Tim says: "The experts at the Energy Saving Trust and British Gas say it's cheaper to heat your home only when you need it. But my heating control panel says that it uses less energy to keep a background temperature when the room is unoccupied, than it does to allow the dwelling to chill too much. I'm confused! Which advice is correct?" We put Tim's question to Mike Childs, head of science, policy and research at Friends of the Earth. Also helping us out is Lewis Tyronney, an engineer with British Gas... Like this podcast? Please help us by supporting the Naked Scientists