The Building Emissions Saving Ordinance (BESO) is a point-of-sale requirement in the city of Berkeley. Starting January 1, 2026, it now requires most home sellers to do more than disclose an energy assessment: single-family homes and duplexes must get a Home Energy Score, post it on the MLS listing, and either complete energy upgrades or hand the responsibility to the buyer before the sale closes. If you're buying or selling in Berkeley, here's what actually changed and what you need to do about it.
Why Berkeley Has BESO
In keeping with its long-standing focus on protecting the environment, Berkeley has spent years researching how to cut building-related emissions. That research found that a large share of the city's overall greenhouse gas output comes from buildings, largely from space heating, water heating, and appliances that still run on gas.
The Berkeley City Council responded by creating BESO, now formalized as Berkeley Municipal Code 19.81. Its stated goal is to make building energy use "more transparent to owners and prospective renters or buyers" and to push owners toward real efficiency and electrification upgrades, not just paperwork.
The Big Change for 2026: Resilience Upgrades, Not Just an Assessment
For years, BESO only required an energy assessment at the time of sale. That's no longer true for small residential properties. As of January 1, 2026, anyone selling a single-family home or duplex in Berkeley must complete a two-step process before closing.
Main Takeaway: The old BESO process (hire an assessor, file a report, done) still applies to triplexes, fourplexes, and larger buildings. Single-family homes and duplexes now face a higher bar: an actual energy upgrade, or a funded plan to complete one.
Step One: Get a Home Energy Score
Before listing, the seller must hire a qualified Home Energy Score assessor from the city's registered assessor list, get a separate score for each unit, and post the score in the MLS listing's property notes. The report also has to be included with the disclosure and transfer documents at closing. Scores are valid for five years, and skipping this step brings a $500 non-compliance fee.
Step Two: Upgrade, Qualify for an Exemption, or Defer to the Buyer
Sellers then choose one of three paths:
- Complete upgrades before selling. Install enough improvements to earn at least six credits under the city's Resilience Standard, covering things like a heat pump water heater or heat pump HVAC system (6 credits each), solar PV or a battery storage system (3 credits each), an EV charger or induction range (2 credits each), and smaller measures like attic insulation, duct sealing, or air sealing (1 to 2 credits). Submit documentation through the BESO Portal and pay a $150 filing fee to get a Certificate of Compliance.
- Qualify for a heat pump exemption. If every unit already runs on an electric heat pump for water and space heating, the building may skip the upgrade requirement entirely, though it still needs to be filed on the portal.
- Defer to the buyer. The seller and buyer jointly submit a Upgrade Deposit Form and put $5,000 in escrow with the city ($2,500 from each side). The buyer then has two years to complete the six-credit upgrade, file it with the city, and get the deposit refunded.
Local Tip: If you're selling and don't want to take on a renovation before closing, the deferral option keeps the deal moving. Just budget for your half of the $2,500 deposit and loop in your agent and title company early, since the paperwork has to be coordinated between both sides before close of escrow.
A Few Exemptions Still Apply
All-electric homes with capped gas lines, and buyers enrolled in an income-qualified first-time homebuyer program such as CalPLUS or MyHome, are exempt from the upgrade requirement (with verification). Condominiums and accessory dwelling units aren't covered by these small-residential rules at all.
What If You Own a Triplex, Fourplex, or Larger Building?
Triplexes and fourplexes stay on the older, assessment-only process until January 2028, when they'll transition to the same Resilience Standard as single-family homes and duplexes. Until then, and permanently for multifamily (3+ unit) and commercial buildings under 25,000 square feet, sellers still just need to:
- Check the building's status on the BESO Portal. If it already shows "Compliant," "Exempt," or "Pending - Deferral to Buyer Requested," you're set.
- If not, hire a registered BESO assessor for a full energy assessment, complete a qualifying efficiency or electrification upgrade (such as the Bay Area Multifamily Building Enhancement Program), or apply to defer the assessment to the buyer, who then has six months to complete it.
- File the paperwork and pay the applicable fee: $79 for buildings under 5,000 square feet (including single-family homes and duplexes sold before January 1, 2026), $152 for 5,000 to 24,999 square feet, and $110 for a Deferral to Buyer.
Buildings of 25,000 square feet or more follow a different track entirely: annual energy benchmarking plus a full energy assessment every five years, with a $275 filing fee. Owners can check their building's standing on the city's large building compliance list.
Why Bother Upgrading Instead of Just Deferring?
Even outside of BESO's requirements, improving a home's energy efficiency gives sellers a real edge. Beyond the environmental upside, a thoughtful retrofit can enhance the overall appeal of the property and, over time, pay for itself. If you're weighing your options as part of a broader listing plan, it's worth folding BESO into the conversation you're already having about preparing your home for the market.
Fees at a Glance
Requirement | Fee |
|---|---|
Home Energy Score non-compliance (1-2 units) | $500 |
BESO Certificate of Compliance filing (1-2 units, after upgrades) | $150 |
Resilience Upgrade Deposit (split buyer/seller, refundable) | $5,000 |
Energy assessment, buildings under 5,000 sq ft (incl. 3-4 unit and pre-2026 sales) | $79 |
Energy assessment, 5,000-24,999 sq ft | $152 |
Deferral to Buyer (Form C) | $110 |
Large building (25,000+ sq ft) assessment filing | $275 |
Questions? Contact BESO Directly
For anything specific to your property, hardship deferrals, or exemption applications, reach out to the BESO Helpdesk directly at [email protected] or (510) 981-7465.
Not in Berkeley?
Berkeley is often on the leading edge of environmental policy, and other East Bay cities tend to watch closely before adopting similar rules. Regardless of where you live, it benefits everyone to think about a home's environmental footprint before listing or buying.
Looking for common-sense advice on BESO or energy-efficient retrofits? Red Oak Realty is carbon neutral and green certified, and we're genuine advocates for responsible building practices. Contact us; we're happy to help you work through it.
