How do I get my air conditioner ready for summer?

Why test early, and why above 60°F?

Running an air conditioner when it is too cold outside can damage the compressor and gives a misleading result, because the system cannot build normal operating pressures. Wait for a day above roughly 60°F, then run it long enough to see real behavior.

Testing early is about the calendar as much as the equipment. Every HVAC company in the Des Moines metro gets slammed on the first stretch of 90-degree days. A unit that fails its April test gets fixed on your schedule; the same failure discovered in July puts you in a queue.

What should I do outside?

The outdoor condenser rejects your home's heat, and it cannot do that if it is smothered. Iowa gives it plenty to contend with — cottonwood seed in early summer, grass clippings, leaves, and whatever blew in over winter.

Outdoor unit prep

• Remove any winter cover completely before running the system
• Clear leaves, grass clippings, and cottonwood fluff from the fins and the base
• Cut back vegetation to leave at least two feet of clearance on all sides
• Gently rinse the coil fins from the inside out with a garden hose — never a pressure washer
• Check that the unit sits level; a settled pad stresses the refrigerant lines
• Look for damaged or missing insulation on the larger refrigerant line

What should I check inside?

Replace the filter first — starting the season with a clean one matters more than any other indoor item, because a restricted filter can freeze the evaporator coil outright.

Then check the condensate drain. Your AC pulls a surprising amount of water out of Iowa's humid summer air, and that water leaves through a drain line that clogs with algae and biofilm. A blocked line means water backing up into the pan and, in many homes, onto a ceiling or a furnace control board. Confirm it drains freely, and check that any float switch is functional.

Finally, switch the thermostat to cool, set it several degrees below room temperature, and confirm the system starts within a minute or two.

What does a good test look like?

Let it run 15 to 20 minutes, then check the air at a supply register. You are looking for a meaningful temperature drop between the return and the supply — typically somewhere around 15-20°F. Air that is only slightly cool signals low refrigerant charge, a dirty coil, or an airflow problem.

Also listen and look. Grinding, screeching, or repeated hard clicking at startup are worth investigating. So is ice on the refrigerant lines, water around the indoor unit, or a breaker that trips. If any of those show up, shut it down and call rather than running it — a system running while iced or low on charge can damage the compressor, which is the expensive part.