Idaho
Not "experts say." The adopted code rule, the city's own signed policy, the utility's published table — read, quoted, and dated. And where a city hasn't published an answer, that's what it says.
Get your three numbers ↓Costs, code numbers, brands, and permits
4 Idaho guides · 41 national → Doors National guides — they apply in IdahoEntry, patio, and storm doors
2 guides → Siding National guides — they apply in IdahoVinyl and fiber cement — durability and cost
3 guides → Sunrooms National guides — they apply in IdahoThree-season vs four-season, honestly
2 guides →Windows Start here
Your code number follows your climate zone. Your rebate follows your utility. Your permit follows your city hall. They don't share a boundary — so pick your town and take all three.
The number your windows must hit
0.32 / 0.30
U-factor max — Zone 5 / Zone 6. Idaho amended Zone 5 looser than the national 0.30.
The energy-code guide → 02What your utility pays back
Four answers
four utilities, one of which pays nothing
Which lane you're in is decided by one line on your power bill, not by your city.
Costs & rebates → 03Whether you need a permit
Your city decides
There's no statewide rule. Fourteen jurisdictions checked; eight don't publish an answer.
The permit map →Every figure here traces to a primary source — the adopted code rule, a city's own policy PDF, a utility's published table. Where a city hasn't published an answer, we say so.
Want all fourteen side by side? The permit map, city by city →
City not in the list? The code numbers above hold statewide — your climate zone comes from the county table in the energy-code guide, and your utility is the name on your power bill. For the permit answer, one call to your city's building desk settles it; ask for it in writing.
Written for this state specifically — Idaho's rule, Idaho's utilities, Idaho's dealers.
Idaho's amended code sets a fenestration U-factor of 0.32 in Climate Zone 5 and 0.30 in Zone 6 — and no SHGC limit at all. What that means for your quote, and why the code minimum is a low bar here.
Read the guide →
Idaho has no statewide permit rule for window replacement. Boise, Ada County, Post Falls and Twin Falls require one; Nampa doesn't. Here's the verified city-by-city map — and what to do in the eight cities that don't publish an answer.
Read →
National reviews rank brands you may not be able to buy. Here's what's actually sold in Idaho — Milgard's dealer bench, the Earthwise plant in Nampa, and why Boise and Coeur d'Alene get two different answers.
Read →
There is no authoritative price index for replacement windows in Idaho. Here's the real spread across every source that covers the state, how to read a quote line by line, and the one rebate table that's actually confirmed.
Read →Most window content is written once, nationally, then sprinkled with a state name. That breaks in Idaho faster than almost anywhere: the state amended its Zone 5 code number looser than the national baseline, four utilities run four different rebate programs, and permit rules flip across a line you can't see from the curb.
So every figure on these pages was pulled from the source that governs it, and dated. When a city publishes nothing, I say it publishes nothing — that's more useful than a confident guess, and it's the difference between a guide and content.
Marc Hanley
Measures, quotes, and sells replacement windows in North Carolina homes. Writes down what the quote sheet doesn't say.
Idaho pages last updated August 4, 2026 — the date the newest guide's sources were read, not a badge.
