NYC 2020 Energy Conservation Code: Building Envelopes

NYC 2020 Energy Conservation Code: Building Envelopes

By John Lashley

As previously reported, the New York City Energy Conservation Code (NYCECC) has been updated to conform with the 2020 Energy Conservation Construction Code of New York State (ECCCNYS).

This article highlights new building envelope requirements for commercial buildings.

Building Envelopes: Commercial Provisions

C401.2.1. “Application to replacement fenestration products” has been replaced with “Application to Group R-3 Buildings.”

Result: Portions of existing fenestration product no longer have a path for compliance. Glass-only replacement in existing sashes and frames is allowed per C504.2(1) as a repair.

Table 402.1.3. “Opaque Thermal Envelope Insulation Component Minimum Requirements R-Value Method” now has more stringent requirements, with the exception of “Opaque doors.”

Result: This change increased the thickness of currently available insulation.

Table C402.1.4. “Opaque Thermal Envelope Assembly Maximum Requirements U-Factor Method” also has more stringent requirements. Exceptions include:

  • Roofs – Metal buildings
  • Walls, Below Grade – Below-grade walls
  • Floors – Joist/Framing

In addition, a garage door classification was added to “Opaque doors.”

Result: The changes increased the thickness of currently available assembly materials.

C402.1.4.2. “Thermal resistance of mechanical equipment penetrations” has been replaced with “Thermal resistance of spandrel panels.” A new section with a related table has been added.

Result: The updated code provides a new compliance path for spandrel panels.

C402.2.1. “Multiple layers of continuous insulation board” has been replaced with “Roof assembly.” New language has been added regarding insulation installed in the cavity of a suspended ceiling with removable tiles. Also, new exceptions (#3 and #4) have been added.


    • Insulation between suspended ceilings with removable tiles and the roof slab no longer have a compliance path.
    • Tapering to roof drains no longer requires two layers of insulation.
    • Performance and U-Factor alternative is now allowed for roof insulation. This alternative requires insulation to have a minimum thickness of one inch.

C402.2.1.1. Skylight curbs are now required to be insulated—with one exception.


    • The change reduces the ability to site-build compliant skylight curbs.
    • Per the exception, skylight curbs as part of the skylight assembly are allowed.

C402.2.2. The section on “Above-grade walls” now includes language for integral insulation installed in CMU.

Result: The change creates a path of compliance for new CMU product/technique.

C402.2.7. “Fireplaces” have been replaced with “Airspaces,” and a new code section was added.

Result: The change creates a path of compliance for unventilated cavities in the building envelope.

C402.3.1. This section adopts a new reference standard.

Result: CRRC-1 replaces CRRC-S100.

C402.4.1.2. “Increased skylight area with daylight responsive controls” has increased the skylight area from 5% to 6% of the roof area.

Result: This change will need to be considered when including skylights.

Table C402.4. “Building Envelope Fenestration Maximum U-Factor and SHGC Requirements” now has more stringent requirements. In addition, new fenestration types have been added, and new compliance requirements are in effect for assemblies in building more than 95 feet above the curb.


    • Currently available product may not meet the new requirements.
    • Assemblies more than 95 feet above the curb now have relaxed compliance requirements.

C402.4.4. “Doors” have been replaced with “Daylight zones.” A new code section was added and existing code sections adjusted.

Result: New code compliance requirement refers to the Electrical Power and Lighting Systems Section.

C402. Under “Materials,” Item 16, “Solid or hollow masonry constructed of clay or share masonry” has been removed.

Result: Solid or hollow masonry is no longer permitted for air barrier compliance.

C402.5.1.3. The section on “Air barrier testing” has been rewritten to include new buildings and additions of 10,000 square feet or greater.

Result: More existing buildings must now meet this requirement.

Table C402.5.2. “Maximum Air Leakage Rate For Fenestration Assemblies” now includes power operated sliding and folding doors.

Result: Currently available products may not meet the new requirements.

C402.5.3. “Rooms containing fuel-burning appliances” no longer allows direct vent appliances as an exception. All rooms containing fuel-burning appliances with direct vents need to apply.

Result: Industry/MEP engineers must include a path for compliance in all schematics.

C402.5.7. Under “Vestibules,” exception #7 (“ . . . doors that have an air curtain . . . ”) has been removed.

Result: Removing the air curtain option makes this requirement more stringent.

C402.6. A new code section was added under “Thermal Bridges.”

Result: The change adds a new code compliance requirement for balconies, shelf angles, parapets, and any horizontal or vertical break in the building envelope.

If you have any questions about how these changes affect your projects, please call Metropolis Group at 212.233.6344.