HVAC in Minneapolis is what stands between a cold night and a burst pipe. Furnaces and boilers are not comfort accessories here. A high-efficiency unit can shut itself down when the condensate line freezes, and the house finds out at dawn when a north-wall faucet is solid. Thermostat setbacks that look reasonable will freeze a rim-joist line. If the heat is off now, say that before any other symptom. The pipes are already on a clock.
Report a dead blower, a hot smell, a short cycle, banging ducts, or a draft hood that spills. Lake-flat wind and a tall chimney still change draft on the worst nights. If the air feels wrong, get people to fresh air and lead with that. A boiler leak is not a furnace failure. Do not mix them. Filters clog over a long run and still are not the story if the house is already losing temperature. Say which rooms lagged first, especially rooms over a garage or a cantilever.
Summer is real, humid, and secondary. A condenser packed with seed will not dry a second floor. Window units in bungalow openings drip on plaster and come out in the fall, when the furnace takes the house back. Say if you are calling in July so nobody treats it as a freeze. Unsealed attic ducts sweat and also leak the heat you need in January. A closed return starves a furnace that otherwise seems fine.
Have the fuel and the type. A tune before the season is not a no-heat call tonight. Replacement is not a condensate-line repair, and that repair is sometimes the whole emergency. Backup heat that is a single space heater should be called missing. If the thermostat was set back, say how the house was left. An empty weekend and an occupied night are different risks. The sequence is what the next trade will ask about the pipes.
Lead with no heat, a frozen condensate line, a leaking boiler, or rooms over cold air that never catch up. Say whether any faucet has already gone solid. Minneapolis will not give you a mild night to experiment. Call the number on this page.