Definition
The appliance that heats air by burning gas (or using electricity) and pushes it through your ducts. The workhorse of most Minnesota homes.
Why this matters for your home
A gas furnace burns fuel in a sealed combustion chamber, transfers that heat to your air through a heat exchanger, and the blower pushes the warmed air through your ducts. Electric furnaces use heating elements instead, but gas dominates here for its lower operating cost in deep cold.
A well-maintained furnace lasts 15–20 years in Minnesota, though hard winters and skipped maintenance shorten that. As a unit ages we watch the heat exchanger, ignition, and flue closely — both for efficiency and for the carbon-monoxide safety margin that matters in a tightly sealed home.