What does "1 or 2 stage" refer when talking about a thermostat?

I'm going to install a programmable thermostat. The one that I want says %26quot;Works W/most 1 Or 2 Stage Systems%26quot;. What does this mean and how do I find out what type of system I have?



Thanks!What does %26quot;1 or 2 stage%26quot; refer when talking about a thermostat?A one stage thermostat is one that only controls one unit. So if you have window air conditioners and a furnace for heating, its a 1 stage system.



The two stage systems control two units. Some people have one furnace for the first floor, and one for the second floor. This would be a 2 stage unit.



If you have two heat units, and central air it would be a 3 stage system.



My house has a furnace and central air, and we have a two stage system. We just put in a programmable thermostat that was for 2-4 stage systems. Since we only have 2 stages, we had less wires to connect and we kept a jump wire in.What does %26quot;1 or 2 stage%26quot; refer when talking about a thermostat?Heat pumps have two stages in which case you need a heat pump thermostat. Some of the newer furnaces have two stages of heat.

There are some a/c units now that have two stages. Some electric furnaces have two or more stages of heat.

You could write down what color wires are connected to what terminal designation you have now on your thermostat. This would tell someone experienced what you have.