labels that come with your new thermostat, or pieces of masking tape, clearly mark each wire.
Disconnect each wire, taking great care not to let them fall back into the wall. The labels are likely large enough to keep them from falling through the hole, but you need to watch them. Wrap them around a pencil, or clip them together with a large binder clip. The last thing you need is to have to fish a skinny little wire back up through that hole.
Once all the wires are disconnected and labelled, then you can remove the rest of the old thermostat unit from the wall. You should now have a hole in your wall, with a number of wires sticking out.
Your new thermostat will have a hole in the back for the wires to come through. Pull the bundle of wires through, and place the unit against the wall. Use a level to make sure it's straight and attach to the wall, using the screws provided. You can also use anchors if you wish, though I have never felt the need to.
Ok, now you have your new unit in place and it's time to reconnect all those wires. Read the instruction manual carefully at this point. Depending on your existing wiring, you will likely only have to match up the wires (G goes to G, and Y goes to Y, for example). But your manual will explain how to arrange the wires if the letters are not the same. Most configurations can be adjusted for.
Put new batteries in your thermostat, and put the front cover in place. Your thermostat should be up and running at this point. You will need to follow the manufacturer's directions to learn how to program the unit.
By having your heat (and air conditioning) adjust itself automatically when you are not at home, you can save quite a bit on your utility bills. Not to mention you will be helping out the environment at the same time.
