Corrections Log

Clear-wall (studs-included) R-values now come from one parallel-path calculation (src/lib/assembly.ts) rendered on every page, so the same assembly shows the same figure site-wide. A few displayed values shifted by 0.1 to 0.5.

Affected pages: r-value-chart, wall-insulation, rigid-foam-insulation, insulation-glossary. 2×6 R-21 + R-5ci clear-wall R-22.9 -> R-22.8; wall-insulation worked example (2×6 R-21 + R-5.6ci) R-24 -> R-23.5 and stud value R-6.88 -> R-6.76; rigid-foam gain bases 2×4 R-13 ~R-10.5 -> R-11.8 and 2×6 R-19 ~R-15.5 -> R-15.8 with dependent gains recomputed (about 95% -> 92%, 32% -> 35%, 21-26% -> 25-30%); glossary 2×6 R-23 wall about R-18 -> R-17.8. Values are rendered from the formula (the [[clearwall]] token / clearWallR helper), not typed in; canon's rounded 17.4/22.9 now print as the formula's 17.3/22.8.

Corrected hybrid-wall total R-value arithmetic, basement-wall code table (editions, Marine 4C grouping, R-13+R-5ci option), closed-cell 3-inch low end, and EPS/XPS foam R ranges; removed unsourced figures and dead/irrelevant links; added registry citations.

Hybrid total R-19-R-25 -> R-23-R-29 (FOAM-109, 3 locations); 3" closed-cell R-18 low end -> R-19 (FOAM-008); code table CZ4 split into "4 (except Marine)" R-10ci/R-13 and "4 Marine (4C), 5-8" R-15ci/R-19/R-13+R-5ci, CZ0-2 added, CZ3 Warm-Humid exception added, 2021 and 2024 IECC named (CODE-019)

Corrected crawl-space energy-savings, closed-cell and open-cell foam figures, XPS/EPS R-values and permeance, and the IECC crawl-space-wall code table; removed unsourced moisture/humidity/lifespan numbers and dead manufacturer/BSC/DOE links; added primary-source citations.

Energy savings "15–25%" -> measured 15% (floor) / 16% (wall) less total annual energy with cooling down 21%/36% (Advanced Energy NC study); closed-cell 2–3" assembly R-12–R-21 and subfloor R-14–R-21 -> R-12–R-22; XPS R-4.5–5.0/in -> R-5.0/in; XPS permeance ~1.1 perms/in -> ~1.2 perms/in (Class II); EPS permeance 2.0–5.0 perms/in -> ~2.6 perms/in (Class III); open-cell permeance 12–20 perms -> ≈23 perms (1"), ≈9 perms (2") Class III; rigid-foam wall option R-5–R-15 -> R-5–R-15 (XPS); R-3.6–R-13 (EPS); Zone 4 row split to "4 (except Marine)" R-10ci or R-13 and "Marine 4 (4C)" R-15ci/R-19/R-13+5ci (R-30 floor), CZ5–8 gain R-13+5ci option, named 2021 & 2024 IECC; removed "10+ gallons/day", "40–50% of first-floor air", RH "50–55%"/"below 60%"/"55–60%", fiberglass lifespans "2–5/1–3/3–7/5–7 years" and "80+ years".

Replaced the misattributed 15–25% "Advanced Energy" energy-savings claim with the actual study figures and ENERGY STAR's 15% primary, removed unsourced moisture/stack-effect/perm/RH numbers and IRC/DOE attributions, fixed the rigid-foam R-value range, and neutralised practitioner-voice copy.

energy savings "15–25%" (Advanced Energy, body) -> closed-crawl study: 15%/16% total energy, cooling 21%/36%, heating −11%/+2% (aceee); Table B energy-savings row "5–10% | 15–25%" -> row deleted; "15–25%" at payback/Key-Takeaways/FAQ -> ENERGY STAR avg 15% of heating & cooling; rigid foam "R-5–R-15 (XPS or EPS, 1–3 in)" -> XPS ~R-5/in = R-5–R-15 and EPS R-3.6–4.4/in = R-3.6–13.2 by thickness; "10+ gallons/day" -> removed; "40–50%" stack effect -> removed; "70–80%" barrier benefit -> removed; perms "<0.01 vs ~0.06" -> removed; dehumidifier "50–55% RH" -> removed

Corrected garage code R-value ranges to the 2021 IECC wood-frame-wall and floor rows, stripped unsourced door/fire numbers, and added primary-source citations throughout.

Shared-wall code R-value R-13 to R-21 (varies by zone) -> R-13 (CZ0-2) / R-20 (CZ3) / R-30 (CZ4-8) wood-frame wall row; ceiling-under-living R-19 to R-38 -> R-13 (CZ0-2) to R-38 (CZ7-8) floor row; floor "R-10 (if heated slab)" -> R-5ci under full slab + R-10ci slab-edge (CZ3 to 2 ft; CZ4-8 to 4 ft; CZ0-2 none); mineral wool "non-combustible to 2,150°F" -> noncombustible per ASTM E136 (2,150°F removed); uninsulated door "R-1" removed; DIY door panels "R-4 to R-8 / quadrupling to octupling" removed; pre-insulated doors "R-6 to R-12 / R-12 to R-18" removed; Type X "resists fire for one hour" / "20-minute" door rating removed

Corrected the example-city table and zone labels to the 2021/2024 IECC county map, relabeled zones by moisture regime, added nine primary-source citations, and added author plus a Last reviewed date.

Dallas TX 3 -> 2A (moved out of Zone 3 examples); Nashville TN dropped from Zone 4 (it is 3A); Boise ID dropped from Zone 6 (it is 5B); Phoenix AZ labeled 2B; Zone 1 examples -> Honolulu/Miami/Key West (1A); Duluth MN (not in registry) -> Aroostook County ME for Zone 7; zoneColors descriptive names (e.g. "Hot-Humid", "Cold (Severe)", "Subarctic") -> IECC number + A/B/C subzone labels; Marine 4 (4C) prose corrected to follow zone 5 values; "Most states span one or two zones" -> "41 of 50 states contain more than one IECC zone" (PNNL); "either of two zones" boundary note -> county-by-county single zone; heating/cooling-dominant zone-range labels removed.

Corrected climate-zone and code-edition prose on the R-value calculator, removed an unsourced attic/wall heat-loss figure, and added primary-source citations.

table footnote "last verified May 2026" removed -> states page uses 2021 IECC values and lists 2024 ceiling/floor/slab changes with adoption-varies note (CODE-027/TRUST-048); "Most US states span just one or two climate zones" -> "41 of the 50 states contain more than one IECC climate zone" (CODE-053); boundary "may fall into either of two zones (Raleigh/Reno/Boise)" -> county-by-county single-zone framing (CODE-055, FAQ CODE-031); Marine "share requirements with their primary zone" -> 3C tracks Zone 3 but 4C follows Zone 5 (CODE-051); ci "installed on the exterior of the framing" -> "continuous across the framing (interior or exterior)" (CODE-024); "building science experts often recommend exceeding minimums" -> ENERGY STAR retrofit levels equal 2021 ceilings, exceed only older/2024 codes (CODE-108); walls "25-30% of heat loss" removed in client component context + mobile card (PHY-057); FAQ "heat rises, most heat escapes" -> stack-effect wording (PHY-057); added citations to R-value definition (PHY-001), 8-zones/R301.3 (CODE-033/CODE-038), and the 2021 Table R402.1.3 reference block

Replaced the fiberglass batt/blown rows with real manufacturer thicknesses, fixed the cellulose/fiberglass settling and polyiso cold-derating claims, corrected the quick-select labels to real IECC editions, and added sourced citations with a reviewed date.

Fiberglass batt row R-13 4.1in -> 3.5in, R-19 5.9in -> 6.25-6.5in, R-30 9.4in -> 9.5-10.25in, R-38 11.9in -> 12-12.5in, R-49 15.3in -> 13.5-14in, R-60 18.8in -> 18.75-20.5in (two stacked batts); blown-in fiberglass R-13 5.2in -> 4.75-5.25in, R-19 7.6in -> 6.75-7.5in, R-30 12.0in -> 10.4-11.5in, R-38 15.2in -> 13-14.5in, R-49 19.6in -> 16.4-18.25in, R-60 24.0in -> 19.75-21.75in; cellulose settling "~20%" -> initial-to-settled ~10% and 6-10% R-value loss (ORNL), derating row -15 to -20% -> -6 to -10%; blown-fiberglass settling 1-3% -> ~1% or less; polyiso cold derating -15 to -25% -> -12% at 40F, -27% at 25F (NRCA); quick-select labels R-30 "Zone 1-3" -> 2021 IECC zones 0-1, R-38 "Zone 4-5" -> 2024 IECC zones 2-3, R-49 "Zone 5-7" -> 2021 IECC zones 2-3, R-60 "Zone 6-8" -> 2021 IECC zones 4-8 (all imported from tool-constants.generated).

Corrected wall code minimums, replaced misattributed DOE energy-savings figures with sourced ENERGY STAR values, added a past-tense 25C note, removed unsourced field numbers, and added author, review date and inline citations to the quiz tool page.

Quiz wall/garage target R-value zones 4-8 20 -> 30 (cavity-only, now derived from IECC_CAVITY_R_2021 not hand-typed); wall code targets "Zones 3-4 R-20 or R-13+5ci" / "Zones 5-8 R-20+5ci or R-13+10ci" -> 2021 IECC per-zone strings (Zone 3 R-20 or R-13+5ci or R-0+15ci; Zones 4-8 incl. Marine 4 R-30 or R-20+5ci or R-13+10ci or R-0+20ci); basement "Zones 5-8 R-15ci or R-19" -> R-15ci or R-19 or R-13+5ci (Marine 4 grouped); "air sealing ... 15-25% on energy bills per DOE field studies" and quiz "15-25%/10-20%" -> ENERGY STAR average 15% of heating/cooling (7-20% by zone); R-19 batt "fills 2x6" -> noted it compresses to ~R-18, 2x6 filled by R-21 HD / R-23; removed rim-joist 0.5-1.0 ACH50, dense-pack "settle within a year / top 18 in empty", wall access-hole "2-3 in dia", garage door "R-12 to R-18", crawl "6+ mil ... non-negotiable" -> "check local code"; added "The federal 25C credit (30% of cost, up to $1,200/yr) ... installed Jan 1 2023 through Dec 31 2025 ... not allowed for property placed in service after Dec 31 2025"; added Marko Visic byline + "Last reviewed: October 28, 2026" + 18-source SourceList.

Removed the expired federal 25C tax credit from the math and copy, cited the retained figures, dropped unsourced heat-loss-share and "historical average" claims, and fixed the Fargo zone label.

25C credit removed from SavingsCalculator math (Math.min(cost*0.3,1200) adjusted-cost/adjusted-payback block deleted) -> past-tense note only; "Tax credits cut payback ~30%" callout + "2023-2032 Tax Credits Available" callout -> past-tense 25C note (expired for property placed in service after 2025-12-31), cited energystar-insulation / energystar-federal-tax-credits / irs-faqs-for-modification-of-sections-25c-25d-25e-30c-30d-45 / irs-i5695-2; "largest single source of heat loss" -> "largest area of potential heat loss by square footage" cited energycodes-becp-resource-guide-air-leakage; "About 50% of home energy ... bill" -> "about half of home energy use ... 52% of household site energy in 2020" cited eia-homes / eia-ce3-1 / energystar-mega-2; "Attics ~30%, walls ~25%, floors ~10%" heat-loss shares -> removed (no source; weightings labelled illustrative); R-11->R-38 ~71% / inverse-R statement cited ashrae-90-1-2022-ay-20241031 / ecfr-part-460; FAQ wall ranges "pre-1970 no insulation / 1970s-1990s R-11 to R-13 / newer R-13 to R-21" -> ENERGY STAR R-11 2x4 1970-1989 baseline only, cited energystar-methodology; Zone 7 (Fargo) -> Zone 6 (Fargo); added Marko Visic author + "Last reviewed: October 28, 2026" and a Sources list.

Corrected code-minimum claims and the expired 25C tax-credit note on the cost calculator, removed fabricated cost-method sources, and added sourced citations with author and review date.

FAQ 25C "30% up to $1,200 ... as of 2024" (presented as currently available) -> past-tense note that the credit covered installs Jan 1 2023 through Dec 31 2025 and is not allowed after Dec 31 2025, plus DOE Home Energy Rebates (no HEEHR dollar), cited ENERGY STAR + IRS FS-2025-05 + i5695 + DOE; card "Standard new-construction wall package, zones 1-3" -> R-13 cavity alone meets 2021 IECC only in zones 0-2 (zone 3 needs R-20/R-13+5ci/R-0+15ci); card "Zone 4+ baseline; pair with R-5ci zones 5+" -> R-21 cavity alone fails 2021 IECC zone 4+ (needs R-30/R-20+5ci/R-13+10ci/R-0+20ci); card "Code minimum for zones 4-8" -> R-60 is the 2021 IECC Table R402.1.3 minimum for zones 4-8, 2024 IECC lowers to R-49; card "Zone 5+ requirement" (basement) -> 2021 IECC R-15ci/R-19/R-13+5ci zones 5-8, R-10ci/R-13 zone 4; client "2024 National Avg" data-source label -> "Illustrative range"; removed fabricated "RSMeans Construction Cost Data (2024)", "contractor pricing surveys (n=500+)", retailer-MSRP source lines; "Take our quiz" -> "the quiz".

Corrected blown-fiberglass and cellulose R-per-inch, depth and bag-count physics, fixed IECC example-city climate zones and added the 2024 IECC column, removed DOE/air-sealing-alone misattributions and unsourced figures, and neutralised practitioner voice.

Blown fiberglass R-2.2–2.7/in -> R-2.5–3.0/in; cellulose settling ~20% -> ~10% (labelled at settled density); fiberglass settling 1–3% -> about 1% or less; cellulose install depth R-30 10.5–11"->9.1–9.9", R-38 13–14"->11.4–12.5", R-49 17–18"->14.5–16.1", R-60 20–22"->17.7–19.7"; cellulose bags/1,000 sq ft R-30 18–22->31–39, R-38 23–28->42–53, R-49 30–36->56–71, R-60 37–43->69–86; blown fiberglass depth R-30 11–14"->10.4–11.5", R-38 14–17"->13–14.5", R-49 18–22"->16.4–18.25", R-60 22–27"->19.75–21.75"; "30–50% more depth than cellulose" -> about 13–39% (≈25% avg); "30% more material for 63% more resistance" -> 68–78% more cellulose for 63% more resistance; Dallas Zone 3 -> Zone 2, Indianapolis Zone 5 -> Zone 4, Duluth/International Falls removed and Anchorage added to Zone 7–8; Quick Answer "R-49 to R-60" -> full R-30/R-49/R-60 split plus 2024 IECC R-30/R-38/R-49; R-38/R-49 "~15%/~25% more savings" -> ≈20%/≈38% ceiling heat-flow reduction; removed 15–25% air-sealing-alone/DOE claim, "$2,000/year" bill, "140°F"/"10–25%" duct loss, "0.35 ACH50", "R-12" compressed-batt, "15–20%" HVAC gain; energy bill share "50–70%" -> 52% of household energy use (EIA RECS 2020).

Removed fabricated DOE attributions, unsourced savings percentages, and dead outbound links from the attic insulation cost guide, and cited the real primary sources for the energy-savings, code, and spray-foam figures.

"DOE estimates ... saves 10–20% / combined 15–25%" -> ENERGY STAR 15% avg of H&C (7–20% by zone, package of air sealing + insulation); rebates/tax credits "offset 10–30% of project costs" -> 25C 30% up to $1,200/yr for installs through 2025-12-31, DOE Home Energy Rebates, ENERGY STAR does not administer; "50–70% of the average US energy bill (~$2,000/yr)" -> 52% of U.S. household energy use (EIA RECS 2020), $2,000 base removed; "DOE estimates" R-19→R-49 attribution -> removed (dollar figures held); spray-foam open-cell R-19 to R-23 -> R-19 to R-21 (5.5 in); spray-foam closed-cell R-21 to R-30 -> R-19 to R-22 at 3 in, ~R-32 to R-37 at 5 in; vermiculite abatement $3.00–$8.00/sq ft -> cost not estimated + EPA guidance; FAQ code targets now name both 2021 and 2024 IECC

Corrected blown-in coverage and settling figures, cellulose bag counts, attic-hatch and compression R-values, code-table editions, and removed the misattributed DOE air-sealing savings claim.

Blown fiberglass R-2.2–2.7/in -> R-2.5–3.0/in; fiberglass depth for R-49 ~20" -> ~16.5–18"; fiberglass coverage depths R-30 11–14"->10.4–11.5", R-38 14–17"->13–14.5", R-49 18–22"->16.4–18.25", R-60 22–27"->19.75–21.75"; cellulose bags/1,000 sq ft R-30 18–22->31–39, R-38 23–28->42–53, R-49 30–36->56–71, R-60 37–43->69–86; cellulose install-depth header "+20% for settling" and depths R-30 10–11"->9.1–9.9", R-38 13–14"->11.4–12.5", R-49 16–18"->14.5–16.1", R-60 20–21"->17.7–19.7"; cellulose settling ~20% (over-install 20–25%) -> ~10% built into chart (~11% over-fill); fiberglass settling 1–3% -> ~1% or less; "DOE ... air sealing alone saves 15–25%, more than the insulation itself" -> ENERGY STAR combined ~15% of heating & cooling (7–20% by zone); "15–25% of savings unrealized" -> removed, reworded to ENERGY STAR combined figure; attic hatch 2" rigid foam "R-8 to R-10" -> named foams (2" XPS ~R-10, EPS R-7.2–8.8, foil-faced polyiso up to R-13.1), two layers "R-16 to R-20" -> doubled per foam; "compressed insulation loses R-value proportionally" -> loses less than proportionally (R-19 at 5.5" ~R-18; R-19 at 3.5" ~R-13); code table given 2021 AND 2024 IECC columns (2021 CZ0-1 R-30/CZ2-3 R-49/CZ4-8 R-60; 2024 CZ0-1 R-30/CZ2-3 R-38/CZ4-8 R-49) with full eaves-exception note; attic summer temp "130–150°F" removed.

Replaced the unsourced DOE "air sealing alone saves 15–25%" savings claim with the sourced ENERGY STAR combined figure, removed fabricated field and code/temperature numbers, and fixed dead/mislabeled outbound links.

"air sealing alone reduces heating and cooling costs by 15–25% (DOE)" -> "sealing plus insulation save an average of 15% of H&C costs, 7–20% by climate zone (ENERGY STAR)"; FAQ "15–25% alone + another 10–15% = full 15–25% combined" -> single ENERGY STAR 15%/7–20% combined figure; "We find them in about 70% of pre-2000 homes" -> removed; "attics reach 130–150°F" -> "attics get dangerously hot"; "reduce attic air leakage by 10–15%" and "20–40 wire holes" -> removed; "seal 50 small penetrations ≈ a 4"×4" hole" -> removed; "CFM50 ... at 50 Pascals" -> "total air leakage"; "3-inch clearance" / "2 inches for masonry chimneys" / "sealant rated to 500°F+" -> local-code / manufacturer-spec wording; DIY "captures 70–80% of the benefit" -> removed; dead energy.gov and buildingscience.com links removed; blower-door anchor repointed to energystar-mega; mislabeled "fire safety guide" and "signs of poor insulation" anchors fixed; self-link "air sealing vs. insulation" removed

Corrected blown-in R-per-inch, depths, bag counts, settling and air-sealing savings to manufacturer and ENERGY STAR sources; labeled IECC editions; removed a dead Home Depot link, an irrelevant DOE link, and the unsourced $2,000/year bill base.

Fiberglass R/in R-2.2–2.7 -> R-2.5–3.0; cellulose settling ~20% -> ~10%; fiberglass settling 1–3% -> ~1%; cellulose bags/1,000 sq ft R-30 18–22 -> 31–39, R-38 23–28 -> 42–53, R-49 30–36 -> 56–71, R-60 37–43 -> 69–86; fiberglass bags R-49 25–35 -> 22.2–23.5; fiberglass depth R-30 11–14" -> 10.4–11.5", R-38 14–17" -> 13–14.5", R-49 18–22" -> 16.4–18.25", R-60 22–27" -> 19.75–21.75"; cellulose install depth R-30 10–11" -> 9.1–9.9", R-38 13–14" -> 11.4–12.5", R-49 16–18" -> 14.5–16.1", R-60 20–21" -> 17.7–19.7"; cellulose over-install "20–25%" -> ~11% (bag chart initial); air-sealing "saves 15–25% on energy bills" -> ENERGY STAR ~15% of heating & cooling (7–20% by zone); removed unsourced "$2,000/year bill = $300–$500/year"; added 2024 IECC note (R-38 zones 2–3, R-49 zones 4–8) alongside 2021 IECC values.

Corrected the 2021/2024 IECC zone-4 wall minimums, replaced invented whole-wall percentages with assembly.ts clear-wall R-values, removed unsourced figures and dead links, and stripped practitioner first-person voice, adding primary-source citations throughout.

CZ4 wall minimum "R-20 or R-13+5ci" -> "R-30 or R-20+5ci or R-13+10ci or R-0+20ci" (2021 IECC, unchanged 2024); CZ0–2 added "R-0+10ci"; CZ3 added "R-0+15ci"; CZ5–8 added R-30 cavity-only option; ci reframed from "required" -> "one compliance option"; 2×4 R-13 ~R-10.5 -> ~R-11.8 clear-wall; 2×6 R-19 ~R-14.5 -> ~R-15.8; 2×6 R-21 ~R-15.5 -> ~R-17.0; 2×6 R-23 ~R-16.5 -> ~R-17.8; 2×6 R-19+R-5ci ~R-19.0 -> ~R-21.3; 2×4 R-13+R-10ci ~R-21.0 -> ~R-22.6; 2×6 R-21+R-5ci "~R-19" -> ~R-22.8 clear-wall; blended walkthrough "R-24–R-25" -> ~R-24; wood conducts "3–4×" -> "2.5–3.5×"; masonry R-0.20/in labelled common brick (face brick ~R-0.11–0.12/in) and removed the "1.5–2in foam = R-10 to R-20+" claim; Grade III "30%+" credited to BSC/RESNET -> measured ORNL/JM figures; removed steel "400×"/"58–68%"/whole-wall R estimates, "2,150°F+", "NRC 1.0+/1.00–1.05", injection-foam "R-12–R-14", "10–15% of US energy use", "exceed 15% heating savings", and the "19–28%/26%/23%" framing percentages

Corrected rigid-foam R-ranges to foam type and thickness, fixed thermal-bridging and whole-wall figures against lib/assembly.ts, re-attributed energy-savings and rebate claims from DOE to ENERGY STAR/IRS with citations, removed unsourced percentages and figures, and neutralised first-person practitioner voice.

exterior rigid foam "R-5 to R-13" -> EPS R-3.6-8.8 / XPS R-5-10 / foil-faced polyiso R-6-13.1 (75°F label); interior rigid foam "R-5 to R-15" -> polyiso R-6-13.1 (1-2 in.) / XPS ~R-15 (3 in.); dense-pack 2x6 "R-19-R-21" -> R-20-R-21; thermal-bridging "loses 19-24%" -> clear-wall R-11.8 for an R-13 2x4 cavity (studs included), whole-wall lower; comfort/FAQ "R-4 -> R-16+" -> about R-4 whole-wall -> about R-12 whole-wall; "DOE ... saves 15-25%" -> ENERGY STAR avg 15% of heating & cooling (11% of total), 7-20% by zone; rebates "offset 10-30%" (ENERGY STAR) -> 25C credit 30% up to $1,200/yr for 2023-01-01 to 2025-12-31 + DOE Home Energy Rebates (IRS/DOE/ENERGY STAR cited); removed unsourced "25-35% heat loss", "15-20%/5-10%", "10-15%", "30-40% air leakage", injection "R-12-R-14"/"Settling: None", "90% performance at 60% cost", "2-5% settling", DIY "1.5/3/4.0 lb/ft3, top 18 in, within a year", "~35x liquid volume", home-value "3-5%", and the "$2,000/year -> $200-$400/year" sentence

Reattributed radiant-barrier performance claims from "DOE" to the actual primary sources (ASTM C1313, ORNL/FSEC, ENERGY STAR), removed unsourced figures, fixed dead/irrelevant links, and labeled IECC code minimums by edition.

attic heat gain "25–40% (DOE data/research)" -> "16–42% reduction in summer ceiling heat gain, not a bill reduction (ORNL/FSEC)"; reflect "90–97% (DOE data)" -> emittance 0.03–0.10 / ~90–97% under ASTM C1313, ORNL assumes ≤0.05 clean; insulation+air-sealing "15–25% per DOE estimates" -> ENERGY STAR avg ~15% of heating & cooling (≈11% of total), 7–20% by zone; attic "20–30°F cooler" and ducts "150°F → 120–130°F" -> removed (no source), reworded to ORNL leaky-attic-duct benefit; heating benefit "1–2%" -> "little or no heating benefit (DOE)"; dusty-foil emittance "0.90" and "1–2 / 3–5 / 10-year" timeline -> ORNL "loses ~half its effectiveness over about 1–10 years"; bubble-wrap "R-1 to R-1.5" and "FTC has challenged/warnings" -> removed, replaced with 16 CFR 460.12 air-space/heat-flow labeling and Reflectix R-6.0 (down) vs R-2.0 (up); roof "150–180°F" / attic "150°F" and ceiling-load "15–25%" and "5–10× savings per dollar" and "R-38+" threshold -> removed (no source); code "R-30 to R-60 by code" -> "2021 IECC Table R402.1.3: R-30 (CZ0–1) / R-49 (CZ2–3) / R-60 (CZ4–8); 2024 IECC R-30 / R-38 / R-49".

Corrected fiberglass R-per-inch, blown-in depth/density/settling, batt thickness, compression and code-minimum figures to primary sources; removed unsourced fire/acoustic/IARC/service-life numbers and fabricated-inspection and misattributed-performance claims; fixed dead/irrelevant outbound links and added citations.

R-49 batt 15–16" -> 14" (13.5" JM), ~R-3.06–3.27/in -> ~R-3.5–3.6/in high-density; blown-in attic R-2.2–2.7/in -> R-2.5–3.0/in; wall dense-pack R-3.7–4.3/in -> R-4.0–4.3/in; 18–22" = R-44 to R-49 -> about R-49 to R-60+; blown-in density ~1 lb/ft³ -> about 0.45–0.5 lb/ft³ at R-30; blown FG settling 1–3% -> about 1% or less; cellulose settling ~20% -> ~10%; R-19 in 2×6 treated as full R-19 -> ~R-18 in a 5.5" cavity; R-25 in 2×8 note added ~R-23.6 compressed; std->HD 2×6 gain +10.5% -> +17%; Grade II "up to 2% void" -> no more than 15% (none deeper than 3/4 in.), Grade I/III aligned to ANSI/RESNET/ICC 301-2014 Add. F-2018 App. A; "30% or more / performs like R-13" -> measured 14–35% loss (ORNL/Navy/BRANZ); R-30 compressed to 5.5" ≈R-22/27% -> ≈R-21/30%; CZ4 wall "R-20 or R-13+5ci" -> R-30 or R-20+5ci or R-13+10ci or R-0+20ci (R-21 cavity alone non-compliant in CZ4), CZ3 adds R-0+15ci; kraft "zones 4+" -> climate zones 5, 6, 7, 8 and Marine 4; air-sealing "15–25% of savings" -> ENERGY STAR ~15% of H&C (~11% of total); removed R-30-in-3.5" ≈R-11/63% row, plumbing 25–40%, mineral wool 2,150°F, fiberglass 1,300°F / 1,300–1,500°F, NRC 1.0+/0.85–0.95, IARC 1988/2001 + "asbestos-free after 1980", recycled content 80% vs 40–60%, effective life 15–30/15–20 years.

Corrected the 2021/2024 IECC zone-4 wall minimum, fixed density and R-value-gain figures, re-sourced the polyiso cold-loss claim, and removed unsourced fire/sound/perm/recycled numbers and practitioner-voice copy.

CZ4 (except Marine) wall "R-20 or R-13+5 (zones 3–4)" -> R-30 cavity or R-20+R-5ci or R-13+R-10ci or R-0+R-20ci (2021 and 2024 IECC), zone 3 split out with R-0+R-15ci option added; density "roughly 3× denser, ~8 lb/ft³" -> ComfortBatt >1.8 lb/ft³ (Comfortboard 80 ~8 lb/ft³); same-cavity R-gain "+21%" (2×6) -> +28% vs R-19 compressed to R-18, "+20%" (2×8) -> +27% vs R-25 compressed to R-23.6, "10–35%/10–21%" -> about 10–28%; Comfortbatt "averages ~R-4.2/inch" -> about R-4.0–4.3/inch per ComfortBatt TDS; polyiso cold loss "up to 25% (BSC)" -> ~12% at 40°F and ~27% at 25°F (NRCA/R-Shield); removed 2,150°F, 3,000°F, 1,300–1,500°F, 1,100–1,200°F, ~400°F, NRC 1.00–1.05, STC 43/45–52/55+/50+, ~30+ perms, Safe'n'Sound ~R-4.3 est., recycled ~37%/75%/80%, bundle 40 lb/15 lb — all unsourced.

Corrected cellulose settling and bag-count figures, de-attributed misstated DOE savings to ENERGY STAR, fixed the Class A fire definition, removed unsourced numbers, replaced dead links, and neutralised practitioner-voice copy.

attic bag counts per 1,000 sq ft R-30 18-22 -> 31-39, R-38 23-28 -> 42-53, R-49 30-36 -> 56-71, R-60 37-43 -> 69-86; loose-fill settling ~20% -> ~10%; over-install 20-25% -> ~11%; R-49 installed depth 17-18" -> 14.5-16.1"; 20 bags coverage 500-700 sq ft -> 280-360 sq ft at R-49; dense-pack R/inch R-3.5-3.8 -> R-3.6-3.8; 2x6 dense-pack R-19-21 -> R-20-21; blown fiberglass settling 1-3% -> about 1% or less; dense-pack air-leakage "30-40%/20-30% vs batts (BSC)" -> removed; "DOE air sealing saves 10-20%" and "DOE $200-$400/yr" -> ENERGY STAR package (avg 15% of heating & cooling, 7-20% by climate zone), $ magnitudes held; recycled content 80-85%/40-60%/~37%/0% -> removed; cellulose FSI<=25/SDI<=450 asserted -> softened to "manufacturers report Class A (ASTM E84)"; mineral wool "2,150F" and untreated newspaper "400F" -> removed; lifespan 80+/20-30/50+ yr -> removed; cellulose ~4-6 perms and fiberglass/mineral wool ~30+ perms -> removed

Corrected blown-in fiberglass and cellulose R-values, settling percentages, coverage/bag counts, and de-attributed the DOE savings claim to ENERGY STAR; removed unsourced figures and dead links; added primary-source citations.

loose-fill fiberglass R-2.2–2.7/in -> R-2.5–3.0/in; wall dense-pack fiberglass R-3.7–4.3/in -> R-4.0–4.3/in; dense-pack cellulose R-3.5–3.8/in -> R-3.6–3.8/in; cellulose attic settling ~20% -> ~10% (dry loose-fill); fiberglass settling 1–3% / 1–20% -> about 1% or less; cellulose over-fill 20–25% -> ~11% above settled (bag-chart initial depth); fiberglass attic depths R-30 11–14" -> 10.4–11.5", R-38 14–17" -> 13–14.5", R-49 18–22" -> 16.4–18.25", R-60 22–27" -> 19.75–21.75"; cellulose install-depth col R-30 10.5–11" -> 9.1–9.9", R-38 13–14" -> 11.4–12.5", R-49 17–18" -> 14.5–16.1", R-60 20–22" -> 17.7–19.7"; cellulose bags/1,000 sq ft R-30 18–22 -> 31–39, R-38 23–28 -> 42–53, R-49 30–36 -> 56–71, R-60 37–43 -> 69–86; "DOE air sealing alone saves 15–25%" -> ENERGY STAR air sealing plus insulation ~15% of heating & cooling (~11% of total); dense-pack air-leakage "30–40% vs empty cavities" (BSC) removed; cellulose fire "SDI ≤450" and recycled-content 80–85%/40–60% removed; dense-pack "2–5%" settling and service-life year figures (80+/50–80+/20–30 yr) removed

Corrected fire/sound/durability figures that had no primary source, fixed the Zone 4 wall-code logic and the overstated mineral-wool R-value advantage, and removed two dead outbound links.

MW density ~8 lb/ft3 "(3x denser)" -> >1.8 lb/ft3 (Comfortbatt batt); 2x6 MW advantage +21% -> +28% (R-23 vs R-19 batt at ~R-18 installed); 2x8 advantage +20% -> +27% (R-30 vs R-25 at ~R-23.6); range "15–21%" -> "about 10–28%"; FG R-19 in 2x6 relabelled ~R-18 installed; FG R-25 in 2x8 relabelled ~R-23.6 installed; "zones 3–4 require R-20 / R-23 meets code" split so CZ4 except Marine = R-30 or R-20+5ci or R-13+10ci or R-0+20ci (2021 and 2024 IECC, R-23 alone does not comply); RESNET "30%+ Grade I vs III gap" -> ORNL measured R-15.4 vs R-13.2 (~14%); removed unsourced 2,150°F, 1,300–1,500°F, 1,100–1,200°F, NRC 0.85–1.05, STC 36–52, "40%+ wet R-loss", "~30+ perms", C1338 "zero fungal growth", "40–60%/~37% recycled", "50+/15–30 yr effective life", "~40/~15 lb bundle", "15–20% of MW"; dead buildingscience.com and rockwool.com/sustainability links removed.

Corrected blown-fiberglass R-value and depth, cellulose settling and over-fill figures, replaced the RESNET Grade III loss claim with ORNL-measured values, removed unsourced dense-pack air-leakage/fire/recycled/NRC/lifespan numbers, re-attributed the DOE savings claim to ENERGY STAR, and added primary-source citations throughout.

blown fiberglass R/in R-2.2–2.7 -> R-2.5–3.0; blown fiberglass R-49 depth ~20" -> ~16.4–18.25" and R-60 ~25" -> ~19.75–21.75"; "43% more depth" -> "roughly 13–39% more (about 25% avg)"; R-49 batt "~16"" -> ~14" single HD batt or ~16" stacked standard; cellulose settling ~20% -> about 10% and fiberglass 1–3% -> about 1%; cellulose over-fill 20–25% -> about 11% initial-installed per bag chart; RESNET Grade III "30%+" loss -> ORNL R-19 wall R-15.4 careful vs R-13.2 worst-typical (~14%); dense-pack R/in R-3.5–3.8 -> R-3.6–3.8; removed dense-pack "30–40% air leakage reduction"; removed wet fiberglass "R-1 or less"; removed fiberglass melt "1,300–1,500°F" and glass "2,500°F+"; removed cellulose "FSI ≤25/SDI ≤450"; removed recycled "40–60% / 80–85%"; removed NRC and effective-lifespan numbers; DOE "15–25% on heating and cooling" -> ENERGY STAR "about 15% of heating & cooling (about 11% of total)"

Corrected blown fiberglass and cellulose settling/R-value figures, removed the misattributed Building Science Corporation installation-defect claim with measured ORNL/Navy/BRANZ data, dropped unsourced service-life and NRC numbers, replaced two dead outbound links, and added primary-source citations.

blown attic fiberglass R-2.2–2.7/in -> R-2.5–3.0/in; cellulose loose-fill settling ~20% -> ~10%; cellulose over-install 20–25% -> ~11% above settled (fill to bag chart initial thickness); blown fiberglass settling 1–3% -> ~1% or less; batt Grade III defect "30% or more / performs like R-13" credited to BSC -> ORNL hot-box ~14% (R-15.4 perfect vs R-13.2 worst-typical R-19 wall), plus Navy 34% and BRANZ 35%; dense-pack-wall cellulose settling 2–5% -> Minimal (Nu-Wool "will not settle"); removed service-life "80+ years / 20–30 years effective / 50+ year" (no registry source); removed unsourced "NRC 1.0+"; removed dead buildingscience.com and homedepot.com links

Corrected the moisture-sandwich code example and vapor-retarder class/perm figures, replaced three dead or irrelevant outbound links with sourced text, and added primary-source citations.

Moisture Sandwich "add R-41 to reach R-60 (current IECC for zone 5)" -> "add R-30 to reach R-49 (2024 IECC ceiling minimum for climate zone 5; 2021 IECC sets R-60, met by R-49 at full height over the top plates)"; Class I permeance "<0.1 perms" -> "0.1 perm or less"; Class II "0.1–1.0 perms" -> ">0.1 to 1.0 perm"; Class III "1.0–10 perms" -> ">1.0 to 10 perm"; XPS "at 2" is ~0.5 perms" -> "typically Class II at about 1.2 perm/inch, roughly 0.6 perm at 2 inches, still Class II"; foil-faced polyiso "<0.05 perms" -> "typically a Class I vapor retarder"; latex paint "~5 perms" and MemBrain "1–20 perms / 20+ perms" numbers removed (no primary source); "below 2.0 ACH50" removed

Replaced the misattributed/fabricated polyiso cold-derating table and unsourced figures with NRCA test data and registry-sourced values, removed first-person practitioner voice, fixed dead BSC/Owens Corning links, and added citations throughout.

polyiso cold loss "R-3.0–4.0 at 0°F (38–54% of label)"/"up to 46%"/"~62% at 25°F" -> "R-4.05/in at 25°F (−27%, NRCA)"; derating Table B 75/50/40/25/0/−15°F rows -> NRCA 110/75/40/25°F (R-4.98/5.56/4.91/4.05); EPS "R-3.6–4.4 unchanged at 0°F / air-blown / most stable" -> "R rises in cold (Type II ~4.8 at 25°F), no blowing-agent aging but below-grade moisture lowers R"; 2×6 R-19+R-5 ci "~R-19 whole-wall vs ~R-14.5" -> "R-21.3 vs R-15.8 clear-wall (studs incl.), ORNL R-13.7 whole-wall"; whole-wall ci gain "15–30%" -> "~21–95% depending on ci R and base wall"; re-siding "R-5 to R-10" -> foam-specific EPS 3.6–8.8/XPS 5–10/polyiso 5.6–13.1; 6-in SIP "~R-24" -> Premier R-15 (4.5")/R-23 (6.5"), ORNL R-13.93 whole-wall; above-deck polyiso "R-11 to R-26" -> "R-11.4–23.6 roof-board LTTR"; XPS perm "~1.0–1.1/in, 2" ~0.5 approaches Class I" -> "~1.2/in Class II, 2" ~0.6 still Class II"; EPS perm "2.0–5.0/in" -> "~2.6/in Class III"; foil-faced polyiso "<0.05 perms" -> "Class I (≤0.1 perm)"; EPS psi "10–25" -> "5–60 (Type XI–XV)"; IECC zones 5–8 "R-5ci+R-20 or R-10ci+R-13" -> full 2021/2024 set (R-30cavity / R-20+5ci / R-13+10ci / R-0+20ci); "Blue (Dow)" -> "Blue (DuPont)"; polyiso long-term "LTTR drift (minor)" -> "roof-board LTTR R-5.7–5.9/in"; removed unsourced pentane "GWP ~5", EPS "near-zero GWP", "15-minute thermal barrier", polyiso-sandwich "10–15%", "1.5 in. cold" -> "~1.2–1.4 in."

Replaced misattributed BSC cold-weather figures with sourced NRCA 2014 test data, corrected the XPS/EPS comparison and IECC continuous-insulation framing, removed unsourced numbers, fixed dead links, added citations, and stripped first-person installer voice.

polyiso cold-weather loss "38–50% / R-3.5–4.5 at 25°F, R-3.0–4.0 at 0°F (BSC)" -> NRCA −12% at 40°F (R-4.91/in), −27% at 25°F (R-4.05/in vs R-5.56/in at 75°F), 0°F rows deleted; temperature table "% of Label (R-6.0)" baseline -> % of 75°F NRCA value 5.56; NRCA "R-5.6 warm / R-5.0 cold" split -> single NRCA design value R-5.0/in (Jan 2016), BSC cold-climate R-5.0/in; XPS labeled "R-4.5–5.0" -> R-5.0 min (R-5.6 high-R); XPS vapor "~1.1 perms/inch" -> 1.2 perm/in (Class II); "2 inches provides R-11.2" -> 2 in LTTR ~R-11.4; re-roof "R-11 to R-26" -> LTTR ~R-11.4 to R-23.6; "R-5 ci requirement in zones 4–5 / R-10 ci in zones 5–8" -> continuous insulation reframed as one 2021/2024 IECC compliance option (R-30 cavity, or R-20+5ci, or R-13+10ci) in CZ4–8, not a requirement.

Corrected XPS R-value, cold-temperature and polyiso figures, aging and moisture claims, and the blowing-agent/GWP story to current sourced values, removed practitioner voice and dead outbound links, and added citations.

Labeled XPS per-inch R-4.5–5.0 -> R-5.0 at 75°F (ASTM C578); polyiso cold-loss "38–50%"/"drops 38%" -> R-4.05/in at 25°F mean (about 27% below 75°F, NRCA); XPS-vs-polyiso 25°F cell R-5.0 (stable) -> R-5.6 (FOAMULAR NGX 250); XPS-vs-EPS 75°F cell R-4.5–5.0 -> R-5.0; EPS long-term "Stable indefinitely" -> no blowing-agent aging but below-grade moisture lowers R (94% retained at 4.8% water); vapor "~1.0–1.1 perm/in, approaches Class I at 2 in" -> ~1.2 perm/in, ~0.6 perm at 2 in, remains Class II; aging "5–10% over 10–15 yr, R-4.5–4.7" -> generation-split (legacy HCFC ~R-4.5–4.65 vs current NGX 15-yr LTTR R-5.0), 5-year ~95% row removed; GWP "~1,430 (current, highest)"/HFO "GWP 1–3" -> HFC-134a 1,430 legacy only, current US products low-GWP (GreenGuard blend GWP <50).

Corrected EPS/GPS/polyiso R-values, removed fabricated "never derates / 0% forever" and first-person claims, replaced dead BSC/DOE links with sourced data, and added registry citations throughout.

EPS Type II R-3.8/inch -> R-4.0 (ASTM C578-23 min); grades table rebuilt to C578-23 minimums (Type XI 0.70pcf/R-3.1/5psi now lowest-density, Type VIII R-3.7 -> R-3.8, Type IX R-4.0/20psi -> R-4.2/25psi, Type XIV 2.0pcf/25psi -> 2.40/40, Type XV 2.5+pcf/40psi -> 2.85/60, R-4.4 -> R-4.3); GPS R-4.7-5.0/inch -> R-4.3-4.6/inch at 75°F; 2in GPS R-9.4-10.0 -> R-8.6-9.2 and 2in XPS "R-9.0-9.4 aged" -> R-10 label; GPS FAQ "24-32% more R/inch" -> +10-19% by type; polyiso cold "R-3.5-4.5 (-38%)" -> NRCA R-4.91/in at 40°F (-12%) and R-4.05/in at 25°F (-27%), 0°F/-15°F rows dropped; XPS long-term "R-4.5-4.7 (-5-10%)" -> NGX LTTR R-5.0/in vs legacy HCFC -7-10%; EPS "0% - no change / day 10,000 forever" -> 94% of spec at 4.8% water (15-yr EPSMA) with below-grade moisture caveat; EPS cold "minimal variation / no change" -> R rises +8-14% as mean temp falls; XPS blowing agent "HFC-134a GWP 1,430 (Highest)" -> legacy-only with current reformulated products (GreenGuard GG25-LG <50 GWP, DuPont HFC-compliant); vapor perm "2.0-5.0 perm/in" -> 2.6 perm/in (Class III); removed EPS "~300°F+", "2-5% / <0.3% by volume", polyiso "GWP ~5", 45-55°F ground temp, and R-0.7/inch gap figures.

Corrected rigid-foam R-values, compressive-strength grades, moisture and blowing-agent claims, the IECC continuous-insulation requirement, and removed fabricated first-person/client framing, adding primary-source citations.

Labeled XPS R-4.5–5.0/in -> R-5.0/in at 75°F; XPS advantage over EPS "15–25%" -> about +14% to +39% by EPS type; EPS long-term "stable/no change/30+ years" -> no blowing-agent aging but below-grade moisture lowers R (EPSMA 94% at 4.8% water; OC R-1.74–3.36/in at 21 yr); EPS/XPS temperature "most stable/barely changes" -> both gain R as mean temp falls (EPS +8–14%, XPS +8% at 40°F/+12% at 25°F); compressive-strength table "Foamular 400/600/1000 = 60–100 psi" and EPS "10–25 psi / max standard 25" -> ASTM C578 by type (XPS 15/25/40/60/100; EPS 10/15/25/40/60, with 40=Foamular 400 Type VI); XPS vapor "~1.0–1.1 perm/in" -> 1.2 perm/in (Class II); EPS vapor "2.0–5.0 perm/in" -> 2.6 perm/in (Class III); XPS blowing agent "HFC or HFO transitioning (GWP <5)" -> HFC-134a (GWP 1,430) legacy, current Kingspan GG25-LG blend GWP <50 / DuPont HFC-compliant; 2021 IECC "requires R-5 ci in zones 5–8" -> errata-corrected Table R402.1.3 CZ4–8 "30 or 20&5ci or 13&10ci or 0&20ci", ci is one compliance path.

Corrected spray-foam permeance, R-values, code-compliance and GWP claims, removed unsourced figures and fabricated practitioner experience, re-attributed savings to ENERGY STAR, and added registry citations.

open-cell permeance "12–20 perms" -> "≈23 perms at 1 in., under 10 perms at 3.5 in.+ (Class III)"; closed-cell "<1 perm at 1"+ / built-in vapor barrier" -> "≈1 perm at 1 in.; Class II vapor retarder at ~1.5–2 in.+"; 2×4 closed-cell "R-21–R-24.5" -> "R-22–R-26"; 2×6 closed-cell "R-33–R-38.5" -> "R-35–R-41"; 2×6 fiberglass "R-19–R-21" -> "~R-18 (R-19 batt compressed)"; 2×8 fiberglass "R-25" -> "~R-23.6 (R-25 batt compressed)"; code claim "R-21–R-24.5 matches/beats 2021 IECC zones 5–8 (R-20+5ci)" -> "meets none of the Table R402.1.3 options (R-30 / R-20+R-5ci / R-13+R-10ci / R-0+R-20ci), 2021 and 2024 IECC; complies only via U-factor/performance path"; "DOE 15–25% insulation+air sealing" and "air sealing alone 10–20%" -> "ENERGY STAR average 15% of H&C, 7–20% by zone"; HFC "GWP 858" -> "older HFC (HFC-134a GWP ~1,430)"; HFO "GWP 1–3" -> "GWP under 1"; removed service life "80–100+ years", expansion "100×/35×", racking strength "250–300%", recycled content "80–85%/40–60%", HVAC efficiency "15–20%", "30–40%/20–30%" savings, DIY coverage "200–600 sq ft"/waste "20–30%"/tank "60–80°F/24h"/pass "½ in", cure/occupancy "24h/48–72h/24–72h", fiberglass "15–30 years", cellulose settling "~20%" -> "roughly 10%"; FSI/SDI "≤75/≤450" and "15-minute thermal barrier" -> worded requirement (IBC 2021 2603.4 / IRC 2021 R316.4); removed dead DOE, EPA Safer Choice, and buildingscience.com links plus the Honeywell/Chemours transition claim and the self-link

Corrected spray-foam permeance, closed-cell R-values, IECC compliance and GWP claims to sourced values, removed unsourced figures, and stripped fabricated practitioner voice.

open-cell permeance 12–20 perms -> ≈9 perms at 2" / under 10 perms at 3.5"+ (Class III); closed-cell "vapor barrier at 2"+" -> Class II vapor retarder (~0.5 perm) at 1.5–2"+; 2×4 closed-cell R-21.0–R-24.5 -> R-22 to R-26; 2×6 R-33.0–R-38.5 -> R-35 to R-41; 2×8 R-43.5–R-50.8 -> R-45 to R-54 (per-inch extrapolation); "R-21+ exceeds 2021 IECC CZ5-8 R-20+5ci from cavity fill" -> cavity-only R-22–26 meets none of R-30 / R-20+5ci / R-13+10ci / R-0+20ci (2021 & 2024 IECC); closed-cell max-R FAQ R-18 to R-28 -> R-19 to R-30; HFC GWP 858 -> "older HFC (high GWP)"; HFO GWP 1–3 -> very low GWP (under 1); lifespan 80+/80–100+ years -> removed; expansion ratio ~100×/~35× -> removed; racking strength up to 250–300% and ~250% uplift -> removed; FSI ≤75 / SDI ≤450 and "15-minute" barrier -> removed (worded requirement kept); NRC 0.70–0.80 / 0.50–0.70 / 1.00–1.05 -> removed

Corrected the outdated federal tax-credit framing, re-attributed the energy-savings figures from DOE to ENERGY STAR with sourced numbers, fixed roof-deck R-values, named the thermal-barrier code edition, and removed three dead/irrelevant outbound links.

IRA "provides up to $1,200/year ... through 2032" (present tense) -> 25C credit 30%/$1,200-a-year for materials installed 2023-01-01 to 2025-12-31, not allowed after 2025-12-31, plus DOE Home Energy Rebates; "DOE estimates ... 15–25%" -> ENERGY STAR average 15% of heating/cooling costs, 7–20% by zone; "heating and cooling 50–70% of the average US home energy bill (~$2,000/year)" -> space heating + air conditioning about 52% of U.S. household energy use ($2,000/year removed); open-cell roof deck "R-19–R-23 (5.5")" -> "R-19–R-21 (5.5")"; closed-cell roof deck "R-21–R-30 (3–5")" -> "R-19–R-22 (3"); ~R-32–R-37 (5")"; manufacturer "30–40%" and studies "20–30%" savings removed; "0.5–1.0 ACH50 reductions" removed; thermal barrier now cites IBC 2021 Sec. 2603.4 / IRC 2021 R316.4

Corrected material R-values, cold-temperature polyiso and settling figures, code-table wall minimums and example cities, relabeled thermal-bridging numbers as clear-wall, re-attributed air-sealing savings to ENERGY STAR, replaced two dead outbound links, and added primary-source citations.

Blown-in fiberglass per-inch R-2.2–2.7 -> R-2.5–3.0 (75°F); XPS per-inch R-4.5–5.0 -> R-5.0 labeled (3.5"=R-17.5, 5.5"=R-27.5); standard FG 5.5" cell R-19–20.4 -> R-16.5–20.4; Pro Tip blown FG 16–18" R-38–49 -> R-43–54; 2×6 5.5" "gives R-19" -> ≈R-18 (R-3.14/in = R-17.3); CZ4 wall "R-20 or R-13+5ci" -> R-30 or R-20+5ci or R-13+10ci or R-20ci; Dallas moved Zone 3 -> Zone 2; Duluth/International Falls -> Anchorage; ENERGY STAR retrofit "5, 6" -> "4C, 5, 6"; assembly ≈R-20 relabeled center-of-cavity R-19.9 + clear-wall R-17.3; R-23 wall "about R-18 whole-wall" -> R-17.8 clear-wall; "R-5 ci -> ~R-19, 27% over R-15" -> R-17.0 -> R-22.9 clear-wall; R-21+R-5 polyiso "whole-wall ~R-22" -> R-22.9 clear-wall; framing "3–4× faster" -> 2.5–3.5×; "cut heat loss by about 95%" -> 90–94%; cellulose "settles ~20%, install to 17–18"" -> dry loose-fill ~10%, R-49 initial 14.5–16.1"; FAQ blown-FG depths R-30 11–14"/R-38 14–17"/R-49 18–22" -> 10.4–11.5"/13–14.5"/16.4–18.25"; polyiso "lose up to 25% below 50°F (BSC)" -> NRCA R-5.56/in@75°F, R-4.91@40°F (−12%), R-4.05@25°F (−27%); air-sealing/insulation "DOE 15–25%" -> ENERGY STAR average 15% of H&C (11% total; 7–20% by zone).

Corrected cold-temperature R-values, cavity and thickness tables, the 2021/2024 IECC wall-code claim, and source attributions, removing fabricated figures and dead links and adding primary-source citations.

Polyiso cold R/in 25°F R-3.5–4.5 -> R-4.05 (−27%) and 40°F R-4.5–5.5 -> R-4.91 (−12%), "loses up to 25%" -> −12%/−27%; XPS 75°F R-4.5–5.0 -> R-5.0, XPS 25°F R-5.0–5.5 -> R-5.6 and 40°F R-4.8–5.2 -> R-5.4; EPS cold cells "unchanged R-3.6–4.4 / most stable" -> R-4.4–4.8 at 25°F, R-4.2–4.6 at 40°F (R rises in cold); fiberglass "stable across range" -> R rises as mean temp falls; closed-cell cavity 2×4 R-21–24.5 -> R-22–26, 2×6 R-33–38.5 -> R-35–41, FAQ R-21–24.5 -> R-22–26; 2×6 standard-FG cavity R-19–20.4 -> ≈R-18 (R-19 batt compressed); blown-in fiberglass R/in R-2.2–2.7 -> R-2.5–3.0; blown-fiberglass depths R-13 5–6"/R-19 7–8.5"/R-30 11–14"/R-38 14–17"/R-49 18–22"/R-60 22–27" -> 4.75–5.25"/6.75–7.5"/10.4–11.5"/13–14.5"/16.4–18.25"/19.75–21.75"; R-49 fiberglass batt 15–16" -> 13.5–14" single (R-60 relabeled as two stacked batts); cellulose settling ~20% -> ~10% (labeled R at settled density); re-siding foam "R-5 to R-13" -> per-material 1–2" EPS R-3.6–8.8 / XPS R-5–10 / polyiso roof-board R-5.6–11.4 / foil-faced polyiso R-6.0–13.1; CODE-011 "zones 5+ require cavity+continuous" -> 2021 IECC (and 2024) Table R402.1.3 allows CZ4C–8 R-30 cavity alone or 20+5ci/13+10ci/0+20ci; removed fabricated "10–15% polyiso-sandwich" gain; deleted blower-door/U-factor sentence; replaced dead BSC link with Info-502, removed irrelevant energy.gov link, re-pointed ENERGY STAR link to the R-values page.

Corrected polyiso, framing/whole-wall, RESNET-grade, IECC wall-code, temperature, and FTC-rule facts; removed unsourced figures and fabricated-inspection language; replaced three dead/irrelevant outbound links with registry-cited sources.

polyiso 1" board R-5.00 -> R-5.6 (assembly total R-28.54 -> R-29.14); polyiso cold loss "up to 25% below 50°F" (BSC) -> NRCA -12% at 40°F / -27% at 25°F; RESNET Grade II "up to 2% void" -> Grade I ≤2% / Grade II ≤15% (ANSI/RESNET/ICC 301); Grade III "30% or more / R-19 performs like R-13" -> removed, replaced with ORNL -14%, Navy/JM 34%, BRANZ 35%; framing loss "14-18%"/"15-19%" -> removed (parallel-path method); 2×4 R-13 ~R-10.5 -> R-11.8 clear-wall; 2×6 R-19 ~R-15.5 -> R-15.8; 2×6 R-21 ~R-17 -> R-17.0; 2×6 R-23 whole-wall ~R-18 -> R-17.8 clear-wall; R-23 + R-5ci ~R-19 -> R-23.8 clear-wall; R-21 + R-5ci whole-wall ~R-22 -> R-22.8 clear-wall; wood "3-4× faster" -> 2.5-3.5×; IECC CZ1-2 "R-13" -> R-13 or R-0+10ci, CZ3 add R-0+15ci, CZ4 "R-20 or R-13+5ci" -> R-30 or R-20+5ci or R-13+10ci or R-0+20ci (2021 IECC, same in 2024); DOE "air sealing alone 15-25%" (×2) -> ENERGY STAR combined 15% H&C / 11% total / 7-20% by zone; radiant barriers "zones 1-3" -> zones 1-2; R-0->R-19 "~95%" -> 90-94%, R-19->R-49 "half again" -> ~60% of remaining, R-49->R-100 "few percent" -> halves remaining (~1% of original); fiberglass "unaffected by temperature" -> R rises in cold (ORNL/NBS); removed unsourced "water 23× faster", "fiberglass loses 40%+ when wet", mineral-wool "unaffected", "sealed R-13 outperforms leaky R-21", house wrap "R-0.00" -> ≈R-0; FTC "tests at 75°F" -> requires manufacturers to test, ASTM list broadened to C177/C518/C1363/C1114, "not updated since 1979" -> amended since (latest 2019); FAQ test-unit BTU/(hr·ft²·°F) corrected as conductance with R = reciprocal

Replaced misattributed and unsourced R-values, permeance, settling, fire and savings figures with primary-sourced values and citations; removed dead/irrelevant outbound links and fabricated practitioner voice.

open-cell permeance "~10 perms at 3.5in" -> "23 perms at 1in, 9 at 2in, <10 at 3.5in+ (Class III)"; closed-cell racking "up to 300%" -> removed (no source); closed-cell 2x4 3.5in "R-21 to R-24.5" -> "about R-22 to R-26 (ICC-ES)"; polyiso cold-temp "R-3.5-4.5 below 25F (BSC)" -> "NRCA: R-5.56/in at 75F, R-4.91 at 40F, R-4.05 at 25F"; Comfortbatt "~R-4.2/in (Rockwool)" -> "R-4.0-4.3/in from ComfortBatt data sheet"; blown fiberglass "R-2.2-2.7/in, lowest" -> "R-2.5-3.0/in at 75F"; blown fiberglass "18-20in = R-44 to R-49" -> "16.4-18.25in = R-49"; cellulose "settles ~20%, install 20% deeper" -> "~10% settling, charts build it in, install ~11% above settled"; fiberglass Grade III "30%+ (RESNET)" -> "ORNL 14% drop; JM/Navy 34% from 4.2% void"; R-21 wall "closer to R-17" -> "R-17.0 clear-wall (studs included), whole-wall lower"; savings "15-25% per DOE" -> "avg ~15% H&C (7-20% by zone), ENERGY STAR"; XPS "R-4.5-5.0/in" -> "R-5.0/in (ASTM C578)"; XPS "settles to R-4.5" -> "legacy HCFC ~R-4.5-4.65; NGX LTTR R-5.0"; R-19 batt "6.25in (2x6)" -> "about R-18 compressed into a 5.5in 2x6"; mineral wool ">2,150F" -> removed, "noncombustible (ASTM E136)"; fiberglass melt "1,300-1,500F" -> removed; blue XPS "Dow" -> "DuPont, formerly Dow"; wall code "R-20+5ci (zone 5+)" -> "2021/2024 IECC CZ4-8: R-30 or R-20+5ci or R-13+10ci or R-0+20ci"; radiant "zones 1-3" -> "CZ 1-2, with attic ducts"; removed NRC/FSI table numbers, "~60%" market share, "80%+" recycled content, "100x" expansion, "2-3in holes", "Class A (foil)", "2025-2026 national averages", dead BSC/ORNL/Rockwool/DOE/ENERGY STAR links

Corrected home-page material R-per-inch ranges, 2021 IECC prescriptive wall/basement/crawl options and climate-zone HDD bands, replaced the misattributed DOE savings/installation-loss figures with sourced ENERGY STAR/ORNL values, and added inline citations with a Sources list.

Mineral wool R-3.0–R-3.3 -> R-3.7–R-4.3; blown fiberglass R-2.2–R-2.7 -> R-2.5–R-3.0; fiberglass batts R-2.9–R-3.8 -> R-2.9–R-4.3; R-49 blown fiberglass depth 19.5 in -> 16.5–18 in (FAQ "about 19 in" -> "16.5–18 in"); R-49 fiberglass-batt depth 15.5 in -> 15.75 in (R-30 + R-19 stacked); Zone 4 (except Marine) wall R-20 or R-13+5ci -> R-30 or R-20+5ci or R-13+10ci or R-0+20ci; Zone 3 wall added or R-0+15ci; Zones 1–2 wall R-13 -> R-13 or R-0+10ci; Zones 4 Marine/5/6/7/8 wall R-20+5ci or R-13+10ci -> R-30 or R-20+5ci or R-13+10ci or R-0+20ci; Zone 4 Marine basement/crawl R-10ci or R-13 -> R-15ci or R-19 or R-13+5ci; Zones 5–8 basement/crawl R-15ci or R-19 -> R-15ci or R-19 or R-13+5ci; Zone 5 HDD 4,500–5,400 -> 5,400–7,200 HDD65, Zone 6 5,400–7,200 -> 7,200–9,000, Zone 7 7,200–9,000 -> 9,000–12,600, Zone 8 9,000+ -> above 12,600; Zone 7 example "Duluth, northern New England" -> "Northern Maine (Aroostook County), interior-south Alaska"; Dallas moved from Zone 3 to Zone 2; FAQ savings "DOE estimates ... 10-50%" -> "ENERGY STAR ~15% (7-20% by zone)"; install-loss "reduce effective R-value by 30% or more (incl. missing vapor barriers)" -> measured ORNL ~14% worst-typical plus gap/void one-third-or-more (vapor-barrier claim dropped); vapor-retarder "Zones 4-8 interior" -> "Zones 5-8 and Marine 4 interior Class I/II; Zone 4 except Marine Class III"; removed "last verified May 2026" and added a 2024-IECC-edition note.

Corrected and sourced building-science definitions across the glossary, wiring inline citations and a source list, fixing RESNET grading, cellulose settling, vapor-retarder class boundaries, marine-zone code, Class A fire ratings, and framing-loss figures.

blowing-agent HFC GWP "700-1,400" -> "high GWP (e.g. HFC-134a ≈1,430)"; RESNET Grade split ">2% of insulated area" + "30%+ lower than Grade I" -> ANSI/RESNET/ICC 301-2014 Add F-2018 App A (Grade I ≤2%/no gap >¾in, Grade II ≤15%) with measured ORNL −14%, JM-Navy −34%, BRANZ −35%; cellulose settling "~20%" -> "~10%" (stabilized 0.7-5.3%) and over-blow "~20%" -> "~11%"; blown fiberglass settling "1-3%" -> "about 1% or less"; Class A FSI "≤25 and SDI ≤50" -> "FSI 0-25 and SDI 0-450" (SDI ≤50 relabelled as ASTM C665 product limit); marine "share R-value with primary zone (3 or 4)" -> "3C tracks zone 3, but Marine 4 (4C) follows zone 5"; vapor classes "<0.1 / 0.1-1.0 / 1-10 perms" -> "0.1 perm or less / >0.1 to ≤1.0 / >1.0 to ≤10 perm (IRC R702.7)" (both perm-rating and vapor-barrier entries); thermal-bridging framing "3-4×" -> "about 2.5-3.5×" and R-23 wall "about R-18 whole-wall" -> "about R-18 clear-wall (studs included)"; ASTM C177 "predecessor" -> "alternative guarded-hot-plate method"; r-value additive sum relabelled "~R-19 wall assembly" -> "≈R-19.9 center-of-cavity (before framing)"; removed unsourced "1.5-3.0 ACH50" target, "40-60% of heat loss" stack-effect figure, "most US jurisdictions" quantifier, spray-foam "FSI ≤75, SDI ≤450", and the "do not substitute" Type X compliance claim

Replaced a fictional byline and the "homeowner-built" About persona with the real operator and author, and removed invented first-person field experience.

A fictional default byline and the North Dakota homeowner origin story were removed; the site now names its operator (Moving Data Systems d.o.o.) and author (Marko Visic, BSc Physics). First-person field-experience claims such as "we have inspected / installed / measured" were removed from 22 article pages. About, Contact, Editorial Policy, Privacy Policy, Terms of Use, Disclaimer and Data Sources were rewritten to match how the site is run: one author, no ads or affiliate links live, and every figure sourced to a primary document.