Hartzell’s Heat & Air | Oklahoma HVAC Maintenance Calendar

The trick to an Oklahoma HVAC maintenance calendar: service the system the month BEFORE you lean on it.

Most people call me the week their AC quits in June or their furnace dies in December. By then it is an emergency. The fix is simple, and I have the data to prove the timing. Tune the AC in May, tune the heat in October, and you skip the worst of the breakdown season.

I went back through nearly a decade of my own work orders here in central Oklahoma and sorted every no-cooling and no-heat call by month. This is my real job history, not a national average. The pattern is so clean it tells you exactly when to schedule.

What the failure data says about timing

No-cooling calls ramp up in May, then nearly double in June. June is the peak, ahead of July and August. No-heat calls do the same thing six months later: they climb through October and November, then peak in December. Cooling problems are my single biggest repair category overall, about one in three repair calls across all those years.

	May	Jun	Oct	Nov	Dec
No cooling	25	47	2	2	0
No heat	0	0	7	7	13

That is the whole argument for a calendar. The failures cluster in the same months every year, so the maintenance should land just ahead of them.

The Oklahoma HVAC maintenance calendar, month by month

March and April (spring): Swap the air filter and start checking it monthly. Pollen and Oklahoma wind load a filter up fast in spring, and a clogged filter chokes airflow before the cooling season even starts. This is also a good time to clear leaves and grass off the outdoor unit.

May (tune the AC now): This is the most important date on the calendar. Get a full AC tune-up in May, before the June spike. The first long run of the summer is what exposes a weak capacitor, a low refrigerant charge, or a tired compressor. A May checkup catches that on a 75 degree afternoon instead of a 100 degree one.

June, July, August (summer): Change or clean the filter monthly while the system runs hard. Keep the outdoor coil clear of grass clippings and cottonwood. If you see water around the indoor unit, call me. A clogged condensate drain will shut a system down on the hottest day of the year, and it is one of the cheapest things to prevent.

September (shoulder season): Lighter load, fewer failures. Good month to fix anything you noticed limping through summer, before the parts and the schedule fill up.

October (tune the heat now): Same logic as May, flipped. Get the furnace or heat pump serviced in October, before the December no-heat peak. The first hard cold snap does to a furnace exactly what the first heat wave does to an AC. A fall tune-up checks ignition, the heat exchanger, and the blower while it is still warm enough to wait on a part.

November and December (winter): Keep changing the filter monthly. Heating runs pull just as much air as cooling. Listen for short cycling or weak airflow on the first cold mornings and call early, not after the system is fully down.

January and February: Deep winter. Replace the filter, keep the outdoor unit clear of ice and snow drift, and watch for the system running constantly to keep up. That is your early warning to book a spring tune before the rush.

Filters are the one thing you do yourself

Everything above runs on one habit: change the filter monthly during heavy-use months. A dirty filter is behind a surprising share of the no-cooling and no-heat calls I run. It is the cheapest insurance in the house. Set a phone reminder and you have already done half the job.

The plan version of all this

If you would rather not track the calendar yourself, that is what my maintenance plans are for. I schedule the spring AC tune and the fall heat tune for you, so the system gets checked the month before you lean on it, every year, without you remembering. Call and I will walk you through which plan fits your system.

Frequently asked questions

When should I get my AC tuned up in Oklahoma?

May, before the June failure spike. In my own service records, no-cooling calls ramp from 25 in May to 47 in June. A May tune-up catches a weak capacitor or low refrigerant before the first heat wave turns it into a no-cooling emergency.

When should I service my heating in Oklahoma?

October, before the December peak. My no-heat calls climb through October and November at 7 each, then peak at 13 in December. A fall tune-up checks ignition and the blower while it is still warm enough to wait on a part.

How often should I change my HVAC filter in central Oklahoma?

Monthly during heavy-use months, spring through summer and through winter. Oklahoma pollen and wind load a filter fast, and a clogged filter is behind a real share of the no-cooling and no-heat calls I run. It is the cheapest insurance in the house.

Why service my system before I actually need it?

Because the failures cluster. Cooling calls peak in June and heating calls peak in December every year, so a tune-up the month before, May for AC and October for heat, catches the weak part on a mild day instead of leaving you stuck on the worst one.

How do you know this timing and not just guess?

This is my own work order history, real jobs over nearly nine years in central Oklahoma, not a national stat. I am Dave Hartzell, Master HVAC, 45 years in the trade, 4.8 stars across 279 reviews.