Last year, we saw the efforts of many in the Phius community pay off with a number of policy advancements throughout the country.

In Part I of our blog series, we covered the strides that were made in the Low-Income Housing Tax Credit (Qualified Allocation Plans) and Incentives. For Part II, we will be looking at energy code advancements.

There’s plenty to get to, so enjoy our rundown below, which is organized by municipality.


On Christmas Eve 2022, the Massachusetts Department of Energy Resource (DOER) adopted a new version of the Massachusetts Stretch Code. Since 2010, towns and cities in Massachusetts have enforced one of two energy codes: the base code – typically the latest version of the International Energy Conservation Code (IECC) – or the stretch code. 

The stretch code is typically a certain percentage more efficient than the base code. To gain the ability to enforce the stretch code, a jurisdiction had to adopt it. However, once a jurisdiction adopted the stretch code, they would automatically adopt each updated version of the stretch code without additional votes. This year, the DOER added a new stretch code, the Specialize Opt-in stretch code. A municipality that wants to enforce this new stretch code will need to adopt it (much like the old stretch code). This new Opt-In Code represents an important additional improvement in efficiency from both the IECC and the current stretch energy code. 

The Opt-in code has separate requirements for single-family, residential dwellings over 12,000 square feet and non-residential buildings. For both single-family and non-residential buildings, the Opt-in code provides an alternative compliance for Phius (just as with the stretch code). The major difference resides in residential buildings over 12,000 square feet. These dwellings are now required to meet Phius or other passive house standards.

As there are a number of municipalities planning on adopting the Opt-In stretch code, (the towns of Brookline, Cambridge, Somerville, and Watertown have already adopted the Opt-in code and there are about 20 other towns and cities considering it) Phius can expect a significant increase in Massachusetts projects starting later in 2023.

New York

New York State Energy Research and Development Authority (NYSERDA) is currently reviewing the proposed update to the stretch code (NYStretch 2023), which includes a novel way to incorporate Phius. While New York City does enforce the current stretch code (NYStretch 2020), the city council removed the Phius alternative compliance path before it adopted NYStretch 2020. 

With the new approach to incorporating Phius, it is possible New York City will include Phius when it adopts the updated stretch code. A more detailed explanation of how the new proposed stretch code incorporates Phius will come in a later blog post if the new stretch code is approved by NYSERDA. 


Illinois Governor J.B. Pritzker recently declined to adopt the proposed update to the energy code in Illinois. The Governor has ordered the Capital Development Board (CDB) to reverse proposed amendments to the state energy code that would have made it less efficient than the 2021 International Energy Conservation Code. It is expected that the new version of the base energy code will be approved soon (without any weakening amendments and with a Phius alternative compliance path). 

Concurrently, the Capital Development Board is developing a stretch energy code for the state that will also include an alternative compliance path for Phius (for both the residential and commercial energy codes). The stretch code will be available for local municipalities to adopt (and by adopting the stretch code supersede the base state code). 

The stretch code is scheduled to be completed by the end of 2023. To get a sense of efficiency improvement, the commercial stretch code will be about 4.5% more efficient than the 2021 IECC. Legislation will require the CDB to update the stretch code every three years and includes more stringent energy saving targets with each update. 


The City of Chicago has adopted the Chicago Transformation Code based on the 2021 IECC. The code also includes an alternative compliance path for Phius (the intent here is to provide a path that will lessen the enforcement responsibilities for city plan reviewers and inspectors). The new code also includes electrification-ready and solar-ready provisions along with a requirement that aims to limit thermal bridging in balconies. 


The Vermont Department of Public Service (DPS) is currently working on developing a stretch code. Phius submitted comments for an alternative compliance path, but the DPS has not made a final decision.