Homeownership can be a humbling thing.

And humiliating. Or, in the alternative, it can be a great opportunity to learn something new every day.

Today, for instance, I learned that my thermostat, hooked in to the electrical system as it is, is not actually operated by electricity from the electrical system. It runs off of two AA batteries. And when they go dead, no more heat is generated, despite the fact that there's oil in the tank and the electricity is still connected.

It was somewhat after dark this evening, temperature outside plunging through the upper 30s on their way to below freezing, and the cat decided that my lap would be a good place to hang out. And my hands were becoming numb. Hmm, that's odd, I thought. It was nice and toasty in here earlier today. So I put the cat down (wrapped in a blanket, so she wouldn't get cold) and went off to see what the matter was. The furnace hadn't disappeared (I could do the same thing to correct that as I could with the furnace present, of course - nothing at all), and the lights were on. Maybe I should check the thermostat to see whether the cat had turned it off, as I knew that I surely had not. Traipsed upstairs to the thermostat - and the LED digits showing time and temperature were missing. Okay, I had no clue what to do at this point - has the thermostat died? Has something in the furnace acted up and the thermostat could detect it and shut it down? Is there a short in one of the wires leading to the thermostat? Should I call the heating/electrical company now and order a new furnace? Do I need to have them come out and take a look at the system, and if so, can it wait until tomorrow morning so I can avoid an "after-hours" charge? Then I noticed a recessed button that I could push. So I did - what could it hurt? And the cover came off. There's another button I could pull on, and another cover came down, revealing two batteries, one of which was covered with that dried gunk you get when a battery leaks.

Took me another ten minutes to find my tool box and get a screwdriver so I could pry out the batteries and replace them, and another twenty minutes to re-program the thermostat (warm during the day, cooler at night), and voila! the heater came back on. So did the LED temperature indicator - it had dropped to 60 on the upstairs floor where the thermostat is.

And the best part is that I avoided having to buy a new furnace.