The most common questions about energy codes, standards, and compliance

At Clearbrook Energy Solutions, we’re here to make navigating energy codes and standards easier, faster, and more practical for design teams and building owners.

To kick things off, we've answered some of the most common questions about energy codes, standards, and compliance strategies.

Why is Energy Code Compliance required?

In the U.S., most states require the adoption and enforcement of building codes, which are necessary for obtaining a building permit. Energy codes are a specific type of building code, alongside fire, electrical, mechanical, fuel gas, and plumbing codes. Owners, developers, designers, and contractors are responsible for ensuring compliance with applicable energy code provisions, and they assume liability for meeting these requirements.

What are Energy Codes based on?

Most states adopt the IECC, developed by the International Code Council (ICC). For commercial projects, the IECC allows ASHRAE Standard 90.1, developed by ASHRAE, as an alternative compliance path. California uses its own energy code, Title 24. Some states and cities, such as Massachusetts, Washington, Denver, and New York City, adopt customized amendments or local stretch codes that are often more stringent than the national models.

What do the Energy Codes cover?

Both IECC and ASHRAE 90.1 cover envelopes, mechanical, electrical, plumbing, and commissioning. 90.1 2022 started covering renewables. Each section has Mandatory and Prescriptive provisions. Mandatory provisions are applicable regardless of the compliance path. Prescriptive provisions are mostly not applicable or can be traded-off with the performance path, also known as energy models.

How often do Energy Codes/Standards get updated?

Every 3 years, there is a two-year gap between IECC and ASHRAE 90.1. The table below shows their equivalencies.

Are IECC and ASHRAE 90.1 the same?

They are very similar, but there are some major differences in their mandatory and prescriptive provisions. IECC is a code while ASHRAE 90.1 is a standard.

Generally, IECC was slightly less stringent than 90.1 until the IECC 2021 version. IECC 2021 became more stringent than ASHRAE 90.1 2019.

What compliance options are in IECC and ASHRAE 90.1?

1) Mandatory + Prescriptive: follow whatever applicable provisions require. Envelope insulations can follow either the R-value table or U-Value table. Or

2) Mandatory + envelope component performance and MEP Prescriptive. This option allows trade off insulations between different envelope components, i.e. higher roof insulation and less wall insulation. In 90.1 2022, mechanical allows trade-offs within HVAC systems Or

3) Mandatory + Whole Building Performance. This option uses an energy model to evaluate the integrated performance of envelope and MEP systems. Prescriptive provisions are not applicable.

COMcheck can be used for option 1) or 2). An energy model report and all relevant supporting documents should be submitted for option 3).

Can I use both IECC and ASHRAE 90.1 on my project?

No, the whole project team, including architects, MEP engineers, and the energy modeler, have to use the same code/standard throughout the entire project. No cherry-picking. No mix and match. For example, if the architect uses IECC 2018, MEP engineers should NOT use ASHRAE 90.1 2016, and the energy modeler should NOT run an ASHRAE 90.1 energy model for compliance. The reason is that IECC 2018 and ASHRAE 90.1 2016 have some very distinctive mandatory and prescriptive provisions. If the design team picked IECC 2018, meaning they are subject to its mandatory requirements, not ASHRAE 90.1. So the energy modeler should run the model based on IECC 2018 for compliance.