DIY: Get Your AC Ready for Summer’s Hottest Months

Getting the air conditioning all prepped and serviced will make the rest of summer easy, enjoyable, and cool. antoniodiaz/Shutterstock

A warm breeze signals summer—and the time for a quick DIY air conditioning prep and service.

Experiencing the bliss of stepping into a cool room after being out in the sun starts with a clean air conditioning filter. If you changed it out as part of your fall shutdown and haven’t run it since—if you have a separate furnace system for winter months—you’re probably good. However, this is still a good time to check your supply of additional filters, which should be changed out at least every three months, or every two months if you have pets, and the type of filters you’ve been buying.

Filters have either MERV (maximum efficiency reporting value) or FPR (filter performance rating) ratings. The higher the number, the smaller particles it catches (such as the size of sneeze droplets), but the tighter weave necessary to catch these particles may obstruct the airflow and can strain the motor. When in doubt, check with the manufacturer or your AC installer, but don’t let them sell you a summer service that you can, in most cases, do yourself by reading on.

HEPA (high-efficiency particulate air) offers the best filtration, which is why they’re used in hospitals, but most home air conditioning units can’t handle the added resistance to airflow. If you have reusable filters, rinse them off in accordance with the manufacturer’s instructions, allow them to dry, and reinstall them.

Summer is the time to trim back any landscaping that might obstruct airflow to your outdoor condenser unit. Ned Snowman/Shutterstock

Clean Condenser, Happy Condenser

Turn off all breakers to both the interior and exterior portions of the system, and step outside. If you covered the outdoor condenser unit with a winter cover or tarp, good job. If you didn’t, order a cover now for this coming fall. Clean off any leaves, branches, or other outdoor debris stuck in the unit.

This is also the time to trim back any landscaping that might obstruct airflow. If you find dirt or debris in the large fan visible underneath its protective cage at the top of the unit, chances are that grit and grime have gotten inside the unit too, clogging the coils.

Double-check that all power to the system is off, then unscrew the side panels. Pull them away from the unit, then lift off the top. You may want to have help, as the fan is attached to the top, making it heavy. Be sure to not pull on any of the fan wires while setting this portion aside. Working from the outside of the unit, gently clean the coils with a refrigerator coil brush or the soft brush attachment on a vacuum cleaner, and we mean gently! If any of the delicate coil fins get bent, straighten them with a fin comb made specifically for this purpose.

Next, vacuum the inside. If it’s still dirty, you can spray on a commercial air conditioning coil cleaner from the inside, being diligent to keep it away from any electrical components and the fan itself. Be sure to wear gloves and eye protection.

Clean the fan with a rag or vacuum cleaner soft attachment, and tighten down any mounting bolts that may have become loose. Check the fan for motor oil ports, if it has them, and spray in WD-40 or use a few drops of a lightweight oil.

Don’t go inside just yet. Check the insulation on the coolant lines—the “pipes” that connect the outdoor condenser to the indoor air handler. Damage can be easily repaired or replaced with foam insulation tape, wrapped in a spiral fashion, or via cut-to-size foam insulation sleeves.

Air condenser units can be vacuumed out and cleaned with a soft cloth.DmyTo/Shutterstock

Ready, Set, Test

Note: If you used coil cleaner, which is usually hosed off, allow the outdoor condenser unit to thoroughly dry first.

Turn the breakers back on, set the thermostat to “off,” and power up the unit. Switch it to “cool” for a short test run to make sure it’s functioning properly. If there’s a readily apparent mechanical problem, shut things down immediately. You’ll need to fix it if doing so is in your skillset (in which case you’re probably not reading this article) or call a technician. Call right away, as technician schedules quickly fill up when that first heatwave rolls around.

If the unit is running fine but seems to be cooling unevenly, make sure all the vents are properly set and clean. You would be surprised how many tech calls occur because someone forgot that they had closed off a vent or that they set some vents wide open, stealing the air from rooms farther along the duct path.

As for dirty vents, in most cases, they can simply be wiped down with a clean rag or a microfiber cloth. If the vents are caked with dust, remove them, wash them in warm soapy water, allow them to dry, and reinstall them. Don’t forget to change your filter in 60 to 90 days to continue to enjoy optimal cooling with lower energy costs and a longer air conditioner lifespan.

Constant Comfort

A revolutionary upgrade to the traditional wall and window units yet not central air either, ductless mini-splits are their own species in the AC animal kingdom.

Filters First

In addition to controlling temps, these units function as air filters. Clean the easily removable and reusable filter every four to six weeks. Homes with smokers, pets, and so forth may want to consider an additional filter that’s attached to the existing one.

Outdoor Compressor

As with a whole house unit, cover the unit if it isn’t being used in winter and make sure that the area around the unit is free of leaves, dirt, and other debris. The outdoor heat pump can be rinsed down with a garden hose, but be sure to turn off all power first!

Set and Forget

Inverter-driven compressor technology allows for precise control of refrigerant through the system, functioning best when set to a particular temperature and then left alone. Regularly fiddling with the temperature setting can cause components to fail prematurely.