Nevada Climate Zones by County
Nevada's 17 counties span climate zones 3B to 5B under the 2021 International Energy Conservation Code (IECC). Zone 5B is the most common, with 9 of the 17. For reference, Las Vegas is in zone 3B and Reno and Elko are in 5B.
Insulation minimums for each zone in Nevada
| Zone | Counties | Attic | Wood-frame walls | Floors over unheated space | Basement walls |
|---|---|---|---|---|---|
| 3B | 1 | R-49 | R-20, or 13+5ci, or R-15ci | R-19 | R-5ci or R-13 |
| 4B | 7 | R-60 | R-30, or 20+5ci, or 13+10ci, or R-20ci | R-19 | R-10ci or R-13 |
| 5B | 9 | R-60 | R-30, or 20+5ci, or 13+10ci, or R-20ci | R-30 | R-15ci, or R-19, or 13+5ci |
Minimums from the 2021 IECC (Table R402.1.3). Many areas still enforce an older edition, so check with your local building department. See sources.
Which energy code Nevada uses
Nevada enforces the 2024 IECC with amendments for homes (in effect since Aug 2024), though local governments have a say in how it is adopted and enforced. Source: US Department of Energy, September 2026. Local governments can adopt newer codes or amendments. See every state's energy code.
What changed from the 2018 map
Seven counties moved one zone warmer in the 2021 map: Carson City (independent city) (5 → 4), Douglas County (5 → 4), Esmeralda County (5 → 4), Lincoln County (5 → 4), Lyon County (5 → 4), Mineral County (5 → 4), Nye County (5 → 4). If your town still enforces the 2018 or 2015 code, the older zone applies to permits.
Every county in Nevada
| Name | Zone (2021) | Zone (2018) | Details |
|---|---|---|---|
| Carson City (independent city) | 4B | 5B changed | Insulation → |
| Churchill County | 5B | 5B | Insulation → |
| Clark County | 3B | 3B | Insulation → |
| Douglas County | 4B | 5B changed | Insulation → |
| Elko County | 5B | 5B | Insulation → |
| Esmeralda County | 4B | 5B changed | Insulation → |
| Eureka County | 5B | 5B | Insulation → |
| Humboldt County | 5B | 5B | Insulation → |
| Lander County | 5B | 5B | Insulation → |
| Lincoln County | 4B | 5B changed | Insulation → |
| Lyon County | 4B | 5B changed | Insulation → |
| Mineral County | 4B | 5B changed | Insulation → |
| Nye County | 4B | 5B changed | Insulation → |
| Pershing County | 5B | 5B | Insulation → |
| Storey County | 5B | 5B | Insulation → |
| Washoe County | 5B | 5B | Insulation → |
| White Pine County | 5B | 5B | Insulation → |
Source: Pacific Northwest National Laboratory, Guide to Determining Climate Zone by County: Building America and IECC 2021 Updates (2022).
Frequently asked questions
What climate zone is Nevada?
Nevada spans IECC climate zones 3B to 5B; zone 5B is the most common. Find your county in the table above, or search by ZIP code.
How much attic insulation do I need in Nevada?
In Nevada, the 2021 IECC calls for R-49 and R-60 in the attic, depending on the zone. The table near the top of this page lists each zone's minimums.
What energy code does Nevada use?
Nevada enforces the 2024 IECC with amendments for homes (in effect since Aug 2024), though local governments have a say in how it is adopted and enforced. Source: US Department of Energy, September 2026. Local governments can adopt newer codes or amendments.
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