Common HVAC Problems During Winter (And How to Solve Them)
February 13, 2025
Winter is here, and so is the heavy use of your HVAC system. Whether you rely on a furnace, heat pump, or other HVAC system to keep your home warm, cold weather can present unique challenges for your heating system. To help you keep your HVAC running smoothly during the colder months, let’s take a look at some of the most common HVAC problems that can pop up and what you can do about them.
1. Frozen Coils and Lines
If your HVAC system is freezing during winter, the refrigerant lines or evaporator coils are likely iced over. This is particularly common in heat pumps, but can affect any HVAC system. Frozen coils can prevent your system from operating efficiently and could even cause further damage to components if not addressed.
Why It Happens: Frozen coils can occur due to insufficient airflow, low refrigerant levels, or a dirty air filter.
How to Fix It: The first step is to turn off your HVAC system to prevent further damage. Check your filters and replace them if dirty. If the issue persists, it may be a sign of low refrigerant levels or other mechanical problems that require professional attention.
2. Dirty Air Filters
Air filters are critical to the operation of your HVAC system. In the winter months, it’s easy to forget about them, but they can quickly become clogged with dust and debris, limiting airflow and causing your system to work harder than it needs to.
Why It Happens: Over time, dust, pet dander, and other particles accumulate on your air filter, restricting airflow.
How to Fix It: To keep your HVAC system running efficiently during winter, make sure to check your air filters regularly and replace them as needed—typically every 1-3 months, depending on usage.
3. Thermostat Issues
Your thermostat is the brain of your HVAC system. It tells the system when to turn on and off based on the temperature you set. If it malfunctions, the system may not turn on or off when it should, leading to uneven heating or no heat.
Why It Happens: Thermostats can malfunction for several reasons, including dead batteries, wiring issues, or simple wear and tear.
How to Fix It: If you have a battery-powered thermostat, replace the batteries. If that doesn’t work, consult an HVAC professional to check the wiring or even replace the thermostat.
4. Heat Pump Problems in Cold Weather
Heat pumps are efficient, energy-saving systems for heating homes in the winter, but they can struggle when temperatures drop too low. When the weather gets extremely cold, your heat pump may have trouble extracting heat from the outside air, leading to poor heating performance.
Why It Happens: Heat pumps can struggle in frigid temperatures because they rely on outside air to extract heat.
How to Fix It: Your heat pump may need to be checked for issues like dirty coils or low refrigerant levels. A secondary heating source, such as an electric heater or furnace, may be required to assist the heat pump.
5. Furnace Not Turning On
If you rely on a furnace to heat your home, you may encounter problems with it not turning on at all, even though your thermostat is set to heat. This is a common issue in the winter when furnaces are working overtime.
Why It Happens: This issue can be caused by various problems, such as a tripped circuit breaker, a dirty flame sensor, or a malfunctioning pilot light.
How to Fix It: First, check if the furnace’s circuit breaker has tripped. If it has, simply reset it. If the furnace still won’t start, professional service may be required to inspect the pilot light, flame sensor, or other components.
6. Strange Noises from the Furnace
If your furnace is making unusual sounds, like banging, popping, or rattling, it could be a sign of a mechanical issue or an obstruction.
Why It Happens: Noises can occur due to dirt or dust buildup in the system, part expansion and contraction, or issues with the blower motor.
How to Fix It: Regular maintenance, including cleaning, can prevent some of these issues. If you hear unusual noises, call a technician to inspect the furnace and perform any necessary repairs.
7. AC Not Working in Winter?
Although AC systems aren’t typically used in winter, some may still be running, particularly if they’re part of a combined HVAC unit like a heat pump. If the AC is not working in winter, it may be due to a mechanical issue or user error, like accidentally switching the thermostat to cooling mode.
Why It Happens: The heat may not turn on if you mistakenly set the thermostat to cooling mode.
How to Fix It: Check your thermostat settings to ensure it’s set to heat mode. If your HVAC unit is supposed to handle both heating and cooling, check for any electrical issues preventing the heating system from activating.
8. Common Furnace Problems in Cold Weather
Furnace problems during winter can cause severe discomfort. Some common problems include poor airflow, a malfunctioning thermostat, or even the system short-cycling (turning on and off repeatedly).
Why It Happens: Various issues can cause these problems, including dirty filters, pilot light issues, or faulty motors.
How to Fix It: Check that the furnace is well-maintained by cleaning or replacing air filters and checking the pilot light. Call a professional to inspect the furnace if these simple fixes don’t work.
Preventive HVAC Maintenance
Preventive maintenance is key to avoiding common HVAC problems in winter. It’s always best to schedule an HVAC tune-up before the cold weather sets in, ensuring everything runs smoothly when needed. This service can include checking refrigerant levels, cleaning coils, inspecting thermostats, and replacing air filters—helping you avoid breakdowns when temperatures drop.
Mohr AC Can Help You Stay Comfortable This Winter At Mohr AC, we specialize in HVAC repair and maintenance for homes in all seasons. Our skilled technicians are ready to assist if you're facing furnace problems, heat pump issues, or general HVAC malfunctions. Don’t wait for your HVAC to fail in the middle of winter—contact us today for a professional inspection, tune-up, or emergency repair.