Heat pump vs. AC + gas furnace in San Diego — which actually saves money?
Most San Diego homes used to default to a split AC + gas furnace combo. In 2026 — with SDG&E rebates + federal 25C credits stacked — heat pumps beat the combo on install cost, operating cost, and payback for the majority of county homes. But not all. Here's the honest comparison.
The short version
For 80% of SD County homes, a heat pump is now the better install. The exceptions are backcountry homes above 3,000 ft elevation (where heat loads compete with cooling loads) and homes with existing gas service they want to keep using. Coastal + inland + East County + South County are almost always better on heat pump in 2026.
Side-by-side
| Dimension | Heat pump (all-electric) | AC + gas furnace |
|---|---|---|
| Install cost (typical 3-ton) | $12,000–$18,000 before rebates | $10,000–$15,000 |
| 2026 rebates available | Up to $3,100 SDG&E + $2,000 federal 25C tax credit = $5,100 possible | None for AC + gas furnace replacement |
| Net install cost after rebates | $7,000–$13,000 | $10,000–$15,000 |
| Annual operating cost (coastal SD) | $450–$750 | $700–$1,200 (AC) + $200–$400 (gas) |
| Efficiency (rated) | HSPF2 7.5–9.0, SEER2 15–20 | AFUE 80–95% furnace + SEER2 15–17 AC |
| Heating capacity in cold weather | Designed for mild climates; derated below 35°F | Full capacity at any temperature |
| Gas service required | No — all-electric | Yes — SDG&E gas service + meter |
| Maintenance | Single outdoor unit + air handler | Two systems to service + annual gas furnace inspection |
| Lifespan | 15–20 years | 15 years AC + 20–25 years furnace |
Heat pump (all-electric) — pros
- Lower net install cost after rebates stack
- Lower operating cost in SD's mild climate
- No gas service needed — reduce SDG&E bill to electric only
- Eligible for NEM 3.0 solar offsets
- Single system = single maintenance contract
- Lower carbon footprint (all-electric)
Heat pump (all-electric) — cons
- Derated below 35°F — backcountry above 3,000 ft sees this in winter
- Requires adequate panel capacity (check with panel-load calc)
- Refrigerant-cycle repairs cost more than gas-furnace repairs
AC + gas furnace — pros
- Full heating capacity at any outdoor temperature
- Gas heat feels warmer (hotter air delivery temp)
- Separate systems = backup if one fails
- Gas furnace lasts longer than heat pump (20–25 years)
AC + gas furnace — cons
- No rebate stacking in 2026
- Two systems, two maintenance cycles
- Higher combined operating cost in SD's mild climate
- Gas service fixed monthly charge on SDG&E bill
- Combustion safety (CO risk, venting requirements)
When Heat pump (all-electric) is the right call
- Coastal, inland, East County, South County SD homes (climate is mild enough)
- Homeowners who want to go all-electric + add solar
- Homes with 200A+ panels (or where panel upgrade is already planned)
- Homeowners who qualify for enhanced SDG&E income-tier rebates
When AC + gas furnace is the right call
- Backcountry homes above 3,000 ft (Julian, Palomar, Pine Valley)
- Homeowners keeping gas service for cooking + water heater
- Homes with 100A panels where upgrade isn't in the budget
- Homeowners replacing a failed furnace mid-winter (faster install with existing gas service)
FAQ
What about backup heat strips?
Most heat pump installs in SD include electric backup strips in the air handler — they engage below ~35°F outdoor temp when the heat pump derates. The strips are less efficient (~COP 1.0 vs 2.5-3.5 for the pump) but they cover the ~5-10 days per year where metro SD actually needs them.
Will a heat pump heat my house in a cold snap?
Yes, with backup strips engaged. SD metro rarely sees overnight lows below 40°F, which is well within the efficient operating range of modern cold-climate heat pumps. Backcountry homes above 3,000 ft see 20-35°F overnights a few weeks per year — that's where the efficiency math shifts.
Do heat pumps actually reduce my total SDG&E bill?
Yes for all-electric homes. When you remove gas service, the fixed gas-meter monthly charge (~$12-15/month) goes away, and your all-electric usage stays within SDG&E's tiered residential rate plan or EV-TOU-5 if you also have an EV. Net savings typically $250-500/year vs AC + gas furnace.
Can I keep gas for the kitchen but go heat pump for HVAC?
Absolutely — that's a common install pattern. Keep the gas range + water heater, swap HVAC to heat pump. Qualifies for all the same HVAC rebates. The all-electric path only matters if you're also willing to swap range + water heater (separate decisions).
What size heat pump do I need?
Same size as the AC you'd install — our Manual J load calc sizes for cooling first in SD, and heating loads are almost always smaller. Use our BTU calculator at /resources/hvac-calculator/ for a starting estimate; we run a full Manual J before quoting.
Not sure which setup fits your home?
Five-minute phone conversation. We'll tell you honestly whether heat pump or AC + furnace is the better install for your specific SD home, panel, and budget.
Call (858) 808-6055