In Columbia, your air conditioner may run for hours a day from May through September — and the hottest week of the year is the worst time to find out something's wrong. A few simple checks in spring, plus a professional tune-up, go a long way. Here's what you can safely do yourself and what to leave to a technician.

Test your cooling before the heat arrives

Switch to cooling on a warm spring day and make sure the system starts, air comes out of the vents and the house cools down. Set a schedule that keeps your household comfortable — there's no single "right" summer temperature. Thinking about a smart thermostat? Make sure it's compatible with your system's wiring and staging first.

Check your filter

Your system runs far more in summer, so the filter loads up faster. Check it regularly and replace or clean it according to the equipment and filter instructions, using the correct size. A more restrictive filter isn't automatically better for your system.

Keep air moving

Make sure supply registers and return grilles are open and not blocked by furniture, rugs or curtains. If one room is always hotter than the rest, the cause may be ductwork, insulation or airflow — worth having a technician look rather than guessing.

Clear around the outdoor unit

Remove leaves, grass clippings and overgrown plants from around the outside of the condenser so it can breathe. Keep the cabinet closed, and don't reach inside, straighten fins, spray chemical cleaners or pressure-wash the unit — coil cleaning is a job for a technician.

Book a spring tune-up

A qualified technician checks controls, electrical connections, the condensate drain, coils, airflow and refrigerant performance based on your equipment's requirements. It's the best way to catch a weak capacitor or clogged drain line before it quits in July. Refrigerant work requires an EPA Section 608-certified technician.

On Call's HVAC Maintenance plan puts a spring cooling tune-up and a fall heating tune-up on the calendar for you.

Warning signs to act on

  • Ice on the lines or indoor coil: turn cooling off. Don't chip it or use heat.

  • Water near the indoor unit or electrical equipment: stay clear and call us.

  • Smoke, arcing or a burning smell: get everyone out and call 911.

  • A breaker that keeps tripping: don't keep resetting it.

  • Dangerous indoor heat: move elderly family members, infants and pets somewhere cool, and tell us when you call.

Your summer checklist

  • Test cooling on a warm spring day.

  • Check or replace the filter.

  • Open and clear all vents and returns.

  • Clear debris from around the outdoor unit.

  • Schedule a professional tune-up.

On Call's NATE-certified technicians have kept Midlands homes cool since 2011. Our residential diagnostic fee is $89, waived when you go ahead with the repair, and you'll get a firm price before any work begins — plus in-person help with financing if you need it. Call (803) 781-4357, request service online or learn more about AC repair.