Heating is the main event here
In Sioux Falls, the furnace earns its keep. NOAA's engineering weather data puts the 99% winter design temperature at −11°F, and the 50-year frost depth reaches 102 inches. Summers are warm but much drier than in the South. This checklist puts the heavy work in late summer and fall, when a missed problem would leave a house cold in January.
Late August and September: the most important visit of the year
- Book the heating inspection while technicians still have open calendars. The first cold week in October brings a rush of no-heat calls.
- Ask for a combustion and safety check on gas furnaces: flame sensor, heat exchanger inspection, draft and carbon monoxide readings.
- Replace the filter and buy a season's supply in the right size.
- Test carbon monoxide alarms and replace any older than the manufacturer's stated life.
October and November: seal the house for winter
- Check exterior intake and exhaust pipes for high-efficiency furnaces. Mark their location so you can find them under snow.
- Shut off and drain outdoor hose bibs if they are not frost-free, and close any humidifier bypass damper the right way for the season.
- Set the whole-house humidifier carefully. Too much moisture in subzero weather condenses on windows and inside walls. Ask your technician what setting suits your house.
December through February: deep cold
- Clear snow from the furnace vents after every storm, and from the heat pump if you have one. A blocked intake will shut a furnace down on the coldest night.
- Keep a backup plan. Know where your space heaters are, how to reach an emergency service line, and what to do if the house drops below a safe temperature.
- Watch for short cycling or a burner that lights and quits. Call early instead of waiting for a total failure.
May and June: the cooling check
NOAA counts about 232 hours a year in Sioux Falls with the wet-bulb temperature above 73°F, far fewer than in the Gulf states, so cooling loads are lighter. Still:
- Uncover and clean the outdoor unit if you covered it for winter, and make sure it sits level after the ground thaws.
- Run the AC once on a warm day before the first hot spell.
Storm season: protect the outdoor unit
During the May 12, 2022 derecho, straight-line winds of 50 to 70 mph were widespread across the region, with smaller areas of 80 to 100 mph. After a severe storm, look for bent fins, a shifted pad, damaged line-set insulation or debris in the fan before restarting the system. If the unit has moved or the refrigerant lines are kinked, leave it off and call for service.
If you replace equipment
South Dakota is in the Department of Energy's North region, where new split-system central air conditioners must be rated at least 13.4 SEER2. Ask any contractor to list the matched indoor and outdoor model numbers so you can check the pair's rating, and ask how the new furnace was sized for a −11°F design day.