Is it better (cheaper/more efficient) to keep a thermostat set at a constant temperature or program it to adjust the temporatures up and down during the day and night?

Robert England, October 2003

Programmable thermostats save energy and also you can use them as a weather compensation system so that if it has been a really cold night the heating comes on to a low level (say 12 degrees) about an hour before you want it to come on normally. I.e. if you want 18 degrees at breakfast time at 8am you set 12 degrees for 6.30 and 18 degrees for 7.30. Set it back to minimum last thing at night (effectively off but gives freeze protection). Best value are Horstmann Centaurstat giving 6 settings per day and can be different each day. Cost £28.99 from Screwfix.com

John H, May 2007