Quote Originally Posted by JLC
I would imagine if you're at least mildly mechanically inclined...and have a rudimentary understanding of electronics...it's probably not hard at all. But I've never done it myself, so I'd wait for a more exprienced voice to answer that one.
They are'nt real complicated, but if you have never seen how one was wired it could be very tricky to figure out. The best way to make sure it is wired right is to buy a prewired unit. Really by the time you buy the wire etc and spend the time doing it, you might as well have them do it. Especially if you do it wrong and fry the thermostat they will not replace it. If they do it wrong then they will have to replace it.