How to Prepare Your Heat Pump for Vermont Winter
May 10, 2026
The right time to prepare your heat pump for Vermont winter is September or October. The system has finished cooling season, you want it clean before peak heating, and our calendar is at its lightest. Here is the full pre-winter checklist.
The September/October window
Two reasons to book before November:
- Buildup from summer cooling needs to come out. Cooling mode creates condensation, which feeds biofilm. By October, three months of biofilm is sitting in the air handler. Heating mode will dry it but not remove it.
- Our calendar fills tight in November and December. Once people notice musty smells from the first heating cycle, demand spikes. Booking in September means same-week availability instead of two-week waits.
If you missed September, October still works. November is fine if you can get a slot.
The pre-winter checklist
1. Book an annual cleaning. Non-negotiable if it has been more than a year. $199 first unit, 60-90 minutes per indoor head.
2. Wash all filters. Soapy water, rinse, dry fully, reinstall. Even if we are coming for a cleaning, fresh filters help.
3. Clear 18 inches around the outdoor unit. Shrubs, leaves, lawn furniture, kids toys. Vermont snow piles up fast against outdoor units in November.
4. Check the outdoor unit pad or feet. Settling or frost heave can tilt the unit, which strains refrigerant lines. If yours is visibly tilted, mention it during your cleaning visit.
5. Test the system in heat mode. Before peak cold (ideally before Halloween), run a 30-minute heat cycle. Confirm the indoor unit blows warm air and the outdoor unit runs. Catch any issue while there is still time to book repair work.
6. Check the condensate drain line. If the drain line runs outside through an unheated cavity, it will likely freeze at some point. Heat tape ($20 at any hardware store) wrapped around the exposed run prevents the freeze, which prevents the P5/condensate overflow errors common in Vermont.
7. Replace remote batteries. Dead remotes are the most annoying breakdown during a cold snap.
8. Set a thermostat schedule that does not include overnight setbacks. Heat pumps are more efficient maintaining a steady temperature than recovering from a setback. The savings from lowering the setpoint at night are negative.
What to do before the first hard freeze
Specifically before temperatures drop below 10°F:
- Confirm the outdoor unit is elevated above expected snowfall (or on a platform)
- Confirm no shrubs or wind-blocking structures are within 18 inches
- Confirm the indoor units have clean filters
- Confirm the condensate line has heat tape if it runs through cold areas
Vermont-specific considerations
Northeast Kingdom homes. You will see -20°F a few nights a year. Hyper-Heat units are rated for that. Standard mini-splits may not be. Know your model.
Lakeside homes. Lake-influenced humidity is at its highest in shoulder seasons. Biofilm buildup peaks in September. Booking a September cleaning makes the most impact here.
Wood stove or fireplace use. Wood smoke residue accelerates coil and filter loading. Clean the outdoor coil more often (twice a year is realistic).
Book your fall cleaning
Book in 60 seconds. September and October slots fill fastest in Burlington, South Burlington, Stowe, and Montpelier; book early.