Title 24 Reports in Nevada County

Two centres, one on each side

On the western slope, Grass Valley, Nevada City, Penn Valley, Lake Wildwood and Alta Sierra are all zone 11. Over the crest, Truckee and Floriston are zone 16. Five of the eight ZIP codes we derive for the county are zone 11 and three are zone 16.

The mountain side here is no outlying corner, and the incorporation record shows it. Each side has its own incorporated government: the California Department of Finance's 2026 estimates list Grass Valley and Nevada City, both zone 11, and the town of Truckee, in zone 16.

Truckee permits its own zone 16 work

Inside a city or town's limits that government issues the permit; on unincorporated land the county does. So the county divides four ways. A zone 16 project inside Truckee's limits goes to the town; one outside them, to the county. On the western side the same choice is between the county and Grass Valley or Nevada City. The zone is fixed by the ZIP in every case; only the permitting office changes.

Two ZIP codes counted with Placer

Two Nevada County communities have ZIP codes that Placer holds the larger part of, so we count those ZIPs on Placer's side: Lake of the Pines, south of Grass Valley, in 95602 (zone 11), and Soda Springs, near the crest, in 95728 (zone 16). Both are zones this county already contains, so the result does not change — but a project there is checked by ZIP, not by county name.

What the crest does to a report

Zone 11 is a genuine two-season climate with hot summers and cold winters, where heat pumps suit both loads and the envelope works in both directions. Zone 16 is heating-led, the coldest assignment in the state. The 2025 Energy Code, which applies to permit applications submitted on or after 1 January 2026, is the same on both sides of the pass; what it asks of a house is not, because its requirements are set zone by zone.

Every ZIP code by zone

Zones per the Energy Commission; county membership and community names per the 2020 Census.

• Climate zone 11 — 95945 (Grass Valley); 95946 (Lake Wildwood, Penn Valley); 95949 (Alta Sierra); 95959 (Nevada City, Graniteville, Washington, North San Juan); 95975 (Rough and Ready)
• Climate zone 16 — 95986 (Washington); 96111 (Floriston); also 96161, split with a neighbouring county (below)

A ZIP code that crosses the county line

• 96161 (Truckee, Kingvale) — about 70% within Nevada County, the remainder in Placer 30%

Truckee's ZIP code runs over the line into Placer County, and Kingvale, near the crest, is itself a Census place of both counties. The zone is 16 on either side; the line decides whether the town of Truckee, Nevada County or Placer County issues the permit.

Finding the zone for your own project

The zone is set by the project's location and confirmed from the ZIP code against the Energy Commission's published table — not from the county name and not from the nearest large town. Because Nevada County contains more than one zone, that check decides which set of numbers a report is written against.

Give us the project address and we determine the zone as part of preparing the report. It is the first thing established, because every insulation, glazing and equipment figure downstream depends on it.

Climate zones in Nevada County

Nevada County contains California climate zones 11 and 16. The zone drives the insulation, glazing and equipment performance a report has to demonstrate, and it is confirmed from the project ZIP code against the Energy Commission's published table.