Every spring I get a wave of calls in late June from people whose AC just quit. Almost every one of them is preventable with a 20-minute pre-season check in April or May. Here's the checklist I give my own customers — the half they can do themselves, and the half I should handle.
What you can do yourself (20 minutes, no special tools)
1. Replace the air filter (5 min)
The single highest-impact maintenance item. Restricted airflow from a clogged filter strangles the blower, makes the coil ice up, and causes the compressor to overheat. Find your filter slot (usually the return-air grille on a wall or the air-handler closet door), pull the old one, drop in a new one, write the date on the new filter with a Sharpie. Most South Bay homes need a new filter every 60-90 days during high-AC season.
If you're using a 1" filter, MERV-8 to MERV-11 is the sweet spot for airflow vs. filtration. Don't put a MERV-13 in a 1" slot — the pressure drop is too high.
2. Hose down the outdoor condenser (5 min)
Cut the power at the disconnect first (the gray box on the wall near the condenser). Then garden hose, gentle stream, top down. Do NOT use a power washer — you'll bend the fins. The goal is to rinse off the layer of dust, eucalyptus, and (in beach cities) salt that's accumulated on the coil since fall. Restored airflow can recover 10-15% of efficiency.
3. Clear vegetation (5 min)
The condenser needs at least 2 feet of clear space on all sides for proper airflow. Trim back any plants, shrubs, or fence sections that have crept into that zone since last fall. Pay particular attention to the top — overhanging tree branches drop leaves directly onto the coil.
4. Check the thermostat batteries (2 min)
If your thermostat takes batteries (most non-Wi-Fi models do), swap them now. A weak battery in late August will give you intermittent cooling that you'll mistakenly diagnose as a system problem.
5. Listen to the system on first run (3 min)
Set your thermostat to cool, drop the temp 5°F below room temp, and walk through the house. You're listening for: any clicking that doesn't stop, any banging or rattling that's new since last year, any squealing from the indoor blower (that's a bad belt or motor bearings). Note anything off.
What you should leave to a tech with a manifold and a multimeter
1. Refrigerant charge check
This is the one that nobody can DIY. A proper refrigerant charge check requires gauges, a thermometer, the manufacturer's superheat/subcooling charts for your specific system, and the ability to interpret all three. Refrigerant level affects efficiency dramatically — a system 15% undercharged uses 20-30% more electricity. Most South Bay systems lose 5-8% per year through micro-leaks; after 10 years, you're significantly low.
2. Capacitor and contactor electrical readings
The dual-run capacitor degrades gradually before it fails. A multimeter reading the microfarads tells you whether you're at 95% of spec (fine) or 78% (replace before it fails on a 95°F day). I do this on every tune-up; a homeowner generally can't.
3. Electrical tightening
The lugs on the contactor and the wire nuts at the disconnect work loose over time. A loose lug develops resistance, gets hot, eventually pits and arcs. The most common cause of compressor short-circuit is a loose contactor lug that arcs and welds itself shut. Costs $0 to tighten, $1,800 to replace the compressor.
4. Drain line clearing
The condensate drain line clogs with algae over the summer. When it does, your drain pan overflows. In a Hollywood Riviera or Manhattan Beach home with the air handler in the attic, that overflow drips through the ceiling and ruins drywall. A 5-minute wet-vac clear before the season starts prevents thousands in damage.
What a tune-up actually costs
I charge:
- $129 for a single-system tune-up (AC or heat side)
- $199 for both at the same visit
- Free if you've had a system from me installed in the last 12 months
The visit takes 45-75 minutes per system. You get a written summary of what was found, what was tightened or cleaned, and any recommendations — with no pressure to act on them.
When to schedule
For AC tune-ups: book in April or May. Definitely before the first 90°F day, which usually arrives around Memorial Day. Schedule fills up fast in late June when everyone realizes their AC isn't keeping up.
For heat tune-ups: book in October. Same logic, opposite season.
To get on the calendar this spring, call (866) 982-3652. Most weeks I have a couple of slots open inside two days.
Have HVAC questions? Call (866) 982-3652 or use the contact form. — Emilio Solano