My parents have steam radiators, and they can't use programmable thermostats because the cycling time isn't suitable for the boiler. Or something. [insert more detailed explanation that boils down to, they say it works, and for some boilers it's ok, but not for their boiler] Rather than risk damaging their very old boilers by cycling them too often, they got a modern, non-programmable but electronic thermostat. No more dial! The temp will range about +/- 5 degrees, just because that's part of the deal with how their boilers were designed to operate.