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Alaska REScheck Requirements (2026)

Key facts:

  • No Single Statewide REScheck Standard

  • Climate Zones 6-9

  • 4 ACH50 Blower Door (AHFC Standard)

  • Anchorage: 2024 IECC | Fairbanks: 2018 IECC

 

Alaska is genuinely different from most other states on this point: its statewide financing-linked energy standard — the AHFC Building Energy Efficiency Standard (BEES) — explicitly does not accept REScheck or COMcheck. Compliance is verified through AkWarm software and an AHFC-approved Energy Rater instead. Separately, Anchorage and Fairbanks have each adopted their own amended IECC editions as municipal building code, independent of AHFC financing rules — Anchorage recently updated to the 2024 IECC, Fairbanks is on the 2018 IECC. Whether REScheck is accepted for those municipal permit paths isn't stated in either ordinance, so confirm directly with the local building department before assuming it will be accepted.

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Alaska has no single mandatory statewide energy code that applies to every residential permit. The Alaska Housing Finance Corporation (AHFC) administers the Building Energy Efficiency Standard (BEES), based on the 2018 IECC with Alaska-specific amendments, but BEES only applies when AHFC or other state financial assistance is used to purchase or finance a home — it isn't a universal building-permit requirement. Separately, the state has adopted the IECC as part of its general building code (administered by the Department of Public Safety / State Fire Marshal), and municipalities that are "deferred jurisdictions" — including Anchorage and Fairbanks — administer and, in Anchorage's case, further amend their own adopted edition.

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Alaska's Two-Track Energy Code Structure

⚠ This is worth reading carefully before assuming REScheck applies. AHFC's Building Energy Efficiency Standard (BEES) — the standard most commonly referenced statewide — explicitly does not accept REScheck or COMcheck for compliance. BCAP's own summary of the program states plainly that "REScheck and COMcheck are not applicable" for BEES; compliance is documented instead through AkWarm energy modeling software and certification by an AHFC-approved Energy Rater using forms PUR-101 and PUR-102.

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  • AHFC BEES:  State/AHFC financing is used to purchase or finance the home   —   2018 IECC + Alaska amendments, in effect since 2021   —   AkWarm software + AHFC-approved Energy Rater (PUR-101/PUR-102) — REScheck/COMcheck not applicable

  • Anchorage Municipal Code:  New residential construction inside the Municipality of Anchorage   —   2024 IECC (Ordinance 2026-33)   —   Not specified in the ordinance — confirm with Anchorage OCPD

  • Fairbanks Municipal Code:  New residential construction inside Fairbanks city limits   —   2018 IECC with local amendments (Ordinance 6159)   —   Not specified in the ordinance — confirm with the local building department

  • State-Administered (non-deferred areas):  Areas without their own deferred-jurisdiction status   —   State-adopted IECC via DPS/State Fire Marshal   —   Confirm with DPS/State Fire Marshal

 

Alaska Climate Zones

Alaska's climate zones are assigned by heating degree days (HDD) rather than the simpler geographic bands used in most Lower 48 states, and span four zones — 6 through 9, the coldest range in the country.

Zone  ·  Heating Degree Days  ·  Representative Areas

  • 6:  7,200 – 9,000 HDD   —   Southeast coastal — Juneau, Ketchikan, Sitka

  • 7:  9,000 – 12,600 HDD   —   Southcentral — Anchorage, Kenai Peninsula

  • 8:  12,600 – 16,800 HDD   —   Interior and Western — Fairbanks, Bethel

  • 9:  16,800 – 21,000 HDD   —   Arctic Slope — North Slope, Denali, Nome

 

Anchorage's own 2026 code-update ordinance notes an unusual local quirk: although Anchorage is officially Zone 7, its adopted thermal envelope table values have historically been reduced to roughly Zone 4 (Seattle) levels. The city describes the 2024 IECC update as a presentation change to how that's documented rather than a substantive tightening — but it's exactly the kind of local wrinkle worth confirming on a specific project rather than assuming the textbook Zone 7 numbers apply directly in Anchorage.

 

Prescriptive Requirements (AHFC BEES / 2018 IECC Alaska Amendments)

Component  ·  Zones 6-7  ·  Zone 8  ·  Zone 9

  • Wood Frame Walls:  R-25 (U-0.048)   —   R-30 (U-0.042)   —   R-35 (U-0.036)

  • Ceilings:  R-54, or R-43 with energy heel truss   —   R-59, or R-48 with energy heel truss   —   R-65, or R-52 with energy heel truss

  • Basement/Crawl Space Walls:  R-19, or R-15 continuous   —   R-19, or R-15 continuous   —   Not required

  • Fenestration (Windows):  U-0.30 max   —   U-0.22 max   —   U-0.20 max

 

These are AHFC's BEES prescriptive numbers, which apply on the state-financing track. Anchorage's and Fairbanks's municipal codes carry their own adopted tables under their respective IECC editions — don't assume the BEES numbers transfer directly to a municipal permit without checking.

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Air Leakage and Blower Door Testing

Alaska's BEES amendment sets air leakage at 4 ACH50 across all climate zones — actually a looser standard than the base IECC's zone-based requirement used in most other states (which tightens to 3 ACH50 for zones 3 and up). Testing follows ICC 380, ASTM E779, or ASTM E1827 at 50 Pascals (0.2 inch water gauge), performed at rough-in and again post-construction, or at 3 ACH50 if the air handler isn't yet installed at the time of the first test.

 

Is REScheck Accepted in Alaska?

Not for AHFC's Building Energy Efficiency Standard — the program that applies whenever state or AHFC financing is involved. BCAP's summary of the program is direct: "REScheck and COMcheck are not applicable." Compliance there runs through AkWarm software and certification by an AHFC-approved Energy Rater instead.

For a project permitted directly through Anchorage or Fairbanks under their own municipal IECC adoptions — rather than through AHFC financing — neither city's ordinance specifies whether REScheck is accepted as compliance documentation. The DOE's own national tracking page for Alaska leaves that field blank rather than confirming it either way. If a project isn't going through AHFC financing, the safest path is to ask the local building department directly whether REScheck, AkWarm, or another method is expected before ordering a report.

 

Common Permit Requirements

  • AHFC-financed projects: PUR-101 form completed by an AHFC-approved Energy Rater, plus AkWarm modeling output

  • Anchorage or Fairbanks municipal permits: compliance documentation as required by the local building department under the applicable IECC edition

  • Insulation R-value and window U-factor specifications matching the applicable zone table

  • Blower door test results at 4 ACH50 (AHFC standard) or the applicable local requirement

  • Manual J HVAC load calculations, as required by the permitting jurisdiction

 

Common REScheck Failure Reasons in Alaska

Most Common Errors

  • Assuming REScheck applies without checking whether the project is on the AHFC-financing track, where it explicitly doesn't

  • Using standard Lower-48 zone tables instead of Alaska's amended R-values, which run considerably higher than most other Zone 6-8 jurisdictions

  • Missing Anchorage's local envelope-table adjustment, which differs from the textbook Zone 7 numbers

  • Wrong climate zone assigned — Alaska's zone boundaries follow heating-degree-day thresholds, not the simpler geographic logic used in most states

 

Documentation Issues

  • Submitting a REScheck report for an AHFC-financed project instead of the required PUR-101/AkWarm documentation

  • Blower door results referencing the wrong ACH50 threshold for the applicable track (AHFC's 4 ACH50 vs. a municipality's own requirement)

 

Major Cities and Jurisdictions in Alaska

Anchorage

Zone 7. The Municipality of Anchorage administers its own building code, updated to the 2024 IECC under Assembly Ordinance 2026-33. Confirm current compliance documentation requirements directly with Anchorage's Office of Community Planning & Development (OCPD).

 

Fairbanks

Zone 8. Fairbanks adopted the 2018 IECC with local amendments under Ordinance 6159. As one of Alaska's coldest major population centers, its prescriptive requirements sit at the higher end of the state's range.

 

Juneau, Ketchikan, and Sitka

Zone 6 — Alaska's mildest climate zone, covering the Southeast coastal panhandle.

 

Mat-Su Borough (Wasilla, Palmer)

Zone 7, adjacent to Anchorage. Confirm which code track applies — Mat-Su Borough administers its own permitting separate from the Municipality of Anchorage.

 

Bethel and Western Alaska

Zone 8.

 

North Slope Borough and the Arctic

Zone 9 — the state's most extreme climate zone, with basement wall insulation not required under the BEES prescriptive table.

 

Frequently Asked Questions About REScheck in Alaska

Does Alaska accept REScheck?

Not for AHFC's Building Energy Efficiency Standard (BEES), the program that applies whenever state or AHFC financing is used — that program explicitly does not accept REScheck or COMcheck and instead requires AkWarm software and an AHFC-approved Energy Rater. For municipal permits in Anchorage or Fairbanks issued outside the AHFC financing track, neither city's ordinance confirms REScheck acceptance either way, so check with the local building department first.

 

Does Alaska have a statewide energy code?

Not a single universal one. AHFC's BEES applies specifically to AHFC- and state-financed homes. Separately, the state has adopted the IECC as part of its general building code, administered by the Department of Public Safety, while deferred jurisdictions like Anchorage and Fairbanks administer and amend their own adopted editions.

 

What energy code does Anchorage use?

The 2024 IECC, adopted under Assembly Ordinance 2026-33. Anchorage is officially Climate Zone 7, though its adopted envelope tables have historically used values closer to Zone 4.

 

What energy code does Fairbanks use?

The 2018 IECC with local amendments, adopted under Ordinance 6159.

 

What climate zones does Alaska have?

Four: Zone 6 (Southeast coastal, including Juneau and Ketchikan), Zone 7 (Southcentral, including Anchorage), Zone 8 (Interior and Western, including Fairbanks), and Zone 9 (the Arctic Slope).

 

What is Alaska's blower door requirement?

Under the AHFC BEES standard, 4 ACH50 across all zones, tested per ICC 380, ASTM E779, or ASTM E1827 at 50 Pascals.

 

What software is used instead of REScheck in Alaska?

AkWarm, Alaska's own energy modeling software, paired with certification from an AHFC-approved Energy Rater using forms PUR-101 and PUR-102. This applies to AHFC-financed projects; it isn't necessarily required for municipal permits outside that financing track.

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