The room thermostat (see Figure 4-25) is regarded as the nerve center of the heating and cooling system because it controls the operation of the furnace, boiler, or air conditioner. Ideally, it should be mounted in an area of the living or working spaces where it is not subjected to temperature or moisture extremes.
Low-voltage room thermostats are recommended over the line voltage types for residential heating and/or cooling systems. The low-voltage thermostats respond more quickly to temperature changes and will maintain the temperature and humidity more closely than the line voltage types. A low-voltage thermostat requires the use of a transformer to reduce the line voltage for the control circuit, but the cost of the transformer is more than offset by the lower installation cost of this thermostat.