Here in the South, many homeowners rely on their HVAC systems to provide both cooling in the summer and heating in the winter. While these systems are designed to work year-round, they can face unique challenges when the temperature drops during winter. One of the most frustrating issues is when the HVAC unit starts freezing up during colder weather. When this happens, it can reduce the efficiency of your system, and in some cases, cause it to stop working altogether.
At Checkup Property Inspections, we know how important it is to maintain a comfortable home, no matter the season. That’s why we’re here to help you understand why your HVAC system may freeze up during the winter, how to prevent it, and what to do if it happens. With a little proactive care and routine maintenance, you can avoid a frozen HVAC unit and keep your home warm all winter long.
Why Do HVAC Units Freeze in Winter?
Unlike heat pumps, which are specifically designed to provide both heating and cooling, many HVAC systems in the South are designed to switch between air conditioning and heating by using separate systems for each. These units generally use a furnace for heat and a separate air conditioning unit for cooling. However, even these systems can freeze during the winter, especially if certain conditions aren’t managed correctly.
When the outdoor temperature drops significantly, it can cause the condenser coils on your air conditioner to freeze up, even though you’re using the heating function. This occurs because the unit is still using the cooling components to circulate refrigerant, but the cold outdoor temperatures cause the moisture in the air to freeze on the coils. If the system isn’t properly maintained or if airflow is restricted, this ice buildup can prevent the HVAC system from functioning properly.
Ensure Proper Airflow Around the Outdoor Unit
One of the main causes of freezing in an HVAC system is poor airflow. If your HVAC unit’s outdoor coils are covered by debris, dirt, or even leaves, it can restrict airflow, causing the system to work harder than it should. When the coils aren’t able to release the heat they absorb properly, the temperature of the coils can drop too low, leading to ice buildup.
To prevent this issue, make sure to regularly clean the area around your outdoor unit. Trim back any plants or shrubs that may block the airflow, and clear away leaves and debris. If snow or ice accumulates around the unit, make sure it’s cleared off as soon as possible to ensure that the unit can function properly. Additionally, consider installing a cover for the outdoor unit during particularly cold spells to protect it from excessive ice and snow buildup.
Change the Air Filter Regularly
One of the simplest but most effective ways to help prevent freezing is by maintaining the airflow inside your home. When the air filter in your HVAC system becomes clogged with dust and debris, it can restrict airflow, which in turn makes it harder for the system to maintain proper temperatures. This puts extra strain on the unit and can lead to freezing problems.
It’s essential to check and replace your air filter every 1-3 months, especially during the winter months when the system is running more frequently. A clean filter allows the system to breathe easily, promoting better airflow and reducing the chances of the coils freezing up. If you notice a drop in airflow or your system isn’t warming your home as efficiently as usual, check the air filter and replace it if necessary.
Avoid Setting the Thermostat Too Low
Another factor that can contribute to freezing is setting your thermostat too low, especially during very cold weather. While it may seem like a good idea to keep the temperature set lower to save on heating costs, setting the thermostat too low can cause your HVAC system to struggle. When the temperature inside drops too much, the system may work overtime to warm up your home, which can lead to freezing issues.
Try to keep the thermostat set to a moderate and comfortable temperature, generally between 68°F and 72°F, to avoid overworking the system. Lowering it too much may cause the HVAC unit to run continuously, potentially leading to frozen coils if the temperature outside is too cold. Using a programmable thermostat can help you manage the temperature more efficiently and ensure that your HVAC system isn’t running unnecessarily during the night or when you’re away.
Check the Condenser Coils for Ice Buildup
Even with proper airflow and regular maintenance, sometimes ice will build up on the condenser coils, especially during colder stretches of weather. When this happens, it can drastically reduce your HVAC system’s efficiency, or even cause it to stop working entirely. The coils can freeze if the refrigerant pressure is too low, the system is working too hard, or the defrost cycle isn’t functioning correctly.
If you notice frost or ice accumulating on the outdoor unit’s coils, it’s important to turn off the HVAC system and allow it to thaw. Continuing to run the system while it’s frozen can damage the compressor and other components. After turning off the unit, let it thaw naturally by turning on the fan or using a hairdryer (set to low and held at a distance) to speed up the process. Once the system has thawed, check for any signs of leaks or damage that could be affecting the refrigerant pressure.
Inspect the Ductwork and Vents
Restricted airflow isn’t just an issue with the outdoor unit. Blocked or damaged ducts inside your home can also affect the performance of your HVAC system, especially during the winter. If air ducts are leaking or becoming disconnected, it can cause uneven heating and force your HVAC system to work harder. This increased strain on the system can lead to freezing problems.
Take the time to check your ducts for any signs of leaks or blockages. Ensure that your vents are open and unobstructed to promote proper airflow. If you suspect issues with your ductwork, it may be worth scheduling a professional inspection. Addressing ductwork problems early on can improve system efficiency and prevent issues like freezing.
What to Do if Your HVAC System Freezes
If your HVAC unit does freeze up, there are a few steps you can take to address the problem. First, turn off the system immediately. Running the unit while it’s frozen can cause damage to the compressor and other components. Allow the system to thaw completely before you attempt to turn it back on.
Once thawed, check the air filter and condenser coils for any ice buildup or debris. If you notice any damage or suspect an issue with the refrigerant, it’s a good idea to contact a professional HVAC technician. They can assess the system, check for refrigerant leaks, and perform any necessary repairs. If the defrost cycle isn’t working properly, a technician can inspect the timer and components to ensure it’s functioning as intended.
How Checkup Property Inspections Can Help
At Checkup Property Inspections, we offer thorough inspections of your home’s systems, including your HVAC unit. While we don’t handle HVAC repairs directly, we can identify potential issues that may lead to freezing problems before they become major concerns. During our inspections, we’ll check for signs of airflow issues, clogged filters, and possible airflow blockages that could be contributing to your HVAC system freezing up.
With our professional assessment, you can catch problems early and take the right steps to keep your system running efficiently all winter long. A simple inspection can save you from costly repairs and provide peace of mind knowing your heating system is in good shape.
We Are Here to Help
Preventing your HVAC system from freezing during the winter requires regular maintenance, good airflow management, and awareness of how temperature settings affect system performance. By taking a few simple steps, such as cleaning the outdoor unit, changing your air filter regularly, and maintaining your thermostat at a moderate temperature, you can keep your HVAC system running smoothly even during the coldest months of the year.
If you do experience freezing, remember to turn off the system, allow it to thaw, and check for any potential problems. And if you’re unsure about the condition of your HVAC system, Checkup Property Inspections is here to help with comprehensive home inspections that give you peace of mind during the winter season. We’ll ensure your home stays warm, and your HVAC system stays in good working order, so you can enjoy the season comfortably.