I am buying a new Programmable thermostat for our church.
What is difference between single stage and 3 heat-2 cool stage thermostats?
Thanks

First, What type of thermostat are you replacing, is it a multi stage t-stat? Single stage would be your basic furnace/air handler and A/c, 2 or more stages heat/cool would be for example- a 2 speed air conditioner, basically what this is, the compressor and fan can run on either high or low speeds, it's supposed to be an energy saver, same thing with a 2 stage furnace.