Calgary Furnace Replacement | | Call (403) 800-8956! The modulating furnace is the best among the three types of furnaces. It has a brain attached to the gas pedal. When it’s colder, it gives it a little more gas. As it warms up, it coasts. It gives your house exactly what it needs. No more. No less. Give us a call at Accu-Temp to find out how modulating furnaces in Calgary is the best choice for you.