If you're only a little cold, whack on a jumper and some warm socks. Or get a space heater. You'll save a lot of cash by just using it for whatever room you're in, rather than central heating to warm up the whole house. Obviously, if you live in a climate with super-cold winters, this isn't going to be an option. But maybe look into a programmable thermostat which you can set to a lower temperature at night, when you can wrap yourself in doonas and use an electric blanket.