As above, is it an easy DIY job to do this safely?
In my research into the above it has become apparant that I should consider replacing the old thermostat with a programmable one for energy savings. How does a programmable thermostat produce savings? I assumed the whole point of the thermostat in the first place was that the heating wouldn't be on if it was below the desired level anyway.
Replacing a thermostat is trivial, and similar to changing a light switch. Disconnect the two wires coming from the furnace/boiler, then reconnect them to the new thermostat. Turn off power to the furnace/boiler first.
A programmable thermostat saves fuel and money because it can be programmed to lower the temperature when you sleep or are at work.
It doesn't matter which brand you pick, but most of them have horrible user interfaces, worse than old VCRs and clock radios.
To answer the first question:
Replacing the thermostat is equivalent to changing a light switch.
You need to turn the power to the central heating off before you start work.
Unscrew the old thermostat, disconnect and then reconnect the new one. What you will need to make sure before you do this is that the new thermostat has the same terminals as the old.
Do you have a particular thermostat in mind? If so can you provide a link, then we'll be able answer the second question more easily.
To lend support to ChrisF ... it's very easy to change your thermostat. Every place I've lived in has had the old mercury trip thermostat, wildly inaccurate. I just went to my local home depot and for about $25 I picked up a nice programmable digital thermostat. Was a snap to replace and works prefectly !!
Like other answers indicate, this is pretty simple, and a great idea if you're going from a manual to programmable thermostat. I can't comment yet, but thought it important to point out that there are (at least) two different types of thermostats. Some work for forced-air furnaces, and others work for radiators. Make sure you get the right kind.
