This was a replacement for a thermostat that stopped working after 6 years. I figure that's not bad. We had a programmable one, but didn't change the temp, so we bought the core/standard one this time. Just a warning - don't even CONSIDER that you can put this in yourself, even as a replacement unless you're a licensed electerician/builder. Just the instructions made my eyes bulge. But our friend, a contractor, put it in, took about half an hour or more. Worked like a charm. From 66, it went to 81 degrees and toasty within the hour. I love the radiant heat, it's in our bathroom.