Pre-Summer Commercial HVAC Checklist:
10 Things Bay Area Businesses Must Do Before June
Your commercial AC system will fail on the hottest day of the year — unless you prepare it now. Here’s the exact 10-point checklist we use when preparing Bay Area commercial buildings for summer, and what each step actually prevents.
Every summer, we get emergency calls from Bay Area businesses whose AC systems failed on the first 90°F+ day. In nearly every case, the failure was preventable. A capacitor that was weak in April dies in July. A dirty condenser coil that barely kept up in May can’t reject heat when ambient temperatures hit 95°F. A refrigerant leak that was “minor” in spring becomes a compressor-killing problem by August.
Here’s the 10-point pre-summer checklist we follow for commercial buildings across San Jose, Sunnyvale, Mountain View, and Redwood City. Each step includes what it prevents and what it costs if you skip it.
The best time to schedule pre-summer maintenance is March through early May. By June, every HVAC contractor in the Bay Area is booked with emergency calls. You’ll pay premium pricing and wait days instead of hours.
Clean the Condenser Coils
What it is: The outdoor unit (condenser) rejects heat from your building to the outside air. When the coils are caked with dirt, dust, pollen, cottonwood seeds, or kitchen grease, the unit can’t reject heat efficiently. Compressor head pressure rises, energy consumption increases 20–40%, and the system can’t keep up on hot days.
What we do: Chemical wash of all condenser coils, straighten bent fins (improves airflow 15–25%), clear debris from around the unit. For restaurants: degrease with commercial coil cleaner to remove kitchen exhaust residue.
If you skip it: 20–40% higher energy bills all summer. On 95°F+ days, the system can’t reach setpoint. Compressor runs nonstop, reducing lifespan by 30–50%. Compressor replacement: $2,500–$8,000.
Bay Area Specifics
Buildings near highways (101, 280, 880) accumulate more particulate. Buildings near Half Moon Bay and coastal cities get salt corrosion on coils. Both need more aggressive cleaning schedules — every 3 months instead of 6.
Check Refrigerant Charge Levels
What it is: Refrigerant is the blood of your AC system. Too little = poor cooling and compressor damage. Too much = high head pressure and efficiency loss. Both conditions are invisible until the system fails under peak load.
What we do: Measure superheat and subcooling at the outdoor unit. Compare to manufacturer specs. If low, perform electronic leak detection before adding refrigerant — adding refrigerant to a leaking system is a waste of money.
If you skip it: A 10% undercharge reduces efficiency by 20%. A slow leak that was manageable at 75°F ambient becomes a complete failure at 95°F when the system needs full capacity. Emergency refrigerant refill in July: $150–$300/lb for R-410A, plus $200+ emergency surcharge. That’s 3–5x the cost of finding and fixing the leak in spring.
Test & Replace Capacitors
What it is: Capacitors are like batteries that give the compressor and fan motors the initial jolt to start. They weaken with age and heat exposure. A weak capacitor in spring becomes a dead capacitor on the first 90°F day — this is the single most common cause of “AC died on the hottest day.”
What we do: Measure microfarad rating of every capacitor in the system. Daikin, Carrier, and Trane specs allow ±6% tolerance. If a capacitor is more than 10% below rated value, we replace it proactively. Cost: $80–$200 per capacitor (part + labor).
If you skip it: When a run capacitor fails, the compressor can’t start. You have zero cooling. Emergency service call in peak season: $300–$500 for the same $80 capacitor that could have been replaced during a tune-up. Plus lost revenue and employee productivity during the wait.
Capacitors over 5 years old should be replaced proactively during pre-summer service — even if they test within spec. The cost difference between proactive and emergency replacement is 3–5x, and the downtime cost for a commercial building dwarfs the part cost.
Replace All Air Filters
What it is: Filters protect the evaporator coil and indoor air quality. A clogged filter restricts airflow, drops evaporator pressure, and can freeze the coil. In a commercial building, frozen coils mean water damage to ceilings when ice melts.
What we do: Replace all return air filters with correct MERV-rated replacements. MERV 8 for standard commercial, MERV 13 for medical and clean environments. Note filter sizes on the maintenance record so reorders are exact.
If you skip it: Evaporator coil freezes, melts, water drips through ceiling tiles ($500–$3,000 in water damage). Static pressure rises, blower motor works harder, uses more energy, and fails sooner. Motor replacement: $500–$1,500.
The Rest of the Professional Checklist
5. Inspect Belts & Bearings
V-belts on belt-driven blowers stretch and crack over winter. A belt that snaps mid-summer means zero airflow until a tech arrives. We check tension, alignment, and surface condition. Replacement during tune-up: $100–$200. Emergency replacement: $300–$500+ with wait time.
6. Test Electrical Connections
Thermal cycling (hot days, cool nights) loosens electrical connections over time. Loose connections arc, overheat, and eventually fail. We torque all connections per manufacturer specs and check contactor points for pitting. A pitted contactor that chatters will weld shut under peak load — locking the compressor on and potentially burning it out.
7. Clear Condensate Drains
Biofilm and algae grow in condensate lines during spring. By July, the line is clogged. Water backs up, overflows the drain pan, and drips through the ceiling. We flush lines with compressed nitrogen and treat with biocide tablets. Cost to clear: $100–$200. Cost of water damage: $1,000–$10,000+.
8. Verify Thermostat & Controls
Programmable thermostats and BAS schedules need updating for summer occupancy patterns. We verify setpoints, schedules, and deadband settings. A thermostat that’s 3°F off calibration means the system works 15–20% harder than necessary all summer.
9. Check Economizer Operation
Economizers use cool outdoor air to supplement or replace mechanical cooling. In the Bay Area, mornings are often 55–65°F — perfect for economizer operation. But if the damper actuator is seized, the outdoor air sensor is bad, or the controller logic is wrong, the economizer either stays closed (wasting free cooling) or stays open (bringing in hot afternoon air). We test the full economizer cycle: damper stroke, sensor accuracy, and changeover setpoint.
10. Document Everything & Benchmark
We record superheat, subcooling, supply/return temps, amp draws, and static pressure during every visit. This creates a performance baseline. When something starts drifting 6 months later, we catch it before it becomes a failure. This is the difference between reactive and predictive maintenance — and it’s why our commercial clients average 40% fewer emergency calls than industry benchmarks.