First, check what you’re currently using. You’ll likely stick with the same source to avoid massive installation costs. Most common, highly efficient, and uses natural gas.
In the HVAC world, bigger isn't better. A furnace that’s too large will "short cycle" (turn on and off constantly), wearing out the parts. One that’s too small will run forever and never get you warm. how to buy a new furnace
Don't wait for your current furnace to die in the middle of a blizzard. Researching now gives you the leverage to find the best deal and the right pro for the job. First, check what you’re currently using