How to Winterize a Central AC Unit
Winterizing your air conditioner is an important part of maintaining your HVAC system. If you’re not sure where to start, this guide on how to winterize a central AC unit explains how to prep the condenser so you can prevent damage to your outdoor unit and extend its longevity.
Supplies
Warm Water
Rope or Bungee Cords (for securing the cover)
Garden Hose
Screwdriver (if performing deep clean)
Air Conditioner Cover, Tarp or Plywood (to cover the unit)
Foam Pipe Insulation
Before winterizing your unit, check the warranty to make sure that performing maintenance won’t invalidate the warranty.
How to Winterize a Central Air Conditioner
Cut the Power
To avoid electrical hazards, it’s important to turn off your air conditioner and cut power to the unit before beginning with the winterization procedure.
- Step 1. Turn off the unit - Use your indoor thermostat to turn the air conditioner off.
- Step 2. Locate and examine the disconnect box - Next, go outside and locate the disconnect box on the wall behind the unit. Note if the box has a red lever on the outside; if it doesn’t, there should be a pull-out disconnect inside the box.
- Step 3. Cut power to the unit - For a pull-out disconnect, open the box and pull out the disconnect switch. Then, flip it over and stick it back in the box in the off position. If the box has a red lever, simply push down the lever: there’s no need to open the box.
Clean the Condenser
Although it’s fine to use the normal pressure from a garden hose to clean the air conditioner condenser exterior, don’t use power washers or high-pressure garden hose streams as these can damage the coils.
- Step 1. Clear away debris from around the condenser - Once power is cut to the air conditioning condenser, use a broom or gloved hands to remove leaves, branches, pine cones and other debris from around the unit.
- Step 2. Clean out the interior (if necessary) - Removing debris and cleaning the coils inside the AC condenser unit should be done once a year as part of routine air conditioner maintenance. If you still haven’t performed a deep clean, do so now.
- Step 3. Wash the exterior - Spray the AC condenser exterior with a garden hose to dislodge dirt and remove debris. Remember to use a normal pressure and to spray at an angle in order to avoid damaging the coils.
- Step 4. Dry the condenser unit - Use clean, soft cloths to dry the exterior and remove any remaining dirt or other debris.
Cover the Condenser and Insulate the Lines
Since covering the entire unit can trap in moisture and lead to rust, most manufacturers recommend only covering the top of the unit. Also, if the condenser is part of a heat pump system, don’t cover it since doing so can block the flow of air and damage the unit.
- Step 1. Cover the top - Use a tarp, AC cover or even a piece of plywood to cover the AC condenser unit. If using a tarp or cover, make sure the cover goes no more than 6 inches down the sides of the unit so as not to trap in moisture.
- Step 2. Secure the top - Once the cover is in place, secure it with rope or bungee cords. If using plywood, weigh it down with bricks, rocks or other heavy objects.
- Step 3. Inspect pipe and wiring insulation - Check the insulation on the pipes and wiring leading to the air conditioner condenser. Make sure the insulation on the lines isn’t missing or damaged.
- Step 4. Replace line insulation (if necessary) - If needed, replace the foam insulation surrounding the pipes and wires leading to the unit.