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A guide to air conditioner maintenance

Maintaining your AC will help you stay cool (and save energy) all summer.


Air conditioning can be your best friend on a hot summer’s day. But to truly get the most out of it – and save energy – it’s smart to make maintenance a priority. Thankfully, a little bit of work each season can help you keep cool all summer long.

Here’s how a qualified HVAC professional can help, plus some extra DIY tips for getting the most out of your AC.

Start with a visual inspection

While comprehensive AC maintenance is best left to the pros, you can still do your own visual inspection.

If you have a room air conditioner, you can check the seal between the unit’s metal case and the window frame to ensure it’s intact at the start of the season. Moisture can damage the seal, causing cool air to leak out of your windows and your unit to run less efficiently.

With outdoor central air units, check for debris, such as leaves or dirt, and whether the internal fins on the fan look straight. If you do spot a lot of debris, avoid disassembling the unit yourself, tempting as it may be to try. A common mistake is also to use a pressure washer, which can damage the unit. If it’s time for a cleaning, call on a professional.

A deep clean from the pros

As with your other appliances, air conditioners get dirty. The filters, coils and fins all require regular maintenance so the whole unit can run efficiently. Here are some basic steps a professional can address.

Cleaning or replacing filters: Clogged or dirty internal filters (in the indoor part of the unit, the same as the furnace filter) block air flow and reduce efficiency. If you think this doesn’t make a big difference, it’s time to reconsider. Replacing a dirty filter can cut your unit’s energy consumption by as much as 15 percent.1

Cleaning coils: Evaporator coils cool the warm, humid air from inside your home before recirculating cooler air inside again. Clean filters help keep these coils clean, but over time they’ll still collect dirt. A professional can inspect the evaporator coil and clean it as necessary.



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Cleaning the drain: When humidity in the air hits the cool evaporator coil, it creates condensation. And just like the sides of a glass of ice water dripping onto a coaster underneath, an evaporator drain is there to catch the liquid from the coils. Mold and algae can build up (and potentially block the drain), so it’s important to keep it clean to keep your unit running in peak condition. A plugged drain may also cause flooding. A qualified professional can ensure this drain line is clear.

Good habits, inside and out

Along with leaning on the pros to keep your AC in top shape, there are also DIY tasks you can take on.

Indoors: First, draw your blinds or curtains on hot sunny days to keep your home cooler. Check the seals around windows and doors. If you find that outdoor air is making its way in, apply weather stripping or caulking outside. This low-cost move will also help you save on heating in the winter. Ensure your ductwork is properly sealed as well. Finally, consider installing a smart thermostat – this will help keep your home cool more effectively during different times of the day, without you having to think about it.

Outdoors: Trees and shrubbery near your unit are a common design choice to hide it from view and shade it from the sun, but be sure nearby plants aren’t interrupting air flow. Trimming foliage back at least two feet should do the trick. While you’re outside, check to make sure your dryer vent is angled away from your AC unit. Lint from dryer exhaust can cause dirt to build up inside your unit.

Don’t forget seasonal wrap-up

When the weather turns cooler, switching off your AC isn’t quite the end of the story. For both room air conditioners and outdoor units, cover them up for the winter to protect them from dust and debris (just be sure to remove the covers in the spring). This simple step will reduce the chances of your AC not working properly the next time a heat wave comes along.

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