Here in the Midwest we had a pretty warm late summer/early fall, but it’s time to start thinking about putting your AC to bed for the cold months, so that it’s ready to perform at peak when it’s needed next year. And for that matter, it’s not a bad idea to get it done in conjunction with any furnace maintenance you might need headed into the winter.

Replace the Filter(s)

First of all, you want to replace your filter, so that your unit’s ready to go when it gets warm again. It’s not just a matter of health–though it is that. A clogged AC filter can reduce the efficiency of the unit by as much as 15%. And again, you may want to replace your filter at the same time as you replace your furnace filter. A properly functioning filter on either unit will help cut down on potentially harmful particulates in your indoor environment, and if you’re an allergy sufferer–particularly if you react badly to dust–you might want to consider replacing that filter a little more often even than recommended by the manufacturer. Like air conditioner efficiency, a clean filter will also make your furnace operate more efficiently by increasing the through-flow.

Clean Around the Condenser Coils

Cooling is performed through the expansion and contraction of coolant in the condenser coils. When these get covered with spider webs, dust bunnies, and particulate matter, it decreases the efficiency. There are how-to videos out there that will walk you through the process, and even specialty cleaning products which are very useful. For a central AC unit:

1. Cut power to the device at the breaker. THIS IS VERY IMPORTANT!
2. Remove the fan assembly.
3. Carefully remove the fan out of the way to expose the interior of the air conditioner.
4. Glove up to remove any debris that you can by hand (it’s possible sharp items may be down there.
5. Use a shop vac to remove smaller clutter.
6. Inspect the fins on your heat exchanger. They are quite delicate, and are easily bent or broken, so be gentle working around them. There are specialty tools that can help to straighten out problem areas where lots of fins have been bent or flattened that may be able to help some.
7. It’s very important to clean out any dust and debris that might have become embedded in the fins, and to clean them, you work from the inside out. As air gets sucked into the unit, it passes through the fins and pulls away accumulated heat. It is then blown by the fan through the top of the unit. Airborne materials therefore end up wedging themselves in the fins, reducing the heat-transferring capacity of the unit.
8. You can determine how clogged the fins are by shining a (preferably high intensity) flashlight through the fins from the inside out. It’s best to do this when it’s not super bright out, obviously. If you’ve got material caked on the fins, a clean is way overdue.
9. Using a commercial condenser cleaner (many pros prefer the foaming kinds), spray the foam liberally from the inside to flush the gunk back to the outside. It’s going to look a little like oven cleaner, but it’s nowhere near as noxious.
10. Let it sit for 10 minutes or more to let it do its thing.
11. Spray out the fins with your garden hose, but don’t use too much pressure, because you are dealing with somewhat delicate materials. Be thorough and take your time. It’s important to get all the foam and loosened materials out of there.
12. Once you’ve given the inside-out several thorough rinsings, rinse the outside as well.
13. You may wish to do another flashlight test just to see what your results are like.
14. Before you reinstall the fan assembly, get a look around. Are there any crimped or exposed wires? Is there any damage to the fan? If so, you might want to fix it, if you can, or have a professional in to get a look.
15. Reinstall the fan assembly and reconnect the breaker.

Have You Heard Any Unusual Noises Coming from the AC?

Any air conditioner makes some noise, of course, but if you’ve noticed that your AC is noisier than it used to be, it’s probably time to have a pro take a look. Same if you’re having to crank it to get the same results. In the case of noise, it’s possible that the fan has become damaged or misaligned, or it could be another problem. At any rate, it will be useful to a service person to know what might have happened at the time the trouble began. Did you have a power surge? Was there an electrical storm? Did you hit something with the lawn mower that might have smacked into the AC unit?

In the case of diminished operational efficiency, it’s likely that you may need to have the coolant topped up, or there’s trouble with the thermostat, but it’s also possible that it’s just time to replace the unit. On average, an AC unit will last about 10 years, depending on the climate, the frequency with which it is operated, the stress that is put on the system to cool the area (it’s best to have some excess cooling capacity), the general physical environment, and maintenance. It might just be time to replace it.

At any rate, if it’s time to put your AC to bed for the season, there are things you can do to help it operate better by yourself. But if you feel that you’d like to have someone come give it a look, the pros at Quality Heating will be more than happy to check it all out, replace the filters, give you their advice– and check your furnace, too. Quality Heating is located in Brookfield, and they’ve been installing and servicing AC and furnaces in the Milwaukee, Jefferson, Ozaukee, Waukesha, Racine, Sheboygan and Washington counties since 1961. They are also Southeast Wisconsin’s premier HVAC specialists. Give them a call. They have the expertise to keep your systems running efficiently, saving you time, money, and hassle in the long run.