When temperatures outside are extremely cold, it is normal for some extra cycles to occur. When a furnace is short cycling, it's working hard to produce heat but isn't making any, causing strain on your furnace. If left unchecked, this could cause major issues for your furnace resulting in hefty repairs.
Some of the most common causes of a short cycling furnace include: Dirty air filter. When your air filter is dirty, it will block airflow to your furnace and cause your system to overheat. This can trigger your furnace's limit switch, which will shut down your furnace even if your home isn't properly heated.
Cold weather can put more demand on the furnace, leading to longer run times and higher energy consumption. Extremely cold temperatures can also cause the furnace's exhaust pipe or intake pipe to freeze, which can block airflow and affect operation.
Dirty filters are the most common culprits of this problem. Poor ductwork installation is another one. Blocked air returns, closed vents, or dirty furnaces all can cause similar problems. You might also have an evaporator coil with a layer of lint covering it.
When temperatures drop below zero or even below freezing for extended periods of time, sometimes your furnace can't keep up. If your home is not heating up to the temperature you've set, try lowering it a few degrees. The temperature of the air coming out of your vents doesn't get warmer by turning up your thermostat.
Heater Not Working In Cold Weather
First, check your thermostat: Verify it has power and fresh batteries. Ensure it's set to “Heat” mode. Test if it responds to temperature adjustments.
Furnaces, boilers, and heat pumps were not designed for temperatures in the -5ºF to -10ºF (and below) range—they were designed for outdoor temperatures dipping to 0ºF. And when you have wind chills near the -20ºF mark, as we have right now in this cold snap, your HVAC system is going to work much harder than usual.
If your furnace shuts off after a few minutes and starts more than eight times an hour, it may require repair. Common causes of furnace short cycling include restricted airflow, a malfunctioning flame sensor, or a poorly placed thermostat.
Winter weather often leads to increased dust and debris in the air. If the filters in your HVAC system become clogged, it can restrict airflow. It puts a strain on the system and can cause a breakdown. Freezing temperatures can cause pipes, coils, and other parts of your system to freeze.
Yes, the outside temperature significantly affects your HVAC system's performance. Both heating and cooling systems need to work harder in extreme temperatures, leading to increased energy consumption and potential strain on the system.
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.
The simple solution: Turn your furnace off and check the filter. If it's dirty or it's been 3 months or more since you changed it, put a new, high-quality filter in place.
This can happen anywhere from three to eight times an hour, depending on the condition of the furnace and the outdoor temperatures. If it cycles too frequently or only runs for a minute or two before turning off, there may be a problem with the furnace.
If your furnace keeps turning off, check for issues such as: Dirty Air Filters. A clogged filter restricts airflow, causing the furnace to overheat. Replace air filters every 60 to 90 days to prevent this problem.
Short cycling is a common sign of a bad flame sensor. The sensor thinks that there isn't a flame, so it shuts off the gas as a safety mechanism. Except, there is a flame and without the gas to supply it, it dies. This is a frustrating problem, but an HVAC technician can fix it.
Dirty Air Filters
So, the furnace is triggered to stop, then it cools down only to fire back up again. This short cycling continues to repeat until the furnace receives the airflow it needs. Dirty air filters are one of the most common reasons behind furnace short cycling.
During unusually cold days your furnace can work harder than usual. Read more about furnace tips in extreme cold weather. If you live in an area that typically doesn't experience extreme freezing weather, the heating system in your home may have trouble keeping up.
When the outside temperature is in single digits your furnace will run close to 60 minutes per hour. It will either run continuously, or it will shut off for a short time period and then come back on for long cycles. This is normal, and it is okay.
Heat Pump Issues
Simply put: heat pumps don't play the best with excessively cold weather. Several problems can be present with the heat pump of an HVAC system, but the most common problem that can result in a unit shut down is a frozen heat pump or a heat pump that is not draining.
It could be that the thermostat batteries are low or that there is a wiring issue preventing the thermostat from signaling the furnace to run. Your furnace could also be faulty or not getting an accurate temperature reading and thus not signaling the furnace to run even though your house is cold.
Heating systems were generally designed before climate change became a commonly accepted concept, meaning they weren't engineered to be able to withstand extremely cold temperatures. As the weather gets more unpredictable, you need to be ready to give your heating system a helping hand when temps turn frigid.
On extremely cold days, homes with gas furnaces are at risk of a specific problem – freezing.