Replacing a commercial rooftop unit
A new rooftop unit is an alteration. The code treats it like one.
Replace the rooftop unit on a shop, an office or a restaurant and California's nonresidential Energy Code comes with it. In the Bay Area a gas packaged unit can also count as a furnace under the Air District's rule.
The rules
What a rooftop replacement brings with it
The state's rules first, then the Air District's. Your city's permit comes after.
On file, last checked 2026-10-22
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California
Replacement, not maintenance
Changing filters or belts doesn't trigger the prescriptive requirements. Replacing equipment, such as installing a new air handler, does.
Source: California Energy Commission, 2025 Nonresidential and Multifamily Compliance Manual (CEC-400-2025-008). Rules and programs change: last checked 2026-10-22.
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California
Small single zone units
A new or replacement single zone rooftop air conditioner that cools less than 65,000 Btu/hr must follow the rules in Table 141.0-E-1 or meet the performance standards in Section 141.0(b)3.
Source: California Energy Commission, 2025 Nonresidential and Multifamily Compliance Manual (CEC-400-2025-008). Rules and programs change: last checked 2026-10-22.
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California
Acceptance tests
Acceptance requirements apply to equipment installed in an alteration the same way they do in a new building, and the mechanical tests are completed by a technician credentialed through a CEC-approved provider.
Source: California Energy Commission, 2025 Nonresidential and Multifamily Compliance Manual (CEC-400-2025-008). Rules and programs change: last checked 2026-10-22.
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California
A smart thermostat
When a single zone unit is altered and its thermostat doesn't comply with Section 110.12(a), the thermostat is replaced with one that does: an occupant controlled smart thermostat, able to respond to demand response signals when the grid is strained.
Source: California Energy Commission, 2025 Nonresidential and Multifamily Compliance Manual (CEC-400-2025-008). Rules and programs change: last checked 2026-10-22.
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California
Scheduling and setback controls
New systems in alterations need scheduling and setback controls.
Source: California Energy Commission, 2025 Nonresidential and Multifamily Compliance Manual (CEC-400-2025-008). Rules and programs change: last checked 2026-10-22.
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California
Fault detection on bigger air handlers
A newly added air handler with an economizer and 54,000 Btu/hr or more of mechanical cooling needs a fault detection and diagnostic system.
Source: California Energy Commission, 2025 Nonresidential and Multifamily Compliance Manual (CEC-400-2025-008). Rules and programs change: last checked 2026-10-22.
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California
Duct sealing on small systems
New or replacement ducts that meet the code's small single zone criteria are sealed to a leakage rate not to exceed 6 percent of the air handler's nominal airflow, confirmed by ECC acceptance testing.
Source: California Energy Commission, 2025 Nonresidential and Multifamily Compliance Manual (CEC-400-2025-008). Rules and programs change: last checked 2026-10-22.
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Bay Area
Gas heat can count as a furnace
A packaged unit with natural gas heat, a heat input under 175,000 BTU/hr and electric cooling under 65,000 BTU/hr falls under the Air District's zero-NOx furnace rule.
Source: Bay Area Air District, Regulation 9 Rule 4 (adopted March 15, 2023). Rules and programs change: last checked 2026-10-22.
Hayward
Hayward requires a building permit to remove and replace a commercial HVAC unit, or to install one for the first time.
A replacement on the roof can also call for structural calculations stamped and signed by an engineer, showing the existing roof framing will carry the new unit and the curb attachment will resist lateral loads.
Source: City of Hayward, Commercial HVAC System Replacements. Rules and programs change: last checked 2026-10-17.
Burlingame
Burlingame files furnace, AC, heat pump and rooftop unit replacements on a commercial building under its Commercial Mechanical permit type.
Source: City of Burlingame, Online Permitting Portal and Submittal Instructions. Rules and programs change: last checked 2026-10-17.
Tell us the unit and the building
Its size, its fuel and what the building is used for decide which of these rules apply. We'll go through them before we quote.
Tell us what it's doing. We'll take it from there.
Call and describe the problem: the noise, the smell, the room that never warms up. Or book a visit online.
