Keep it running5 min readOctober 6, 2026
Taking care of the outdoor unit: clearance, cottonwood, and a gentle hose
Keep two feet clear on every side of the outdoor unit and five feet above it. Shut the power off at the disconnect, then rinse the coil from the top down with a garden hose on a gentle setting, twice a summer and after the cottonwood drops in late spring. Never use a pressure washer, never bend the fins, and never set anything on top of the fan.
What the condenser is doing
The outdoor unit takes the heat the indoor coil absorbed from your house and dumps it into the yard. Its fan pulls outside air through the aluminum fins around the sides and blows it out the top. Anything that blocks those fins, from a hedge to a layer of fuzz, raises the pressure the compressor works against, which means a higher bill, less cooling and a shorter compressor life. On a 105-degree afternoon the margin is thin.
Clearance
Two feet on all sides, five feet overhead, and nothing leaning on it. Trim shrubs back, keep mulch and soil below the base of the cabinet, and move the grill. If a fence or wall is closer than two feet on more than one side, the unit is recirculating its own hot exhaust, and the fix is either moving the fence panel or, in a replacement, relocating the unit.
Mowing is the other repeat offender. Grass clippings blow straight into the fins. Mow with the discharge pointed away from the unit, or shut the unit off and rinse it after.
Rinsing the coil
Do this in May after the cottonwood seed has fallen and again in July.
- 1Turn the system off at the thermostat, then pull the disconnect at the box on the wall next to the unit (or flip the condenser breaker).
- 2Clear leaves and debris from around the base by hand.
- 3With a garden hose on a gentle spray, rinse the fins from the top down, working around all sides. Spray straight at the fins, not at an angle, so you do not bend them.
- 4If the fins are coated in fuzz, spray a foaming coil cleaner from the hardware store first, wait as the label says, and rinse.
- 5Let it drip for ten minutes, restore the disconnect, then turn the system back on.
What not to do
A pressure washer flattens fins in one pass and can push water into the fan motor. A covered unit in winter traps moisture and invites rodents; a plywood square on top to keep leaves out of the fan is fine, a full cover is not. And a unit that is out of level because the pad settled into the blackland clay stresses the compressor mounts and the copper lines, so if yours leans, have it re-leveled.
Watch it done
Questions on this
Do the misting kits that cool the condenser work?
They lower the air temperature at the coil a little and they leave mineral scale on the fins in our hard water, which is worse over a few summers than the gain. Skip them.
Should the unit be in the shade?
Shade helps marginally. Airflow matters far more, so never trade clearance for shade by planting close to it.