Heat pump or air conditioner in Southern California, and what the gas furnace rules really say

What is the difference between a heat pump and an AC?

A central air conditioner cools, so the house still needs a furnace for heat. A heat pump moves heat out of the house in summer and into it in winter. The Department of Energy says that in moderate climates, heat pumps can be an energy-efficient alternative to furnaces and air conditioners.

CARB's clean heater FAQ adds two points. In a home that already has central air, a heat pump can often replace both the furnace and the AC in the same space. And electricity costs more per unit than gas, but a heat pump uses so much less energy that running costs can come out lower over time. Prices, permits and the Title 24 testing are in our HVAC replacement cost guide.

Is California banning gas furnaces?

Not yet. CARB is writing a clean space and water heater standard, but its FAQ (last updated July 13, 2026) says the rule is not final and no formal proposal has gone to the CARB Board. The latest concept, from a December 11, 2025 workshop, would limit the share of gas units each manufacturer can sell in California from 2030, with credits for those that sell more zero-emission units:

• Furnaces and other space heaters: up to 40 percent of sales could still burn gas in 2030, falling to 25 percent from 2045.
• Water heaters: 60 percent in 2030, falling to 50 percent from 2045.

Those numbers are a draft and can change. CARB says the rule would not make anyone replace working equipment, and you could keep using and repairing a gas furnace after 2030.

What do the South Coast AQMD rules require?

Every Orange County city is on the district's jurisdiction list, from Brea and La Habra to Laguna Beach and San Clemente. Two of its rules cover home heating:

• Rule 1111 covers gas central furnaces under 175,000 Btu per hour. A new one sold or installed must be certified to 14 nanograms of nitrogen oxides (NOx) per joule of heat. The board's most recent change, on January 9, 2026, only extended to September 30, 2030 the option for mobile home furnace makers to pay a fee instead of meeting that limit.
• Rule 1121 covers gas water heaters under 75,000 Btu per hour, with a limit of 10 nanograms per joule phased in from 2006 to 2008. It was last amended September 3, 2004.

Staff proposed amendments to both rules that would have set zero-NOx limits for new installations, with a sales target option for manufacturers, with later dates for existing buildings than for new ones. On June 6, 2025, the board voted 7 to 5 not to approve them, so the older rule language stays in effect. Both rules apply to the companies that make, sell and install the equipment, not to homeowners.

Which heat pump rebates are open in Orange County?

The air district's GO ZERO program opened its Phase 2 single-family portal on November 6, 2026, for work installed on or after September 4, 2026. Its FAQ lists these Phase 2 rebates, which it says can change:

• Heat pump heating and cooling under 3 tons: $500, or $1,000 in an overburdened community.
• Heat pump heating and cooling, 3 tons or more: $1,000, or $2,000.
• Heat pump water heater: $500, or $1,000.

The heat pump must replace a gas or propane furnace or water heater, be ENERGY STAR certified unless the FAQ says otherwise, and have a finalized permit. A heat pump that replaces only an air conditioner does not qualify. Each home can get one heating and cooling rebate and one water heating rebate.

Two other programs people ask about are not open here. TECH Clean California's single-family page lists no Orange County offer; its newest one, added November 2, 2026, is for San Fernando Valley homes near the Aliso Canyon gas storage site. ENERGY STAR says the federal heat pump tax credit covered products bought and installed from January 1, 2023 to December 31, 2025. Utility rebates are on our Orange County home rebates page.

What should I check before replacing a furnace or AC?

The electrical panel. CARB says many homes with 100 to 200 amp panels can run electric heating, but some need a bigger one; our panel upgrade guide covers that. A gas water heater is the same decision, and our water heater guide covers the straps and permit either way. Every city is on the Orange County hub.

As of November 2026. CARB's standard is a proposal, and rebate amounts and funding change; the agency and program pages have the final word. This is general information, not construction or tax advice.