San Francisco homeowners planning a major gut renovation will soon have to do something else while they're at it: rip out the gas. A sweeping new electrification rule takes effect July 1.

The ordinance extends San Francisco's existing ban on natural gas in new construction to cover major renovation projects — defined narrowly but with real teeth. Homeowners who trigger it must switch every gas-burning system in the home to electric: space heating and cooling, water heating, cooking, clothes drying. City officials pitch it as a cost-saver. But independent research and contractors working in the city's older neighborhoods point to a friction point the city's estimates don't fully account for: a large share of San Francisco's aging housing stock runs on 100-amp electrical panels that can't support all-electric systems without expensive upgrades — upgrades that aren't covered by the rule's exemptions, and that can run thousands of dollars before a single wall gets touched.

The new rule, reported by the San Francisco Chronicle, doesn't catch every renovation. To trigger it, a project must meet two conditions simultaneously: it must replace core mechanical systems — water heaters, furnaces — and it must involve structural work meeting at least one of three thresholds: substantially moving or modifying walls and ceilings on two-thirds or more of a building's floors; modifying structural elements supporting 30 percent or more of the floor or roof area; or adding new construction valued at 50 percent or more of the building's existing market value.

That's a high bar. The San Francisco Department of the Environment estimates the ordinance will affect roughly 261 single-family homes and 293 multifamily units per year — about 0.2 percent of the city's single-family square footage annually. The city is not trying to catch every kitchen remodel. It is targeting the true gut jobs, the projects where homeowners are already tearing into walls and swapping out mechanicals.

For those projects, city Climate Program Manager Cyndy Comerford says going all-electric often doesn't cost more — and can cost less. A city analysis estimates single-family homes could save around $2 per square foot on major renovations by eliminating gas piping and infrastructure. Small hotels could save $14.56 per square foot. Comerford told the Chronicle that electricity prices have recently been trending down, while natural gas rates are expected to rise faster than electricity between 2025 and 2040.

"Folks see electricity as being a lot more expensive than natural gas," Comerford told the Chronicle. "We have seen some historical increases in electricity, but of late, we've actually seen a decrease in electricity prices."

The savings math depends, however, on a home that can handle an all-electric load without needing its electrical service upgraded. That's where the city's rosy projections run into a harder reality.

Zach Heir, president of Heirloom Builders, a San Francisco general contracting company, told the Chronicle that it's typical for his crews to see single-family homeowners who need to upgrade from 100-amp panels — standard in much of the city's older housing stock — to 200-amp service before all-electric systems can be installed. A 100-amp panel was adequate for a mid-century gas home. It is not adequate for a home running electric heat, an electric water heater, an electric stove, an electric dryer, and potentially an EV charger simultaneously.

Comerford argues that panel upgrades are not always necessary, pointing to load management strategies as a lower-cost alternative. But a 2026 policy brief from the UCLA California Center for Sustainable Communities found that while load management can address panel-capacity issues, most contractors are unfamiliar with those alternatives and often default to upsizing panels — meaning some property owners get steered toward costlier upgrades even when cheaper options exist.

The UCLA researchers also flagged a structural equity concern: electrifying existing properties is "difficult for many existing properties to electrify, especially for lower- and moderate-income households," precisely because those households are more likely to own older homes with undersized electrical infrastructure and less financial cushion to absorb unexpected upgrade costs.

The ordinance does include exemptions. Restaurants and food-service buildings can keep gas for cooking equipment, where the city estimates all-electric renovation costs could reach $39.50 per square foot — a number that made the commercial carveout politically necessary. Projects can also seek an exemption if all-electric design would require utility infrastructure upgrades causing a "substantially greater delay" than a mixed-fuel project. Critically, though, higher cost alone is not grounds for exemption.

The rule's rollout comes as San Francisco has been layering electrification mandates across its housing stock in recent years. The city banned gas in new construction earlier this decade. A separate rule banning gas water heaters in existing homes — for like-for-like replacements — takes effect in 2027. And PG&E's processing times for panel and service upgrades have stretched to as long as two years, a backlog the city does not control.

For the homeowner doing a full gut renovation and already writing six-figure checks, an electrical service upgrade may land as one more line item in a project that already has plenty. For a moderate-income homeowner on a tighter budget, it could be the factor that determines whether a major renovation pencils out at all.

The city's own scale estimates suggest that group is small. But in a city where 0.2 percent of single-family homes still represents thousands of units over a decade, the cumulative reach of the rule may be larger than its annual snapshot implies.