Sacramento HVAC contractors raise rates roughly 30% from late June through early September because demand exceeds supply. The same exact tune-up that's $159 in May becomes $220+ during a heat wave.
What a real tune-up includes: refrigerant pressure check, condenser coil cleaning, evaporator coil inspection, blower motor amp draw test, capacitor health check, thermostat calibration, and condensate drain flush.
What a discount $79 'tune-up' usually skips: refrigerant pressure (the #1 indicator of system health) and capacitor measurement (the #1 cause of mid-summer failures).
Verified HVAC pros on HandyMandyMan in Sacramento publish their tune-up checklists upfront. You see what you're getting before you book.