Serving Idaho since 2020 · 7+ years of experience
ACCA Manual J, S & D Reports in Idaho
ACCA-compliant Manual J load calculations, Manual S equipment selection, and Manual D duct design for Idaho homes and small commercial projects.
The Treasure Valley · McCall · Coeur d'Alene & beyond
HVAC Design for Idaho Building Codes
Idaho enforces the International Residential Code (IRC) and the International Energy Conservation Code (IECC) through the Idaho Division of Building Safety, and local jurisdictions across the Treasure Valley and beyond require properly documented HVAC sizing on permit submittals. Section M1401.3 of the IRC requires that equipment be sized in accordance with ACCA Manual S, based on building loads calculated per ACCA Manual J — exactly the documentation we produce on every job.
Idaho's climate makes accurate load calculations matter. Much of the Treasure Valley sits in IECC Climate Zone 5B (cold & dry), while higher-elevation areas like McCall and parts of eastern Idaho fall into the colder Zone 6B (very cold & dry) — the “B” marks a dry climate. Cold, dry winters and hot, dry summers mean oversized equipment short-cycles and wastes money, while undersized equipment can't keep up. A correct Manual J keeps your system right-sized for real Idaho conditions.
Whether you're a builder, contractor, or homeowner submitting for a permit, we deliver a complete Manual J, S & D package your Authority Having Jurisdiction (AHJ) can accept — typically within three business days.
Idaho Climate Zones & County Design Temperatures
Much of the Treasure Valley sits in IECC Climate Zone 5B (cold & dry), with colder Zone 6B (very cold & dry) at higher elevations and across eastern Idaho — the “B” denotes a dry climate. Design temperatures below are the 1% cooling and 99% heating values for each county, per the ENERGY STAR County-Level Design Temperature Reference Guide (ASHRAE-based).
| County | Cities Served | 1% Cooling | 99% Heating |
|---|---|---|---|
| Ada | Boise, Meridian, Eagle, Star, Kuna | 95°F | 11°F |
| Canyon | Nampa, Caldwell | 93°F | 16°F |
| Kootenai | Coeur d'Alene*, Post Falls | 89°F | 10°F |
| Bonneville | Idaho Falls | 90°F | −2°F |
| Valley | McCall, Cascade, Donnelly | 83°F | −2°F |
* The City of Coeur d'Alene specifies its own design conditions: 86°F cooling / −1°F heating.
We serve projects statewide — these are just a sample of Idaho counties. We use the recognized design conditions for your specific county and elevation when we run your Manual J.
Idaho HVAC Design FAQ
Does Idaho require a Manual J for a permit?
Idaho follows the IRC, and Section M1401.3 requires HVAC equipment to be sized using ACCA Manual S based on a Manual J load calculation. Most Idaho jurisdictions ask for this documentation on residential permit submittals — we provide the complete Manual J, S & D package.
What climate zone is my Idaho project in?
Most of the Treasure Valley is IECC Climate Zone 5B. Higher-elevation and colder eastern areas fall into Zone 6B. We use the correct design conditions for your specific city and elevation.
Will my local building department accept your report?
Yes. We produce a complete, ACCA-compliant Manual J, S & D report formatted for your Authority Having Jurisdiction (AHJ). If your reviewer requests a small change, we handle minor revisions free of charge.
What do you need to get started?
Building plans, insulation and window values, equipment locations, and preferred model numbers. See the full What We Need for a Complete Report checklist.
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Have an Idaho project? Let's talk about working together and answer any questions you have. Send us a note and we'll reach out within 24 hours. Fields marked * are required.
Business hours: Mon–Fri, 8:00 AM – 5:00 PM MT.