I spent the last couple nights rewiring a good share of our furnace room. A little background, when they built our house they installed a very basic thermostat. It wasn't even programmable. But after a gas bill that I would consider to be excessive, it was time to change that.
I could've just swapped it out for a $20-30 5-2 programmable model you can get anywhere but that's before I heard of the Honeywell IAQ from the fountain of all knowledge. It's a state-of-the-art system that controls everything to keep it running as efficient as possible. You can only find them on eBay since they're only sold to contractors. But since the cheapest I saw them for on eBay was $130, I had to talk to the wife. After telling her the whole story with absolutely no bias whatsoever (I swear!), she surprisingly said, "well I live with a geek, we pretty much HAVE to get the cool one!"
Fortunately, I managed to snipe one off eBay for a mere $96. Tonight, I got the fun of drilling a hole in the side of the house so I could run an outdoor temperature sensor. Check out the attached pictures. This little beauty is now controlling our furnace, A/C, humidier and air exchanger.
(No comments about the outside temperature!)