Stretch Code Updates Pending

DOER has issued updates to the current stretch and opt-in specialized code. These have been out for public comment for some time. The latest news is that they will become effective on February 14, 2025. Most of the changes are minor, but you should note a few important ones. The updates clarify district energy systems' role in decarbonization efforts. They also streamline the requirements regarding when a change of use triggers whole-building compliance and permit projects to navigate those troublesome existing thermal bridges in buildings undergoing renovation. In the specialized code, the required amount of day one solar PV is reduced for projects pursuing the future electrification pathway.Significant changes to the Commercial Stretch Code and Specialized Code:

1. District Energy Systems (DES): the updates include new definitions for DES. Systems can obtain an Order of Conditions from the DOER indicating the acceptance of a decarbonization plan. So long as the DES system maintains that order of conditions, buildings supplied with heating from the approved DES can meet the partial and future electrification requirements of the Stretch and Specialized Code. This means that campuses will be able to transition their DES over time rather than having new buildings that are forced to disconnect from the campus loop. It may also provide a pathway for existing steam utilities, although the DOER notes that no DES systems have been approved yet.
2. Passive House permit flexibility: A project can get a temporary Certificate of Occupancy before the final Passive House certification is complete.
3. Flexibility around existing building renovations: 
   1.  For minor renovations that include localized removal of interior finishes, “exposed wall cavities shall be filled with insulation not less than R-4/inch”. Prior language had suggested that any intervention triggered a complete envelope upgrade. This will allow common sense improvements for projects with minimal envelope scope.
   2. Thermal bridges due to existing wall components that are “unaltered and inaccessible” can be excluded in the thermal derating calculations. The connection between floor and wall in many older buildings is problematic. This change should allow these buildings to be renovated in a cost effective way, without being forced to “throw-away” a lot of embodied carbon.

Under the current code, we’ve seen several examples where an owners considers doing nothing since any improvements will trigger full compliance, making the project cost-prohibitive. With these changes, existing buildings can be renovated and improved in a cost-effective way, saving significant amounts of embodied carbon compared to the minimal operation savings full compliance might provide.

1. Clarification to the Change of Use language: The code has required that a change of use that increases energy consumption must fully comply with other elements of the code, as if it were new construction. The updates clarify that only fossil fuel use or total energy use should be compared.  A project switching from gas heat to heat pumps would not trigger the additional requirements so long as the total energy consumption does not increase. Additionally, the updates clarify that modeled energy consumption shall be used for both sides of the comparison – you can’t compare a model for the new building against the utility bills of the existing, or vice versa.
2. Reduction in Rooftop PV requirements: Projects under the Specialized Code following the future electrification pathway are required to install photovoltaics (PV) as part of the initial construction. Many projects following this pathway have found that there was simply no room for enough PV to meet the requirements, especially after accounting for other present and future mechanical equipment the code requires. The update reduces the amount of PV by 67% to only 0.5 W/sf (compared to the previous requirement of 1.5 W/sf)

Overall, these changes should remove a few pain points and lead to better projects being built. More details can be found on the DOER Stretch Code website.