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Written by Eric Sherwood | April 14, 2024
With temperatures sinking to 20º F and lower during winter, Wisconsin residents need a source of reliable heat to make it through the coldest days of the year. Temperatures can get even more frigid at night, making sudden furnace failures even more problematic for local families.
In this blog post, the heating experts at All Comfort Services cover five common reasons why your furnace might stop working at night and what you can do to get it to regain total functionality.
Before you panic or call for help, it’s essential to understand some common reasons why furnaces tend to shut off at night:
A clogged air filter is one of the most common reasons for a furnace shutting off unexpectedly. While it might sound like a minor issue, clogged air filters can significantly impact your system’s performance. Air filters trap dust, debris, and airborne particles, preventing them from entering your furnace and affecting efficiency.
When filters become too clogged, airflow is restricted, resulting in overheating and subsequent system shutdown as a safety precaution. To prevent this, clean and replace your air filters at the recommended intervals, ideally once every one to three months.
Poor airflow throughout your home can also lead to sudden furnace failures. Inspect vents and grates to ensure they’re open and unobstructed.
Blocked vents can prevent proper circulation, leading to overheating and automatic shutdown of the furnace. By keeping vents clear and ensuring adequate airflow, you can help ensure your system operates reliably through long winter nights.
Another potential reason is that it’s the incorrect size for your property. Furnaces that are too large for your home can experience short-cycling. This is when the furnace rapidly turns on and off, leading to increased wear and tear on the system and reduced efficiency.
If you think your furnace is oversized for your home, you’ll need to have a professional HVAC technician perform an evaluation and provide a heating replacement recommendation that’s better suited to your property’s needs.
A dirty flame sensor is another common culprit behind sudden furnace shutdowns at night. The flame sensor is responsible for detecting whether the burner’s flame is present and shutting off the gas supply if it’s not.
Over time, the sensor can become coated with soot or debris, which may not be easily detectable during the day but can significantly impact it at night.
Cleaning the flame sensor is a relatively simple task that can be achieved with a piece of fine-grit sandpaper or steel wool. However, if you’re uncomfortable doing this alone, it may be best to trust a trained professional to ensure proper cleaning and maintenance.
Older furnaces rely on a thermocouple to control the gas line via a pilot light. If the thermocouple is dirty or malfunctioning, it can keep the furnace from staying lit through the night, causing it to shut off prematurely.
While cleaning or replacing a thermocouple is more involved than other maintenance tasks, it’s essential to ensure proper furnace functionality — especially in older units.
If you suspect a failing thermocouple is behind your furnace shutdowns, it’s best to have it inspected and serviced by a qualified technician.
Professional maintenance is the best way to keep your furnace functioning properly during the winter. All Comfort Services specializes in providing comprehensive furnace tune-ups to families throughout Dane County.
With 100% satisfaction guaranteed and a strong tradition of service excellence, you can rest assured that our team will keep your furnace in top working condition all winter.
Schedule your furnace tune-up today by calling our team at (608) 838-7300.
HVAC Service Manager Eric has over 25 years of industry experience and relocated from Vermont to be near his grandchildren.
He’s been married for 25 years. He enjoys spending time with grandkids, traveling, camping, hiking, fishing, hunting trying new restaurants.
His biggest hobby is remodeling houses, and his favorite dog is Australian Shepard- his current dog is an Aussie Doodle.
