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Earlier editions: 20222019

Chapter 5 — NONRESIDENTIAL AND HOTEL/MOTEL OCCUPANCIES—PERFORMANCE AND PRESCRIPTIVE COMPLIANCE APPROACHES FOR ACHIEVING ENERGY EFFICIENCY

140.5 Prescriptive Requirements for Service Water-Heating Systems — 2025 California Energy Code

California Energy Code (Title 24, Part 6) · 2025 edition · updated 2026-10-19 · California

CBSC: official editions, supplements and errata

Cite as: 2025 California Energy Code (Title 24, Part 6) § 140.5 · Effective January 1, 2026 · Official source: Building Standards Commission

(a) Nonresidential occupancies. Service water-heating systems in nonresidential buildings shall meet the requirements of 1 or 2 below, or meet the performance compliance requirements of Section 140.1:

  1. School buildings less than 25,000 square feet and less than 4 stories in Climate Zones 2 through 15. A heat pump water-heating system that meets the applicable requirements of Sections 110.1, 110.3 and 120.3.

Exception to Section 140.5(a)1: A water-heating system serving an individual bathroom space may be an instantaneous electric water heater.

  1. All other occupancies. A service water-heating system that meets the applicable requirements of Sections 110.1, 110.3, 120.3 and 140.5(c).

(b) Hotel/motel occupancies. A service water-heating system installed in hotel/motel buildings shall meet the requirements of Section 170.2(d).

(c) High-capacity service water-heating systems . Gas service water-heating systems with a total installed gas water-heating input capacity of 1 MMBtu/h or greater shall have gas service water-heating equipment with a minimum thermal efficiency of 90 percent. Multiple units can meet this requirement if the water-heating input provided by equipment with thermal efficiencies above and below 90 percent averages out to an input capacity-weighted average of at least 90 percent.

Exception 1 to Section 140.5(c): If 25 percent of the annual service water-heating requirement is provided by site-solar energy or site-recovered energy.

Exception 2 to Section 140.5(c): Water heaters installed in individual dwelling units.

Exception 3 to Section 140.5(c): Individual gas water heaters with input capacity at or below 100,000 Btu/h shall not be included in the calculations of the total system input or total system efficiency.

Note: Authority: Sections 25213, 25218, 25218.5, 25402 and 25402.1, Public Resources Code. Reference: Sections 25007, 25008, 25218.5, 25310, 25402, 25402.1, 25402.4, 25402.8, and 25943, Public Resources Code.

COMPLIANCE APPROACHES FOR ACHIEVING ENERGY EFFICIENCY

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▸Contents — California Energy Code (Title 24, Part 6)
California Energy Code (Title 24, Part 6)

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