Accurate?

I was going upstairs the other evening and the house just felt cold. I looked at the thermostat and it said it was 70* in the house, and I chalked it up to sitting near the fireplace for an extended time. It got me thinking, though, so a couple days later I calibrated a couple of meat thermometers and took them upstairs. I put one on top of the thermostat and one on a dresser in my bedroom. (My room not only has two outside walls, it's also over the garage, so it's colder in the winter and hotter in the summer than the rest of the house.) When I looked at them several hours later, there was a ten degree difference between the thermometer and the thermostat. Not surprisingly, the bedroom was another five degrees colder. I found the website for the thermostat, and it claims that the accuracy is +/- 1/2 degree. That didn't stop me from bumping up the temperature another five degrees to what I thought it was in the first place, and the house is much more comfortable now. I wish I'd thought to check that sooner.