Exactly what I've been questioning all along. We don't even know what the objectionable temp swing is. Any decent thermostat that is properly installed will control the temp at the thermostat to 1.5 deg or so. And if that is objectionable at the thermostat, then what about the rest of the house, where the temp swings are almost always greater? In fact, with short cycleing, which is what he appears to want, the temp fluctuations in the rest of the house might be worse.