A thermostat timer is part of a programmable thermostat that allows the temperature of a room or home to be regulated according to the time of day. Both analog and digital timers exist, with digital timers generally being more flexible. The unit itself is usually integrated into the standard thermostat of a home, giving it control over the heating and cooling systems that are installed. Many homes use a thermostat timer because of the amount of money that can be saved, and because they work automatically.
The thermostat in a home can use one of many methods to help control the interior temperature. Some thermostats control only the heat in the house while others control both heating and air conditioning via a central air system. Originally, thermostats would be manually set to a temperature and sensors in the home would shut the heating or cooling units down once that temperature was reached. Adjustments had to be made manually, and there were sometimes problems with accuracy.
As systems progressed, the accuracy of the units increased. The first thermostat timers were physical knobs or sliding bars that allowed the homeowner to select a time of day when it would become warmer or cooler. Later units allowed for two such periods, one warmer and one cooler, independent of the normal, set temperature.
Digital thermostats allowed far more complex timing schemes. Often called a programmable thermostat, they provided many more defined periods in a day, each with their own specific target temperature. This was a large advance over simply indicating warmer or cooler.
The use of thermostat timers has increased as energy prices have. One of the main benefits of using a thermostat timer is that the home can have the heating and cooling systems turn completely off during times when no one is home, and then have it turn on shortly before someone will arrive. This can save a large amount of money on a yearly basis. The timer also can be used to make subtle adjustments to the temperature throughout the course of the day.
It is important to know when and how to use a thermostat timer. This includes judging when the warmest and coolest times in the home are, as well as taking into account when people will and will not be home. During comfortable times of day, with no one or few people home, the temperature should be adjusted to use as little power as possible. When the temperatures outside are the most uncomfortable and there are many people home, the thermostat timer should be programmed to operate at peak performance.