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.
Guatay sits at 3,400 feet along the SR-79 corridor with mountain climate, real winter freeze, and hot dry summers. Rural large-lot residential is the norm, and propane-to-heat-pump conversion is the standard upgrade for the area's older homes. Permits route through the County of San Diego, and severe SDG&E power shutoff exposure is worth factoring into any replacement decision given how isolated Guatay gets during storm events.
Mountain commercial HVAC in Julian, Alpine, and Ramona is lower volume but higher cost per job once drive time and, in some cases, propane-fed rooftop units are factored in. Full replacements here run the highest ceiling in the county range.
| 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 Guatay and Backcountry 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 rural Guatay home, budget $9,000 to $18,000 for a cold-climate-rated heat pump conversion, including removing or capping the old propane line where applicable. Homes on larger parcels near the Cuyamaca Rancho perimeter sometimes need longer refrigerant line runs, which adds modestly to labor cost but not to the equipment itself.
Mountain commercial HVAC in Julian, Alpine, and Ramona is lower volume but higher cost per job once drive time and, in some cases, propane-fed rooftop units are factored in. Full replacements here run the highest ceiling in the county range.
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.