Skipping one simple HVAC maintenance chore can leave even a nearly new outdoor unit surprisingly clogged.

One homeowner's before-and-after photos served as a reminder that a 15-minute cleanup can protect an expensive piece of equipment and keep it running efficiently.

Here's what to know

After finding their outdoor unit in bad shape, a homeowner wrote that a once-a-year cleaning was well worth the small effort.

"Ideally, you should be doing this annually. It's extremely easy to do and all it takes is 15 minutes," they wrote.

What caught the poster off guard, they said, was seeing that much buildup on a system that had been installed in late 2024.

"I'm surprised mine was this bad as its a brand new unit that was installed in late 2024 so I skipped cleaning it last year," they added, later sharing an after photo in the comments.

For homeowners looking beyond maintenance alone, upgrading your heating and cooling system is also one of the best ways to save money on utility bills and protect yourself against rising energy prices. Palmetto can help homeowners understand their HVAC options and slash their energy bills with new, efficient HVAC systems and heat pumps, and its Comfort Plan network can connect you with vetted installers.

More background

Heating and cooling are among the biggest expenses on many utility bills, so even small efficiency losses can add up quickly.

There is no universal answer on timing.

In the comments, one reader asked whether the cleaning was better done ahead of cooling season or once peak use was over.

"You can realistically do it whenever," the original poster replied. "Some will argue that spring is best before it's about to be used for the season. Others will argue that fall is best to get all the crap off so it's not rotting on the coil all fall and winter. I like to do it in fall because it's likely not to get dirty while not being used."

The replies also suggested that location and home setup affect timing.

One commenter recommended cleaning "early in the season, late spring, after the heavy pollination period is done," and another noted that an all-electric household keeps the system running year-round.

What can be done?

Add an outdoor unit check to your yearly maintenance list.

Another practical point was cleaner strength. Recommending Nu-Brite by Nu-Calgon, the original poster warned: "Its very strong and will irritate your skin so wear eye protection and gloves when you use it."

If you're unsure, bringing in a professional may be the safer move.

Maintenance helps, but an older or inefficient system may still be costing you more than it should. Palmetto's Comfort Plan can help you explore efficient heating and cooling upgrades, and if you're not ready to spend upfront, the plan includes $0-down options that can lower your heating and cooling costs by up to 50%. It also includes 12 years of free maintenance.

Homeowners can also pair solar panels with electric appliances, such as efficient HVACs, to drive utility costs even lower. EnergySage makes it easy to find the best solar system and installer for your home and budget, saving you up to $10,000 on installations.

Where can I learn more?

Skipping an outdoor-unit cleaning isn't the only HVAC habit that can hurt performance.

• An HVAC technician warned that vacuuming disposable HVAC filters can damage them and reduce performance.

• A home maintenance expert urged homeowners to clean an air conditioning unit.

• An HVAC specialist said closing too many vents can strain airflow and raise bills.

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