Here are the three main furnace types compared in one simple table: comfort, noise, gas use, typical Calgary installed cost and who each one suits best. Single-stage furnaces keep costs low, and two-stage furnaces hit the sweet spot for most family homes. Modulating furnaces deliver premium comfort and the lowest running costs. Whether you're replacing an old unit or building new, this guide from Purcell Heating & Air makes choosing your next furnace quick and easy.