Programmable thermostats have a high up-front cost, but they will save you money over the long run if you use them correctly. The best way to use a programmable thermostat is to match it to your sleep schedule. When you are sleeping, you don’t need to heat or cool your home as much as you do when you’re awake. So if you program your thermostat to decrease the heat or air conditioning during sleeping hours, and then to turn back up around when you wake up, you will save a significant amount of energy (and money!).