Quick answer
In Fallbrook, the right choice depends mostly on what you heat with now and what you pay for electricity. Homes with electric baseboard or wall heat usually save the most by switching to a heat pump. Natural gas homes often pay about the same either way, so a gas furnace still makes sense if your AC is fine. If you also need new air conditioning, a heat pump does both jobs in one system, and Fallbrook needs cooling about as much as heating.
How a furnace and a heat pump differ
A gas furnace burns natural gas or propane to make heat. A blower then pushes warm air through your ducts. A furnace only heats, so most homes pair it with a separate air conditioner.
A heat pump doesn't burn anything. It uses electricity to move heat. In winter it pulls heat from the outside air and brings it inside. In summer it runs in reverse and works as an air conditioner. One system handles both seasons.
| Feature | Gas furnace | Heat pump |
|---|---|---|
| Fuel | Natural gas or propane | Electricity |
| Heats the home | Yes | Yes |
| Cools the home | No (needs a separate AC) | Yes |
| Burns fuel inside the home | Yes (needs venting and a CO alarm) | No |
| Efficiency rating | AFUE, shown as a percent (80% to 98%) | HSPF2 for heating, SEER2 for cooling |
| Federal minimum for new units | 95% AFUE for most new gas furnaces made after December 18, 2028 | HSPF2 7.5 for split-system heat pumps |
Sources: U.S. Department of Energy standards (10 CFR 430.32 and the 2023 furnace rule).
What the ratings mean: AFUE is the share of fuel that turns into heat. An 80% furnace wastes 20 cents of every heating dollar up the vent. HSPF2 measures how much heat a heat pump delivers for the power it uses. A rating of 7.5 means about 2.2 units of heat for every unit of electricity, which is why heat pumps beat plain electric heaters by a wide margin.
Fallbrook's climate favors heat pumps
Heat pumps lose some power in very cold weather. Fallbrook rarely gets cold enough for that to matter. NOAA's 30-year climate normals for the Fallbrook weather station show freezing nights almost never happen.
| Fallbrook climate measure | 30-year average |
|---|---|
| Heating degree days per year | 1,368 |
| Cooling degree days per year | 1,412 |
| Average winter low (December to February) | 46.6°F |
| Nights below 40°F | 13.4 per year |
| Nights below 32°F | 0.2 per year |
| Average August high | 89.3°F |
Source: NOAA NCEI U.S. Climate Normals 1991 to 2020, station Fallbrook 5 NE (USW00053151). Degree days use a 65°F base.
Two things stand out. First, winters are mild enough for any standard heat pump. Second, Fallbrook has slightly more cooling demand than heating demand. A home here needs air conditioning about as much as it needs heat, so a system that does both carries real weight. Fallbrook ZIP codes 92028 and 92088 fall in California building climate zone 10, an inland zone with hotter summers than the coast (most of coastal San Diego is zone 7).
Yearly heating cost compared
The table below estimates what it costs to heat the same Fallbrook home with each system. It uses Fallbrook's heating degree days and current local or state energy prices.
| Heating system | Energy price used | Estimated yearly heating cost |
|---|---|---|
| Natural gas furnace, 80% AFUE | $2.648 per therm | $435 |
| Natural gas furnace, 96% AFUE | $2.648 per therm | $362 |
| Propane furnace, 80% AFUE | $2.73 per gallon | $490 |
| Propane furnace, 96% AFUE | $2.73 per gallon | $408 |
| Heat pump, HSPF2 7.5 (federal minimum) | 29.75¢ per kWh | $521 |
| Heat pump, HSPF2 9.0 (high efficiency) | 29.75¢ per kWh | $434 |
| Electric baseboard or wall heater | 29.75¢ per kWh | $1,145 |
Model estimate, not a quote. Assumes a home heat loss of 400 BTU per hour per °F and NOAA's 1,368 Fallbrook heating degree days (about 13.1 million BTU of heat a year). Prices: SDG&E August 2026 average residential gas rate; EIA U.S. average residential propane, October 2026; EIA California average residential electricity, August 2026. Excludes fan power and duct losses.
The biggest gap isn't gas versus heat pump. It's plain electric heat versus a heat pump. A heat pump uses roughly 60% less electricity than baseboard or wall heaters to make the same heat. Between gas and a heat pump, the yearly difference is small at the state average power price, and your own electric rate decides the winner.
Your break-even electric rate
Your electric bill shows what you pay per kilowatt-hour (kWh). Compare it with the numbers below. If your rate is below the break-even point, a heat pump costs less to run than the furnace listed. If it's above, the furnace costs less to run.
| Heat pump compared with | Standard heat pump (HSPF2 7.5) | High-efficiency heat pump (HSPF2 9.0) |
|---|---|---|
| Natural gas furnace, 80% AFUE | 24.8¢ per kWh | 29.8¢ per kWh |
| Propane furnace, 80% AFUE | 28.0¢ per kWh | 33.6¢ per kWh |
Calculated from the same model and fuel prices as the cost table above. Break-even rates move up when gas or propane prices rise.
For context, the average residential electricity price in California was 29.75¢ per kWh in August 2026, according to the U.S. Energy Information Administration. That's about 64% above the national average of 18.16¢. Rates vary by utility, plan, and time of day, so use the rate on your own bill. If you have rooftop solar, your effective rate may be much lower, which tilts the math toward a heat pump.
Best choice by what you heat with now
Census data shows how Fallbrook homes are heated today. Your current fuel is the biggest clue to which system makes sense next.
| Current heat | Share of Fallbrook homes | Usual best fit |
|---|---|---|
| Natural gas furnace | 47.8% | Either. A gas furnace if your AC is fine; a heat pump if you need new AC too or have solar. |
| Propane furnace | 14.2% | Often a heat pump, especially if you also need AC or want to drop the tank. |
| Electricity (baseboard, wall heater, or older heat pump) | 30.9% | Usually a heat pump. Switching from plain electric heat saves the most. |
| Wood, solar, or other | 7.1% | Depends on the home |
Source: U.S. Census Bureau, American Community Survey 2024 5-year estimates, table B25040, Fallbrook CDP.
About three in ten Fallbrook homes heat with electricity, a large group for whom a heat pump can cut heating costs by more than half. Fallbrook also relies on propane far more than San Diego County as a whole (14.2% versus 3.3%), mostly in rural areas without a gas line.
What Fallbrook homeowners are installing
San Diego County's public permit records show the kind of heating and cooling work being done in Fallbrook. From 2013 to 2023, the County issued 824 online HVAC replacement permits there.
| Permit type (Fallbrook, 2013 to 2023) | Permits |
|---|---|
| HVAC change-out (furnace, split, or package system) | 716 |
| Electric heat pump or AC replacement | 108 |
Source: County of San Diego open data, "Building Permits" dataset, scope codes 8023 and 8025, city = Fallbrook. The heat pump code also covers AC-only swaps, and the dataset ends in December 2023.
Most Fallbrook replacements in the records are full HVAC change-outs, which often keep a furnace paired with AC. Many heat pump installs fall inside those change-out permits too, so the County data can't show the exact split between gas and electric heat.
2026 rules that affect the choice
- Federal furnace standard: most new non-weatherized gas furnaces made on or after December 18, 2028 must reach 95% AFUE. The rule is still in effect while a court challenge continues, and the Department of Energy is weighing a delay to 2030. Older homes may need new venting for these condensing furnaces.
- Federal heat pump standard: new split-system heat pumps must meet at least SEER2 14.3 and HSPF2 7.5.
- California's 2025 Energy Code: it applies to permits filed on or after January 1, 2026, and expands heat pump use in newly built homes. Either system needs a County permit when it replaces an existing one.
- Federal tax credit: the Section 25C credit for heat pumps and furnaces ended for equipment placed in service after December 31, 2025. State and utility rebates change often, so check current offers before you buy.
- Electrical work: switching from gas to a heat pump can need a new circuit or a panel upgrade. That work needs its own County permit.
Questions to ask before you decide
- What fuel heats your home now: gas, propane, or electricity?
- Does your air conditioner also need replacing soon?
- What's your electric rate per kWh, and do you have solar?
- Does your electrical panel have room for a heat pump circuit?
- Are your ducts in good shape, or do they need sealing?
- How long do you plan to stay in the home?
Still not sure your current system needs replacing? See whether to repair or replace your furnace, read how furnace permits work in Fallbrook, or learn how a new furnace install in Fallbrook is planned.
Weighing a furnace against a heat pump?
Call Now +1 760 907 0482FAQ
Does a heat pump work in Fallbrook winters?
Yes. Fallbrook averages a winter low of 46.6°F and only about 0.2 freezing nights a year, based on NOAA's 30-year climate normals. Standard heat pumps handle these temperatures without needing backup heat most of the time.
Is a heat pump cheaper to run than a gas furnace in Fallbrook?
It depends on your electric rate. A standard heat pump costs less to run than an 80% gas furnace when electricity is below about 24.8¢ per kWh, or about 29.8¢ for a high-efficiency heat pump. At California's August 2026 average of 29.75¢, the two cost about the same per year.
Should I replace my electric baseboard heat with a heat pump?
Usually yes. A heat pump makes the same heat with roughly 60% less electricity. In the model for a typical Fallbrook home, yearly heating drops from about $1,145 with baseboard heat to about $434 to $521 with a heat pump.
Is a heat pump better for propane homes?
Often. An 80% propane furnace costs more to run than a standard heat pump whenever electricity is below about 28¢ per kWh. About 14.2% of Fallbrook homes heat with propane, compared with 3.3% across San Diego County.
Does a heat pump replace my air conditioner?
Yes. A heat pump heats in winter and cools in summer. That matters in Fallbrook, which averages 1,412 cooling degree days a year, slightly more than its 1,368 heating degree days.
Do I need a permit for a heat pump in Fallbrook?
Yes. San Diego County requires a permit to replace heating and cooling equipment in unincorporated areas like Fallbrook. The County offers an online permit for electric heat pump or AC replacement, and added electrical work needs its own permit.
Sources and methodology
Cost figures come from a simple model that applies the same yearly heat need to each system. They're estimates for comparing options, not measurements of any one home. Actual costs depend on home size, insulation, ducts, thermostat settings, and your energy plan.
- NOAA National Centers for Environmental Information, U.S. Climate Normals 1991 to 2020, station Fallbrook 5 NE (USW00053151).
- U.S. Census Bureau, American Community Survey 2024 5-year estimates, table B25040 (house heating fuel), Fallbrook CDP and San Diego County, via Census Reporter.
- U.S. Energy Information Administration, Electric Power Monthly, Table 5.6.A (August 2026 average residential price by state).
- U.S. Energy Information Administration, Weekly Residential Propane Prices (U.S. average, October 26, 2026).
- San Diego Gas & Electric, Natural Gas Rate Change Alert, August 2026 (bundled residential average of $2.648 per therm).
- U.S. Department of Energy, 10 CFR 430.32 (heat pump SEER2 and HSPF2 minimums) and the 2023 consumer furnace standard.
- California Energy Commission, Building Climate Zones by ZIP Code, and 2025 Building Energy Efficiency Standards.
- County of San Diego, Open Data Portal, "Building Permits" dataset (dyzh-7eat).
- Internal Revenue Service, Energy Efficient Home Improvement Credit.