Winter in East Tennessee can drop below freezing in hours, and a single missed step can turn your heat pump into an ice block. Below are five easy steps you can take now to keep your HVAC system running smooth all season.
Step 1: Keep Airflow Unrestricted With a Clean Filter
Good airflow is the lifeline of any furnace or heat pump. When the filter gets clogged, the blower works harder, the coil can get too cold, and ice may form. A clean filter lets air move freely and stops the system from overworking.
We recommend checking the filter at the start of each cold spell. Turn the system off, slide the filter out, and look for visible dust. If it’s dark or dusty, replace it with a new one that matches the size printed on the frame.
Monthly checks are a habit that saves energy and protects components. Clean filters help maintain airflow and reduce strain on HVAC parts. In East Tennessee, we often see homeowners skip this step once the leaves start falling, only to face a frozen coil weeks later.
When you install a high‑MERV filter, watch the airflow. Very dense filters can restrict flow if the system isn’t designed for them. If you notice weaker air coming from vents, downgrade to a lower‑MERV option until the next professional tune‑up.
Pro Tip: Keep a spare filter in the garage so you can swap it out quickly on a rainy day. By now you should have a fresh filter installed and airflow restored.
Step 2: Protect the Outdoor Heat Pump Without Covering It
Outdoor units are built to survive snow, rain, and cold wind. A full‑wrap cover can trap moisture, block the little airflow the unit still needs, and invite rust or rodent damage.
Our experience in East Tennessee shows that most homes do fine with the unit left uncovered, as long as you clear snow and debris regularly. If a storm drops several inches of snow, use a broom to remove it from the top and sides within a few hours.
When you need extra protection, choose a rigid, vented shelter that sits over the unit like a roof, not a tight tarp. This keeps large snow loads off the coils while still allowing air to pass.
The Wikipedia entry on heat pumps notes that proper ventilation is important for defrost cycles to work. Blocking that airflow can cause the sensor to misread temperature and freeze the coil.
Check the area around the unit for overhanging branches or leaf piles that could drop debris. Trim back vegetation at least two feet from the unit’s sides.
By now you should have cleared the space, inspected for damage, and set up a vented cover only if needed.
Step 3: Check Thermostat Settings and Watch Heating Cycles
Thermostat mis‑settings are a common cause of frozen components. If the thermostat tells the heat pump to run at a temperature lower than the room actually is, the unit runs longer and can over‑cool the coil.
Set the thermostat a few degrees higher than the comfort set‑point during extreme cold. For most East Tennessee homes, 68°F when you’re home and 60‑65°F at night works well.
We also suggest using the “hold” function on smart thermostats to avoid short cycles that confuse the defrost timer.
For a deeper dive on optimal winter settings, Best Thermostat Settings for Tennessee’s Changing Weather. It explains the recommended ranges and how to program them.
Watch the run‑time on the thermostat display. If the system runs continuously for more than an hour without reaching the set temperature, something is wrong , either a sensor issue or a blocked airflow problem.
Key Takeaway: A correctly set thermostat prevents unnecessary run time and gives the defrost cycle a chance to work.
Step 4: Monitor Frost and Respond Safely to Ice Buildup
Even with good airflow and correct settings, a sudden cold snap can cause ice to form on the outdoor coil. Spotting frost early stops bigger problems.
Look for a thin white coating on the coil fins after a night of sub‑zero temps. If the ice is thicker than a quarter inch, turn the system off and let it melt fully before restarting.
Never try to chip the ice off with a hammer or metal tool , you could damage the fins. Instead, use a garden hose on a gentle spray to melt the ice, or let the sun do the work if it’s a sunny day.
After the ice melts, run the system on “heat‑only” mode for a few minutes to clear any remaining moisture.
Our preventive checklist (see 15 Preventive HVAC Maintenance Tasks to Extend Your System’s Life) reminds homeowners to inspect the unit for frost after any freeze‑over event.
By now you should have removed the ice safely and confirmed the unit runs without abnormal noises.
Step 5: Schedule a Professional Winter Inspection Before Freezing Weather
DIY care goes a long way, but a certified technician can spot hidden issues that cause freezing , like low refrigerant pressure or a failing defrost sensor.
We recommend booking the inspection in early December, before the first hard freeze. Our team checks refrigerant levels, electrical connections, sensor calibration, and the defrost cycle.
During the visit we also verify that any R‑454B or R‑32 refrigerants are handled correctly, as these newer blends need special care.
Clients who follow this schedule see fewer emergency calls and lower energy bills, because the system runs at its designed efficiency.
Read more about why a full‑season check‑up matters in our Heat Pump Freeze Protection: A Step‑by‑Step Guide. It outlines the exact items our technicians inspect.
Pro Tip: Ask the technician to set up a reminder in your smart thermostat for the next year’s inspection.
FAQ
What causes an HVAC component to freeze?
Ice forms when airflow is restricted, the coil gets too cold, or the defrost cycle fails. Clogged filters, covered outdoor units, and thermostat errors are the most common triggers.
How often should I change my air filter in winter?
We suggest checking the filter every month during the heating season and replacing it if it looks dirty. In homes with pets or allergies, a monthly change is safest.
Do I need to cover my outdoor unit in East Tennessee?
No, a full‑wrap cover usually does more harm than good. Keep the area clear of snow and debris, and use a vented shelter only if you face heavy snow or ice storms.
Can I fix a frozen coil myself?
You can melt surface ice with a gentle water spray, but if the ice keeps returning you should call a pro. Repeated freezing often means a sensor or refrigerant issue that needs professional repair.
When should I schedule a winter inspection?
Book the appointment in early December, before the first deep freeze. This gives our technicians time to catch low refrigerant, faulty sensors, or wiring problems before they cause ice buildup.
Conclusion
Start with a clean filter, keep the outdoor unit open, set the thermostat right, watch for frost, and let Jack Frost Heating & Air Conditioning, Inc. perform a pre‑winter inspection. Call us today to lock in your service date and enjoy a warm, worry‑free winter.