The houses that make it to fifteen summers around here all have one thing going for them. Somebody looked at the system on a schedule instead of waiting for it to quit on a 99 degree afternoon. The real question is how often to service your AC when our cooling season runs close to six months, because the usual national answer was written for a much shorter one.
The honest interval for a house in this climate
Twice a year. Cooling in spring, heating in fall.
Run straight cooling with a gas furnace that barely works from December through February, and one thorough spring visit is defensible. You still have to book it, and handle filters in between. Skipping years is how a ten year old system starts behaving like a fifteen year old one.
Heat pumps get two visits, no wiggle room. More on that below.
The run hours behind the twice-a-year rule
San Antonio averages 122 days a year at or above 90 degrees, per National Weather Service climate normals. More than 80 land between June and August.
The U.S. Energy Information Administration notes that the West South Central census division, which includes Texas, generally logs the most cooling degree days in the country. Its residential survey found 95 percent of Texas homes use cooling equipment, against 89 percent nationally.
Equipment here piles up run hours at a rate national maintenance advice never accounted for.
ENERGY STAR is plain about timing: check the cooling system in the spring and the heating system in the fall, with annual pre-season check-ups on that split. ANSI/ACCA 4, the maintenance standard contractors build plans against, added a recommended minimum frequency per task in 2019, with room to tighten it based on how hard equipment runs.
What stretching the interval actually costs
Karen Fenaughty and Danny Parker at the Florida Solar Energy Center, part of the University of Central Florida, monitored 56 homes over four years to watch cooling performance decay in a hot, humid climate. Median degradation came in at 5.2 percent a year.
Compound that year over year and a system loses a serious share of its capacity well before it dies. Median system life in that study landed at 14 to 17 years, with coil fouling and charge problems the likely causes.
The gap between a well maintained system and a neglected one doesn’t announce itself. It shows up as a slightly longer run time every month, until one August the system never shuts off at all.
A tune-up you skipped for three years doesn’t come back as a tune-up. It comes back as a compressor.
Book the cooling visit in spring, not in July
Two things drive that timing, and habit isn’t either of them.
CPS Energy applies a peak capacity charge to residential usage above 600 kilowatt hours, June through September. Whatever efficiency your system gave up over the winter gets billed hardest in those four months. March is when you get that back cheaply.
Then there’s the calendar. By mid-July most of what we take is breakdown work. Maintenance falls in behind people sitting in 90 degree houses. Spring is when you get to pick the day.
What pulls your interval from twelve months down to six
Some houses can’t hold a twelve month interval no matter how new the equipment is. These come back early:
- The system is past ten years old with no service history.
- Two or more shedding pets live in the house.
- The driveway or the road out front is caliche or gravel.
- Heavy tree cover drops leaf litter and seed onto the condenser all season.
- The house runs two systems, which means two service clocks.
- Somebody has allergies and the house runs a high MERV filter.
- The system already needed one repair this cooling season.
- Remodeling or drywall work happened in the house this year.
Boerne and Spring Branch keep different clocks
Both sit in our northwest run. They don’t get the same service calendar.
Boerne and the new master-planned builds
Boerne carries two housing stories at once: a historic downtown core, and a wave of new master-planned construction ringing it.
Most of those big new homes run two systems. Two systems means two service visits on the calendar. The upstairs unit carries the heavier load, so it earns the tighter interval. New equipment also sits inside a manufacturer parts warranty, and those warranties exclude failures traced to neglected upkeep. The dated invoice is what protects it.
Downtown runs the other way. Retrofitted historic homes rarely have room for a deep media filter, so a one inch filter does the work, and it loads in weeks.
Spring Branch and the rural exurban lots
Spread out homes on open land, almost nothing shading the equipment. That outdoor unit takes sun all day and pulls air off a gravel drive and dry pasture.
Condenser coils foul faster out here than inside the city, which is why the fall visit stops being optional even on a straight cool system. Winter counts too. Robert Edmonson, a biologist and certified arborist with the Texas A&M Forest Service, notes that the density of Ashe junipers across Central Texas releases an enormous pollen load at once, from mid-December into March. Your blower still runs those months, so a January filter check belongs next to the fall visit.
Heat pumps run all year, so they get two visits
A heat pump is one machine doing both jobs, so its annual run hours land well above a cooling only system’s. Heat pumps need a technician at least once a year. Here, that phrase marks the floor.
There’s also hardware on a heat pump that simply can’t be tested in cooling mode. Checking it in October means finding the fault at 78 degrees outside instead of on the first cold night.
If you’d rather not track any of this, ask about a maintenance plan. The honest value of a plan structure is scheduling: it puts you on the calendar ahead of the season and keeps a dated service record.
What has to be true before you stretch the interval
Want twelve months between visits? These need to check out first:
- Filter type and depth. EPA notes manufacturers typically recommend replacement every 60 to 90 days. A one inch filter in a dusty house won’t make 60.
- Filter MERV rating. EPA points to MERV 13 or as high as your system’s fan and filter slot can actually handle, and a tighter filter needs changing more often.
- Condenser clearance. Open space around the outdoor unit, no shrubs or fence panels crowding it.
- Drain line condition. A slow primary drain in April is a ceiling stain in July.
- Charge history. A system that’s been topped off has a leak, and a leak sets its own interval.
- Airflow. ENERGY STAR puts efficiency loss from airflow problems at up to 15 percent, before anything actually breaks.
- Documentation. No invoices means no service history, and on equipment under warranty that becomes your problem.
- System age. Past twelve years, the visit becomes a condition report you’ll use to decide on replacement.
When more service isn’t the answer
Maintenance won’t rescue an undersized system or a failing compressor, and it won’t seal a leaking return. If your house can’t hold temperature on a normal afternoon, you need a diagnosis rather than a different interval. We walked through the usual suspects in why your AC isn’t cooling. Past that, our HVAC service contractor work in San Antonio starts with a full diagnosis and a plain English answer.
We’re family-owned, licensed in Texas as a Class A air conditioning and refrigeration contractor with the Combined endorsement under TACLA00102222C, EPA 608 certified, and BBB A+ rated. We’d rather tell you your system has four good years left than sell you one it doesn’t need. Repairs carry our 90-day warranty, and financing is available if replacement is the honest call.
Call or text 210-763-4698, Monday through Saturday, 7 a.m. to 7 p.m.