There is a point every fall in Southwest Michigan where you notice the air conditioner has not run in a week. That is the moment to close it down properly.
It takes fifteen minutes, costs nothing, and prevents the specific problems that show up in May when you try to start it again.
Quick answer: To shut down your AC for winter, cut power at the outdoor disconnect, rinse the condenser coil, think twice before covering the whole unit, switch the thermostat over to heat and change the filter. Those five steps are the safe way to shut down the system without inviting rust or rodents by spring.
Setting the thermostat to Off stops the system from calling for cooling. It does not cut power to the outdoor unit.
Most central air conditioners have a small box on the exterior wall within a few feet of the condenser, containing either a pull-out block or a switch. Cutting power there prevents the unit from trying to start on an unseasonably warm December day with cold compressor oil, and protects it during winter power surges.
One important exception. If you have a heat pump, leave it powered. A heat pump is your heating system through fall and winter, and it needs power to the outdoor unit. Not sure which you have? Check the thermostat — a heat pump thermostat has an Emergency Heat or Aux Heat setting. A straight air conditioner does not. More on how they run in cold weather in our guide to heat pumps in Michigan winters.
Over a Michigan summer the outdoor coil collects cottonwood, grass clippings, dust and whatever the mower threw at it.
With the power off, rinse the coil with a garden hose at normal pressure, spraying through the fins. Do not use a pressure washer. It flattens the aluminum fins and permanently reduces airflow through the coil, which is one of the quieter causes behind an AC not cooling the following summer.
Clear leaves out of the base of the cabinet and cut back anything that grew in close over the summer. Two feet of clearance on all sides.
This is where most homeowners get bad advice.
A full wrap-around cover is usually a mistake. It traps moisture against the coil, which accelerates corrosion, and it turns the cabinet into an appealing winter home for mice, which then chew the wiring. Come spring you have a rusted coil and a rodent problem.
Condensers are built to sit outside year-round. Snow and cold do not hurt them.
What is worth doing is a breathable top cover or a piece of plywood weighted over the top. That keeps falling icicles, roof ice and heavy debris off the fan and coil while air still moves through the sides. If your unit sits under a roofline that sheds ice, this is not optional — a single sheet of ice off a garage roof destroys a fan blade.
Move it from Cool to Heat and set a schedule that fits a Michigan fall, where a 76-degree afternoon drops into the low 40s overnight. This is also the moment to replace the batteries. Our guide to fall thermostat settings covers the shoulder-season schedule in detail, and it is the heating counterpart to the best thermostat settings for summer.
The filter serves both systems. One that ran all summer is loaded, and starting the heating season behind it is a bad idea.
The size is printed on the frame of the one you pull out, and you can order replacements online so a spare is on the shelf.
The evaporator coil sits inside the air handler or above the furnace, and it is not a homeowner job. It is delicate, awkward to reach, and the drain pan and condensate line underneath need to be clear before heating season. On a high-efficiency furnace sharing that drain, a partial blockage will shut the system down.
It is a standard part of AC maintenance and worth handling while a technician is already there for the furnace.
Wrapping the unit in plastic. Traps moisture, invites rodents, causes corrosion.
Leaving the disconnect on all winter. Risks a cold-start compressor event on a warm day.
Piling snow against the cabinet. When shoveling or blowing snow, aim it elsewhere.
Forgetting you turned it off. Every spring someone calls about an AC that will not start and the answer is the disconnect they pulled in October. Set a reminder for April.
For over 50 years J&J has handled seasonal changeovers across Battle Creek, Marshall and the surrounding towns. It pairs naturally with a fall furnace tune-up, so both systems get handled in one visit.
A full cover usually does more harm than good. A breathable top cover or weighted board is worth it where ice or debris can fall on the unit. Otherwise the equipment is fine uncovered.
Most likely nothing. The risk is a warm winter day triggering a cooling call and starting the compressor with cold oil, which causes wear. It is cheap insurance, not an emergency.
No. A heat pump provides your heating, so it keeps running and keeps power to the outdoor unit through the entire cold season.
If you would rather we shut down and check your AC before winter, J&J can handle it during a fall visit.
Schedule service online or get in touch at (269) 965-1627 today! Prefer to pick a time yourself? Book your visit online.
9000 M-66 South • East Leroy, MI 49051
(269) 965-1627
Monday - Friday: 8:00am - 5:00pm
