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Materials & Environmental Impact

Foam-free

Built without spray-foam or rigid-foam insulation — uses fiber, cellulose, mineral wool, or other low-impact alternatives.

Foam-free (placeholder seal) FF PLACEHOLDER

Description

The Foam-free badge recognizes homes built without spray-foam or rigid-foam insulation in the envelope assemblies. Spray foam and rigid foam are widely used because they perform well per inch, but their blowing agents have high global-warming potential, their flame retardants are persistent and bioaccumulative, and the foam itself is functionally non-recyclable at end of life. Foam-free assemblies use fiber, mineral wool, cellulose, hemp, sheep wool, or other low-impact alternatives that achieve the same thermal performance at the cost of slightly thicker walls.

The badge does not prohibit incidental foam (e.g. weatherstripping, factory-foamed window sashes, small can-foam at penetrations). It prohibits foam as the primary insulating layer in the wall, roof, floor, foundation, and basement assemblies.

Required standard requirements

To earn this badge, the project must meet all of the following existing GreenStar requirements:

Additional badge criteria

Beyond the required standard requirements above, the project must also satisfy:

Excluded products (as the primary insulation)

  1. 01.

    Open-cell and closed-cell spray polyurethane foam (SPF) — not permitted as wall, roof, or floor insulation.

  2. 02.

    Rigid foam boards — extruded polystyrene (XPS), expanded polystyrene (EPS), and polyisocyanurate (polyiso) — not permitted as continuous exterior insulation, foundation insulation, or sub-slab insulation.

  3. 03.

    Spray-applied foam at the rim joist, attic-floor air-seal layer, or basement-wall continuous layer.

Permitted alternatives

  1. 01.

    Dense-pack or blown cellulose (recycled newsprint).

  2. 02.

    Mineral wool batts or boards (Rockwool, Owens Corning Thermafiber) — including for continuous exterior insulation and sub-slab applications (mineral wool sub-slab is climate-zone-dependent; verify moisture strategy).

  3. 03.

    Fiberglass batts (high-density, formaldehyde-free preferred).

  4. 04.

    Biobased options: hemp insulation, sheep wool, wood-fiber boards (Gutex, Steico, Hempitecture), cork.

  5. 05.

    Foamed-glass aggregate (Glavel, Foamglas) for sub-slab and frost-protected shallow foundation applications.

Acceptable incidental foam

  1. 01.

    Factory-applied foam in window/door frames, garage-door panels, and refrigeration appliance insulation.

  2. 02.

    Single-component can foam used in volumes < 0.5 cu ft per project for sealing penetrations and gaps not addressable by other sealants.

  3. 03.

    Foam weatherstripping, foam tapes (e.g. EPDM gasket tape), and foam-backer rod at joints.

Performance equivalence

  1. 01.

    Foam-free assemblies must meet the same effective whole-assembly R-value as the project would have achieved with foam, calculated using parallel-path or two-dimensional thermal modeling (THERM, WUFI, or equivalent) accounting for thermal bridging at framing.

  2. 02.

    Where wall thickness becomes a constraint (urban infill, lot-line construction), double-stud or staggered-stud framing is the recommended path to high R-value without foam.

Documentation

  1. 01.

    Insulation schedule listing each assembly (foundation, slab, wall, rim joist, roof) with product, R-value, and thickness.

  2. 02.

    Product spec sheets / SDS for each insulation product, with foam-free designation visible.

  3. 03.

    Pre-drywall photos showing the installed insulation in each major assembly.

  4. 04.

    Whole-wall thermal calculation showing effective R-value parity with the comparable foam assembly.

Verification by tier

Evidence the project team submits at each certification tier. Cumulative — higher tiers include everything below unless noted otherwise.

  1. Certified

    Self-attestation
    • 01.

      Insulation schedule listing every assembly (foundation, slab, wall, rim joist, roof) with product, R-value, and thickness — none containing SPF, XPS, EPS, or polyiso as primary insulation.

  2. Silver

    Documents + photos
    • 01.

      Product spec sheets / SDS for each installed insulation product, with foam-free designation visible.

    • 02.

      Pre-drywall photos of installed insulation in each major assembly.

  3. Gold

    Third-party test
    • 01.

      Whole-wall thermal calculation (THERM, WUFI, or equivalent two-dimensional analysis) showing effective R-value parity with the comparable foam assembly.

    • 02.

      Third-party verification of incidental-foam volumes (< 0.5 cu ft can-foam project-wide).

  4. Platinum

    Post-occupancy verification
    • 01.

      Re-verification at the time of any future major renovation that the foam-free assemblies are not breached.

Energy & Climate Resilience Required from Silver GHI Zero Energy Certified GHI Zero Carbon Certified GHI Zero Energy Ready Certified Foam-free

Home Energy Performance

DOE Home Energy Score (existing) or modeled annual energy use (new construction). Alternative tools include HERS, PHPP, WUFI Passive, BeOpt, and 90.1.

Spec by tier

TierSpec
CertifiedNot required at this tier
SilverDOE Home Energy Score of 6
GoldDOE Home Energy Score of 8
PlatinumDOE Home Energy Score of 10 (existing) — or 17.5 MBtu/year (new construction)

Scope

Whole-house energy performance, rated using DOE Home Energy Score or an equivalent recognized rating tool.

Requirements

Performance targets

  1. 01.

    Engage a qualified DOE Home Energy Score assessor (or equivalent: HERS rater, PHIUS verifier) to score the home.

  2. 02.

    Score must meet or exceed the tier threshold in the "Spec by tier" table above. For new construction, the equivalent thresholds in modeled annual energy use (MBtu/year) apply.

  3. 03.

    Acceptable alternative scoring tools: HERS Index, PHIUS+, Passive House Planning Package (PHPP), BeOpt, ASHRAE 90.1 modeled output.

Documentation

Evidence the inspector / Institute will need.

  1. 01.

    DOE Home Energy Score report from a certified assessor — includes the score (1-10), label-style summary, and improvement recommendations.

  2. 02.

    OR equivalent: HERS Index report, PHIUS verification, PHPP output, or BeOpt modeling output.

Guidance

How the Home Energy Score scale works

DOE Home Energy Score is a 1-10 scale based on modeled annual energy use per square foot, normalized for local climate. A score of 5 represents the U.S. average existing home; a score of 10 represents the best 10% of homes nationally. The score is asset-based (not consumption-based), so it reflects the building itself rather than how the occupants use it.

Why one tier might map to several scores

A Gold-tier home (score 8) modeled at the local 99% design temperature lands in roughly the same actual annual consumption as a 17.5 MBtu/year new build — the standard accepts either pathway. Use whichever tool your rater is certified for; results are interchangeable for compliance.

Resources

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Materials & Environmental Impact Required from Certified GHI Zero Carbon Certified Foam-free Sustainable Materials

Embodied Carbon Reduction

Reduction in upfront embodied carbon below the 154 kg CO₂e/m² baseline. Approved tools: Beam Estimator, EC3, PHPP (PH Ribbon). Alternative pathways available at Silver (no concrete, RECs, solar offset, small home).

Spec by tier

TierSpec
CertifiedEmbodied-carbon evaluation required
Silver10% reduction from baseline
Gold15% reduction from baseline
Platinum30% reduction from baseline

Scope

Upfront embodied carbon (A1-A5 life-cycle stages) of new construction or major addition. Existing structure being kept in place is exempt by definition (zero new embodied carbon).

Requirements

Performance targets

  1. 01.

    At Certified: complete an embodied-carbon evaluation using an approved tool (Beam Estimator, EC3, PHPP / PH Ribbon). The evaluation must report total upfront kg CO₂e/m² for the project.

  2. 02.

    At Silver: reduce embodied carbon by at least 10% below the GreenStar baseline of 154 kg CO₂e/m².

  3. 03.

    At Gold: reduce by at least 15% below baseline.

  4. 04.

    At Platinum: reduce by at least 30% below baseline.

  5. 05.

    Alternative pathways accepted at Silver: build without concrete, OR purchase renewable energy credits equal to project embodied carbon, OR install solar PV offsetting embodied carbon over 30 years.

  6. 06.

    Small-home exemption: single-family ≤ 800 sf and multifamily units averaging ≤ 600 sf are exempt from the Silver+ percentage-reduction requirements (still complete the evaluation at Certified).

Documentation

Evidence the inspector / Institute will need.

  1. 01.

    Embodied-carbon report from an approved tool (Beam, EC3, PHPP) showing the project's upfront kg CO₂e/m² and the comparison to baseline.

  2. 02.

    Bill of materials including quantities (cubic yards of concrete, board feet of lumber, etc.) used in the calculation.

  3. 03.

    For alternative pathways at Silver: REC purchase certificate, solar system sizing calculation, or no-concrete design documentation.

Guidance

Why embodied carbon matters now

For a new high-efficiency home, embodied carbon (the carbon emitted to make the building materials) typically exceeds the operational carbon (heating/cooling/electric) for the first 30 years of the building's life. As the grid decarbonizes and homes become more efficient, embodied carbon becomes a larger share of total lifecycle impact. Choosing low-carbon concrete, wood-frame vs steel-frame, and reused materials makes a measurable difference.

The biggest reduction levers

Concrete is typically 30-50% of a home's embodied carbon. Switching from standard Portland cement concrete to a low-carbon mix (Type IL cement, fly ash or slag replacement at 30-50%, or specifying max OPC content) can cut concrete EC by 30-60% with no structural impact. Wood framing has dramatically lower EC than steel; insulation choice (mineral wool vs XPS foam) varies by 10x.

Resources

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