When electricians replace room thermostats, they generally need to know if the thermostat is line-voltage or low-voltage. Typically, consumers do not understand the type of voltage a thermostat uses and think of thermostat types as mechanical, programmable, or even wireless. Mechanical engineers and heating-cooling specialists in large buildings, such as shopping malls, schools, and office buildings, are familiar with pneumatic thermostats. Each type of thermometer has specific applications that a consumer should consider before replacing an old thermometer or installing a new one.
Line-voltage thermostats normally work with radiant systems or baseboard heaters. They usually use 240 volts and may control a series of heaters. These controllers are not as dependable as low-voltage thermostats and may turn off the heater before the room has reached the desired temperature. Low-voltage thermostats are common in houses and most businesses. They use 24 to 50 volts and control furnaces and air conditioners.
There are several options when buying low-voltage room thermostats. Mechanical ones are the cheapest and easiest to install. A user manually adjusts the thermostat to the temperature he or she desires. On the other hand, programmable room thermostats will automatically adjust the temperature up or down, depending on a preset schedule. Manufacturers make electronic thermostats for line-voltage and low-voltage systems.
Mechanical controllers generally are slowest to respond to temperature differences. This may cause unpleasant cold spots or drafts during the colder months and hot spots in hot weather. Electronic devices sense temperature changes in a different method and therefore are more reliable.
Some of the advanced technology in heating and cooling devices has created new products, such as the wireless room thermostats. These thermostats have two parts: a receiver and a controller. The receiver is hard wired to the heating or cooling device; the controller signals the receiver when the furnace or air conditioner needs to turn on. One of the advantages of the wireless room thermostat is that a person can move the controller from room to room. For example, if a person leaves the kitchen and goes to the bedroom, he or she can take the wireless thermostat along.
Another type of wireless room thermostats is easier for the homeowner to install. The receiver replaces the existing room thermostat. This is safer for people who are not familiar with a heating or cooling appliances wiring. In some larger homes and buildings, there may be more than one heating or cooling appliance, and each will have its own thermostat. If installing wireless devices, a homeowner should discern if he or she could use separate radio wave frequencies.