Opt-In Specialized Stretch Energy Code

The Municipal Opt-In Specialized Stretch Energy Code (“Specialized Code”) was developed by the Commonwealth in 2022 as an option for municipalities. Needham voted to adopt the Specialized Code during Special Town Meeting on October 30, 2023. All compliance pathways under the Specialized Code are designed to ensure that new construction is consistent with Massachusetts’ net-zero by 2050 goals, primarily through a combination of energy efficiency, which enables reduced heating loads, and efficient electrification. The effective date of the code in each municipality depends on when the municipality voted to adopt the code. In Needham, the Specialized Code took effect July 1, 2024.

Background

There are three levels of building energy codes in Massachusetts: the Base Code, the Stretch Code, and the Specialized Code.

The Base Code is the International Energy Conservation Code (IECC) with Massachusetts-specific amendments. The base code is part of the building codes governed by the state Board of Building Regulations and Standards (BBRS). In 2023, the base code was updated from the 2018 IECC to the 2021 IECC, and MA amendments added wiring for electric vehicles and maintaining solar ready roof requirements.

In 2009, Massachusetts became the first state to adopt an above-code appendix to the “base” building energy code. The Stretch Code emphasizes energy performance and was designed to result in cost-effective construction that is more energy efficient than that built to the Base Code. The Stretch Code is typically updated every few years, with the most recent update taking effect in 2023. The Stretch Code increases the energy efficiency requirements for all new residential and commercial buildings, as well as for additions and renovations that require building permits. The Stretch Code is now published and maintained by the Massachusetts Department of Energy Resources. Adopting the Stretch Code is a requirement for participation in the Green Communities program. Needham has been a Green Community since 2020. 

The Specialized Code was developed in 2022, following direction from the Commonwealth’s Climate Act of 2021 to develop a municipal opt-in code that advanced net-zero building performance. The Specialized Code builds on the efficiency and clean energy standards in the updated Stretch Code and pushes new construction towards deep energy efficiency, reduced heating loads, consumer protection, and efficient electrification. Use of fossil fuels, such as gas or propane, under the Specialized Code is permitted, but comes with additional requirements for on-site solar generation and pre-wiring for future electrification of any fossil fuel using equipment. The Stretch Code is published and maintained by the Massachusetts Department of Energy Resources.

What does the Specialized Code require?

The Specialized Code builds off the Stretch Code and only adds requirements to new construction.* The Specialized Code is found as an appendix to both the Residential Low-Rise Stretch Energy Code (225 CMR 22.00) and the Commercial Stretch Energy Code (225 CMR 23.00). The Specialized Code can be summarized generally as follows:

1. No additional requirements beyond the Stretch Code for additions, alterations, or renovations.
2. No additional requirements beyond the Stretch Code for all-electric new construction, except for multifamily housing over 12,000 square feet.
3. Any new residential or commercial construction using fossil fuel combustion systems (except multifamily housing over 12,000 square feet) will need to:
   • Provide pre-wiring for future appliances and HVAC electrification. 
   • Install a minimum amount of solar (with some exceptions for shading).
   • Homes over 4,000 square feet must install enough solar or other renewables to offset all the home’s energy use.
4. Any new multifamily housing over 12,000 square feet will need to meet Passive House standards.

*Please note that in accordance with Needham Building Code, any tear downs of 50% or more of the building footprint are considered "new construction."

Frequently Asked Questions

Where can I read more about the updated Stretch Code and Specialized Code?

The Stretch and Specialized codes are new regulations in 225 CMR 22.00 and 225 CMR 23.00. CMR 22.00 covers residential low-rise construction and CMR 23.00 covers commercial and all other construction (including most multi-family).

How is the Specialized Code different from the Stretch Code?

The Specialized Code has accelerated adoption of more efficient Home Energy Rating System (HERS) rating thresholds (HERS 42 and 45) and provides three paths for low rise residential compliance, including a zero-energy pathway (with solar PV). It also requires new homes over 4,000 sq ft to follow the all-electric or zero energy pathway. Solar PV is required for any new construction utilizing fossil fuels for heating. The Specialized Code for multi-family housing 4 stories and above phases in Passive House standards. 

What is a HERS rating?

HERS stands for “Home Energy Rating System” and is a national standard that uses information on the design of the energy systems in a home to calculate, via computer modeling, the average energy needs of that home and give it a rating score. The HERS Index was developed by the non-profit Residential Energy Services Network (RESNET) for the mortgage industry and is utilized by the Federal Internal Revenue Service (IRS) and the LEED for Homes program. On the HERS 2006 index scale smaller numbers are better, with 0 representing a net zero energy home, and 100 representing a home built according to meet the national model energy code in 2006 (the IECC 2004 with 2005 amendments). A HERS rating of 52 means that the home uses about 48% less energy than the same size home built to the 2004/2005 IECC code requirements.

What building types does the Stretch Code and Specialized Code apply to?

The Stretch Code applies to both residential and commercial new construction, as well as certain renovations and additions. The Specialized Code applies only to residential and commercial new construction.

What is Passive House?

Passive House is a performance-based building certification that focuses on the dramatic reduction of energy use for space heating and cooling. It results in significantly lower total life cycle costs and minimal additional construction costs, while ensuring healthier, more comfortable, and more resilient buildings. 

What is TEDI?

Thermal Energy Demand Intensity (TEDI) measures the heating and cooling demand of a building in kBtu/sf-yr. Heating TEDI is the total annual energy delivered to the building for space conditioning and conditioning of ventilation air. Cooling TEDI is the total annual energy removed from the building for space conditioning and conditioning of ventilation air.

Can buildings still have gas cooktops, water heaters or other appliances along with all-electric heating and cooling under the Specialized Code? 

Yes, but this will make the building a “mixed-fuel” building, requiring pre-wiring for future electrification and on-site renewable energy offsets. 

Are emergency generators allowed?

Yes, fossil fuel powered emergency generators are allowed for all building sizes and types. 

Why is there a pre-wiring requirement?

The Specialized Code was developed to be consistent with the Commonwealth’s net-zero by 2050 goals. Wiring for electrification is easy and low cost at the time of construction but becomes expensive and time-consuming after construction. The pre-wiring requirement protects against high consumer costs for future retrofits, which will be necessary to meet the Commonwealth’s climate goals.

How much solar is required for residential buildings using fossil fuels?

One- and two- family dwellings and townhouses that use fossil fuels must install at least 4kW of solar per dwelling unit, except when the potential solar zone area (refer to code for definition) is less than 300 square feet. Other low-rise residential buildings that use fossil fuels must install on-site solar PV system with a rated capacity of not less than 0.75 W/ft of the gross conditioned living area, except when the Potential Solar Zone Area (refer to code for definition) is less than 300 square feet or when the building has a permanently installed domestic solar water heating system with a minimum solar savings fraction of 0.5.

My residence is surrounded by trees – do I have to cut down trees to meet the onsite solar requirements?

There are exceptions to the onsite solar requirements:

• Roof area oriented between 110 degrees and 270 degrees of true north of new one-and two family homes and townhouses is under 600 square feet.
• Roof area is in full or partial shade for more than 70 percent of daylight hours annually.

How much solar is required for commercial buildings using fossil fuels?

New buildings that fall under the commercial code and use fossil fuels must install on-site renewable energy with a rated capacity of at least 1.5 W/ft of the gross conditioned floor area of the three largest floors. Where the building site cannot meet the requirement in full with an on-site system, the building site shall install a partial system sized to at least 75% of the Potential Solar Zone Area (refer to code for definition).

Are there additional EV charging requirements in the Specialized Code?

No, there are no additional EV charging requirements beyond the Stretch Code requirements.

If you have additional questions about the Stretch Code or Specialized Code, check out DOER’s list of FAQs.