Last updated: April 23, 2026
Commercial HVAC service in San Diego County ranges from a $149 service call to a $25,000 rooftop unit replacement on a larger building. Most repair calls land well under $2,500. A full RTU replacement is the big-ticket item, priced by tonnage, and maintenance contracts are priced by square footage rather than a flat rate.
El Cajon hits some of the most extreme summer heat in the urbanized part of the county, 100 to 110 degrees isn't rare, which pushes every system toward larger cooling capacity. Bostonia and the El Cajon Boulevard corridor carry substantial rental-property stock, driving faster-turnaround work, while Fletcher Hills' upper-income homes run larger, higher-tier replacements. Permits route through the City of El Cajon, generally $250 to $450.
East County commercial HVAC carries the highest summer cooling loads in the county, and equipment sized for that load costs more on a full rooftop replacement. Maintenance contracts here focus on predictable monthly cost specifically to avoid an emergency repair during a heat event.
| Item | Typical cost | Notes |
|---|---|---|
| Commercial service visit | From $149 | Diagnostic and minor repair on rooftop or packaged units |
| Rooftop unit (RTU) repair | $400 - $2,500 | Most common repair range, covers motors, boards, and refrigerant work |
| RTU replacement, 3 to 5 ton | $8,000 - $18,000 | Typical for a small retail space or office suite |
| RTU replacement, 7.5 to 10 ton | $15,000 - $25,000 | Typical for a larger retail, restaurant, or warehouse space |
| Preventive maintenance contract | Priced by square footage | Quoted per building, not a flat per-unit rate |
| After-hours or weekend service call | Standard rate | Scheduled around your business hours, no separate overtime surcharge |
Ranges reflect El Cajon and East County San Diego. Your exact figure depends on the factors below. We quote flat-rate before starting.
A preventive maintenance contract catches most rooftop unit failures before they turn into an emergency call during business hours, and it's priced by square footage so a small suite doesn't pay the same rate as a large warehouse. SDG&E offers commercial rebate programs for high-efficiency RTU replacements, and those figures depend on tonnage and efficiency tier, so we confirm the real number for your building rather than quoting one up front.
For a typical 1,400 to 2,200 square foot El Cajon home, expect $10,000 to $19,000 for a properly sized heat pump replacement. The key word is properly sized, El Cajon's 100-plus degree summer days mean an undersized system will run constantly and still lose ground on the hottest afternoons, so we size to actual peak load rather than assume the old tonnage was correct.
East County commercial HVAC carries the highest summer cooling loads in the county, and equipment sized for that load costs more on a full rooftop replacement. Maintenance contracts here focus on predictable monthly cost specifically to avoid an emergency repair during a heat event.
A service call starts at $149. Most repairs run $400 to $2,500. A full rooftop unit replacement runs $8,000 to $25,000 depending on tonnage, with larger buildings needing multiple units.
Yes, for most property owners and businesses. A maintenance contract is priced by square footage and catches problems during a scheduled visit instead of an emergency call that disrupts business hours.
A standard service visit at $149 covers diagnostics and minor adjustments. Most straightforward repairs, like a failed contactor or a refrigerant top-off, stay under $1,000.
A full rooftop unit replacement is the largest expense, running $8,000 to $25,000 depending on tonnage. Buildings with multiple RTUs sometimes replace them in phases to spread out the cost.
Flat-rate pricing, confirmed before any work starts. Same-day scheduling on most calls.