That constant hum from your basement isn’t just the sound of winter; it might be your furnace working harder than it should. If your heating system seems to run all day and night, or you notice it kicking on and off too frequently, it’s time to pay attention. A furnace that runs constantly is more than an annoyance; it could be an underlying problem that wastes energy, drives up bills, and risks a mid-winter breakdown.
At Northern One Hour Heating & Air Conditioning, we understand the importance of reliable heat during a Minnesota cold snap. Here’s what might be causing your furnace to run nonstop, and what you can do to help it work more efficiently this season.
Thermostat settings may be the culprit
Sometimes, the issue starts with your thermostat. If it’s set too high or the fan setting is switched to “ON” instead of “AUTO,” your system may blow air constantly, even when heating isn’t needed.
Try setting the fan to “AUTO” so it only runs during heating cycles. If that doesn’t help, consider whether your thermostat is aging or inaccurate. A newer programmable or smart model can do a better job of maintaining consistent comfort and preventing overwork.
Dirty filters restrict airflow
A clogged air filter can force your furnace to run longer than necessary. When dust builds up, air can’t move freely, making it harder for your system to reach the set temperature.
Replacing your filter every one to three months, especially during peak heating season, helps your furnace breathe easier and keeps your home warmer with less effort. If you’re unsure which filter your system needs, a technician can guide you in the right direction.
For more guidance on keeping your system running smoothly, see our page on furnaces.
Leaky ducts or poor insulation can waste heat
In many Twin Cities homes, especially older ones, duct leaks or poor insulation are the silent culprits behind high energy bills and running furnaces. When warm air escapes through gaps or unsealed areas, your furnace works harder trying to replace the lost heat.
Having your ducts inspected and sealed can make a big difference. Adding or upgrading insulation helps, too, keeping heat where it belongs and giving your system a well-earned break.
Short cycling signals a deeper issue
If your furnace turns on and off frequently but never seems to warm the house evenly, you might be dealing with “short cycling.” This can happen when the system overheats, the thermostat is malfunctioning, or internal components like sensors need attention.
Short cycling not only wastes energy but can also lead to wear and tear over time. If it’s happening often, it’s worth having a professional take a closer look. Routine furnace repair can identify and fix small issues before they turn into larger, more expensive problems.
Your furnace may be undersized or aging
Even a well-maintained system can struggle against Minnesota’s deep freeze if it’s too small for your home—or simply reaching the end of its lifespan. When that happens, the furnace runs constantly trying to keep up, but never quite delivers.
If your unit is more than 15 years old, or your home has changed significantly since installation (such as added square footage or insulation upgrades), it might be time for a performance evaluation. A properly sized system can heat your home more efficiently while reducing strain and energy costs.
Keep your home comfortable all winter
A furnace that runs nonstop isn’t always an emergency, but it’s never something to ignore. Paying attention to small signs early, like frequent cycling or uneven heat, can prevent bigger problems later.
If your system still struggles after basic checks, scheduling a professional inspection is the next best step. The certified team at Northern One Hour Heating & Air Conditioning provides reliable heating care throughout the Twin Cities and nearby communities, helping homeowners stay warm and worry-free all season long.Schedule service or call (763) 319-0872 to book a visit at your convenience.