Do outdoor condenser coils really need regular cleaning?
The outdoor condenser coil of your air conditioner performs a tremendous job here in Texas. It takes the heat collected from your home and sends it into the hot outdoor air. To get rid of the collected heat, your outdoor condenser coil has to move a lot of air. If the coil is dirty or if plants or other objects are too close to the conditioner unit, the fan in the outdoor coil can't move as much air as required for good performance and efficiency. This raises your electricity cost for air conditioning and may shorten the life of the outdoor condensing unit
Most condenser coils are loaded with pollen and dust even when you can't see it; in my case it was obvious. The longest a condenser should go without cleaning is 2 years, depending on how much it operates during the summer. If your cooling season is 4 months or more, annual cleaning is an excellent idea. These photos show over 8 years to accumulation.
Start by ensuring that the power to the unit is off, then remove any visible grass and lint from the fins and/or louvers with an old hairbrush or whisk broom or in my case a shop vac. The idea was not to force the debris farther into the coil. Then put on a pair of protective gloves and spray an outdoor coil cleaner into the coil. Wait five or ten minutes and flush the coil with a gentle water spray.
If more aggressive cleaning is needed an old hairbrush works well for brushing surface dirt and lint off the fins. Brush in the same direction as the slots between the fins so the bristles go between the fins. Wear a dust mask to avoid breathing the dust. Then, direct a light spray from a garden hose at the coil's interior through the fan opening in the top of the unit. Use a gentle spray because a strong spray could bend the aluminum fins.