H Window Timber Curtain Wall +

Declaration details

Manufacturer

The H Window Company

Program operator

Smart EPD

Declaration number

SmartEPD-2026-158-1124-01

Date of issue

October 27, 2026

Valid until

October 27, 2031

Product category rules (PCR)

NSF PCR for Fenestration Assemblies v2

Standard

ISO 14025:2006 and ISO 21930:2017

Declared unit

1 m2 of product of fenestration assembly, including frame and glazing

System boundary

Cradle to gate (A1 - A3)

Product specificity

Product Specific

Manufacturing specificity

Facility Specific

Manufacturing plant

The H Window Company, Ashland facility (800 Sum Road, Ashland, WI, USA)

Product category

Openings › CurtainWalls

Verifier

Sevda Alanya Rosenbaum

LCA software

CarbonGraph 2025.11.11.p02

Program instructions

Smart EPD General Program Instructions v.2.0, March 2025

Life cycle assessment results

Results per 1 m2 of product of fenestration assembly, including frame and glazing.

Environmental Impact Assessment Results

Resource Use Indicators

Waste and Output Flow Indicators

Carbon Emissions and Removals

ND = not declared. Life cycle modules: A1-A3 product stage, A4-A5 construction process, B use stage, C end of life, D benefits and loads beyond the system boundary.

Material composition

Hazardous substances

No regulated hazardous or dangerous substances are included in this product.

Product description

The H Window Timber Curtain Wall + is a stick-built timber, aluminum and glass curtain wall system for exterior building envelopes. It consists of timber mullions, extruded aluminum profiles, insulated glazing units (IGUs), gaskets, sealants, fasteners, hardware and installation and anchoring components that support and retain the glazing.

Results are declared for a reference configuration of 1.965 m x 1.980 m (3.891 m2) with three vertical mullions and four horizontal mullion segments, 56 mm x 160 mm softwood glulam mullions finished with varnish (no stain), aluminum profiles with 40% recycled content and a Kynar coating, and a 25.4 mm double-pane IGU with two 6 mm tempered glass lites and a 90% argon-filled cavity. This glazing configuration is used on 67% of H Window Timber Curtain Wall + projects. Results for other dimensions, mullion layouts, mullion sizes and mullion materials can be estimated with the scaling equation in this EPD; glazing results are declared separately so that a different insulated glazing unit can be substituted.

The product carries a 10-year limited warranty.

Interpretation

For the total system, A1 raw material supply accounts for 88% of TRACI v2.1 GWP 100 (7.76E+01 of 8.85E+01 kg CO2 eq), A2 transport for 5% and A3 manufacturing for 7%. A1 also dominates the other indicators: 82% of POCP, 87% of EP, 88% of AP and over 99% of ODP. The frame contributes 56% of GWP 100 (4.99E+01 kg CO2 eq) and the glazing 44% (3.86E+01 kg CO2 eq). The main contributors are flat glass production for the IGU, aluminum profile production and the timber mullions, followed by gaskets, sealants, hardware and installation components.

Results depend on configuration choices and on a few modeled inputs. A triple-pane IGU raises total-system GWP 100 by 21.3%. Aluminum recycled content was tested as a robustness check: 0% recycled content raises frame GWP by 21.3% and 100% lowers it by 32.0%, against the documented 40%. Laminated bamboo mullions raise frame GWP by 70.1% relative to glulam. Mullion width and depth, the hardwood glulam proxy, anodized aluminum and replacing the biomass electricity with the regional grid each change frame GWP by 2.0% to 4.3%. Powder coating, timber stain and a ±40% change in the estimated IGU components change results by 1.2% or less.