[2] In general, there are two means, or paths for building designers to comply with ASHRAE 90.1: Within the sections of the standard, there are some variations to this.
ASHRAE 90.1 includes prescriptive requirements for the following: In the performance approach, a baseline energy cost budget (ECB) is established, based on the building size and program.
The performance approach is also used to demonstrate design energy efficiency, often expressed as percent better than ASHRAE Standard 90.1.
Percent improvement over ASHRAE 90.1 is the basis for awarding energy points within the LEED rating system.
[4] The California Energy Code (CCR Title 24 Part 6) has a very similar structure and requirements.
ASHRAE 90.1 is also an industry standard referenced by the USGBC in the LEED building certification program.
Outside the US, India's Energy Conservation Building Code, has a similar form and scope to ASHRAE 90.1.
ASHRAE enlisted representatives from the American Institute of Architects (AIA), Illuminating Engineering Society (IES), Mechanical Contractors Association of America (MCAA), Air Conditioning and Refrigeration Institute (ARI), and the Electrical Energy Association (EEA).
Comments were received, revisions were made, and the initial version was issued as ASHRAE Standard 90-1975 on January 14, 1975.
There are also mandatory provisions that building envelopes have to abide by which are insulation, fenestration and doors, and air leakage.
Other revisions affect the maximum fan power limits, pump head calculation, chilled water pipe sizing, radiant panel insulation, single-zone VAV, and supply air temperature reset.
[6][7] In the 2013 edition several updates were made to the building envelope, lighting and mechanical sections of the standard.
DOE issued a positive determination stating that Standard 90.1-2013 would achieve greater energy efficiency in buildings subject to that code.
In the mechanical section, minimum efficiency requirements for many types of HVAC equipment are revised.
Significant changes include a new compliance path known as Performance Rating method included in Appendix G[11] of the standards document, addition of two new weather zones, a new document format and new technical requirements for building envelope, lighting and mechanical systems.
Under the mechanical section modifications include updates to the chilled water plant metering, DOAS, elevator efficiency, economizer fault detection and diagnostics.
The BPF is based on climate zone and building type allowing for greater flexibility in compliance modeling.
Significant changes include: new commissioning requirements per ASHRAE/IES Standard 202;[17] and updates to building Envelope, Lighting, Mechanical, Energy Cost Budget, Performance Rating Method sections.
Under Section 11, Energy Cost Budget (ECB) Method baseline requirement for on-site electricity generation systems are added.
Updates to the Performance Rating Method (Appendix G) section of the standards include clarifications for fan and coil sizing, explicit heating and cooling COP without fan for baseline packaged cooling equipment, new rules for modeling automatic receptacle controls and baseline envelope infiltration and updated building performance factors.
In addition under both compliance paths updated language for treatment of renewables and lighting modeling are included.