If you’re looking for a thermostat, you might be seeing different models built for the variety of furnaces that exist out there. Terms such as one-stage, two-stage or multi-stage are confusing, but we’re here to clear up the confusion.
Single stage (one stage)
Single stage furnaces have only one speed and temperature output. Likewise, they only have two modes: on or off. When the thermostat reads that a room has grown too cold, the furnace activates and heat is output until the room reaches the right temperature.
Dual stage (two stage)
A dual stage furnace, as the name suggests, has two stages of operation. Besides the simple on or off, it has an intermediate stage which can be anywhere from 50-75% power. This allows the furnace to operate much quieter and not use as much energy.
Your thermostat should be tailored to the type of furnace you have. Attaching a dual stage thermostat to a furnace that is only single stage will not give the furnace newfound abilities. Again, it’s the furnace that dictates the type of thermostat you should have. Most homeowners in the US and Canada have single stage furnaces, and Orbit thermostats are designed to work with single stage furnaces.