Air conditioner maintenance for homeowners

Summer is officially here, and the warm weather we've had over the last couple of weekends has given homeowners with air conditioners a chance to make sure their systems were still operating properly. I've recently heard from numerous friends and family about air conditioners that weren't working properly. If your air conditioner isn't cooling your home the way you expect it to, check on these simple maintenance items before calling out a professional to service your equipment.

Oh, and even if your system is working properly, check these things regular. This is important stuff.

The Air Filter

Dirty air filter

The single most important thing for homeowners to maintain is the air filter, and by "maintain" I mean "change religiously". On most Minnesota homes, the air filter is also known as the furnace filter. If it's one of those super-cheap single-ply 1" filters, it should be changed at least once per month.  Even better yet would be to use a better filter. According to Bruce Strandberg at BWS Heating & Air, cheap filters let a lot of small particulates through. These small particulates can accumulate on the underside of the evaporator coil, and even on the underside of secondary heat exchangers in high-efficiency furnaces, where they restrict airflow, reducing system efficiency.

Mid-grade pleated 1" filters have more surface area, so don't need to be changed as frequently, but most heating contractors still recommend changing them monthly. That's not bad advice, but it's probably more often than needed. These pleated filters are designed to be changed at least once every 90 days. My advice is to buy a big box of them, keep them by your furnace, and set a calendar alert every 60 – 90 days reminding you to change your filter. If your filter is nasty when you change it, do it more often.

High-grade super-duper ultra-filtration-smation filters are fine to use if they're changed religiously, but they're not as forgiving as other filters, meaning they get clogged more quickly, which causes problems with equipment much faster. Use these filters at your own risk.

For filters thicker than 1", take the filter manufacturer's recommendation for changing and cut the number in half to be safe. It might cost a little more in filters, but this is nothing compared to repair costs.

The Condensing Coil

This is the one that really gets forgotten about. The compressor and condensing coil are the parts that sit outside the home, preferably on the side of your yard where the noise isn't too obnoxious. To help dissipate the heat that gets removed from the home, a big fan pulls outdoor air over the condensing coils.

For the condensing coil to work properly, it needs plenty of airflow. The condensing coil should not be obstructed by other nearby units, house walls, plants, weeds, flowers, decorative shrouds, decks, etc. All of these things will hamper airflow.

Condensing coils also need to be cleaned regularly. When they operate, the fans suck air in on all of the open sides. This tends to pull in debris such as dirt, grass clippings, dryer lint, cottonwood seeds, and everything else in the air… except for love. Inspect all sides of your outdoor unit and clean the coils off annually, or as needed.

Dirty AC coil

If your air conditioner still isn't working properly after checking these things, check out my blog post from last year, How to Inspect Your Own House, Part 9: The Air Conditioner.  This post gets a little bit more detailed and involves some troubleshooting steps that homeowners can try.

If you notice ice on your unit either inside the house or outside and you've already checked everything listed in the post linked to above, it's time to call in a professional. Just be sure to contact someone you know and trust. If you don't have someone, get a referral from a friend or neighbor. If you don't have that, check reviews online before hiring. Also, beware of cheap AC tune-ups.

Author: Reuben Saltzman, Structure Tech Home Inspections


Written By

Reuben is a second-generation home inspector with a passion for his work. He grew up remodeling homes and learning about carpentry since he was old enough to hold a hammer. Reuben grew up thinking he was going to be a school teacher because he enjoyed teaching others so much. In a sense, that’s a lot of what home inspections are about, so Reuben truly does what he loves. Sharlene has worked with Structure Tech since 2000 and Reuben has been contributing to her blog since 2008.

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