I bought this thermostat as it is the first one Heatmiser has made with a 0.5degC switching differential. My previous one switched on 1degC differential and has been in since 2006. With underfloor heating, particularly in a large room, a drop of 1decC before the stat switches on is too big but 0.5deg gives the room more even temperature control and has made us more comfortable. Unbelievably though, you can only set the room temps in 1deg increments, despite the fact that it indicates to 0.1deg!!! So, much improved over the 2006 model, but still lacks an design input by someone who actually uses it to control underfloor heating.