Xcel in the suburbs, CORE on the plains
Aurora, Centennial, Englewood, Littleton, Greenwood Village, Cherry Hills Village, Glendale, Sheridan and Columbine Valley are mostly Xcel territory, with its 5–9 pm weekday on-peak window and 2.7-to-1 peak-to-off-peak price ratio. Foxfield, Deer Trail, Byers and much of the rural east are CORE members, and utility maps show CORE reaching into parts of southeast Aurora and eastern Centennial as well. Mountain View Electric serves a sliver at the county’s southeast edge.
The difference matters. CORE offers net metering only on home systems of 10 kW AC or less, sized to no more than 200% of annual use; exports from larger home systems are credited at CORE’s avoided cost, $0.04616 per kWh as of May 2026. An oversized array that would bank credits under Xcel can waste value under CORE.
Permits: city first, county only if unincorporated
Aurora, Centennial, Littleton, Englewood and Greenwood Village each run their own permit process, so the first step is confirming whether your address is inside a city. Bennett, which straddles Adams and Arapahoe, is one of the few Colorado jurisdictions using SolarAPP+ for automated solar permits.
In unincorporated Arapahoe County, the county requires every solar contractor to hold NABCEP certification and a county contractor license. Its residential PV submittal checklist calls for a Colorado-licensed structural engineer’s evaluation letter designed to 115 mph wind and a 30 psf non-reducible roof snow load, a stamped roof aerial with pathways and setbacks, and complete one-line or three-line electrical diagrams. Incomplete submittals are rejected at intake, and re-reviews carry additional fees.
Separate permits for batteries, chargers and panel work
Unincorporated Arapahoe County treats a battery, an EV charger, a main-breaker derate and a service upgrade as separate permits from the solar array itself. A battery also needs a stamped mounting detail from a Colorado engineer, and a charger or derate needs an electrical service load calculation.
That’s more paperwork than many jurisdictions require, but none of it is unusual for us. It mostly means the full project needs to be designed up front so each permit matches the others.
Hail, wind and the eastern plains
The whole county lies in the Front Range and plains hail corridor. On the open east side, wind exposure is as much a design issue as hail, and ground mounts on acreage need foundations and racking rated for it.
Snow loads are modest compared to the foothills, and south-facing arrays shed snow quickly. The larger risk on older suburban roofs is hail damage to shingles under the array — a good reason to check roof age before installing.
New construction and the 2023 electrical code
Unincorporated Arapahoe County adopted the 2023 National Electrical Code and new electric-ready, solar-ready and EV-charging provisions effective July 9, 2024, applying to new construction and some remodels. If you are building on a rural parcel, those rules affect conduit, panel space and roof layout from the start, which makes adding solar later much cheaper.
FAQ
Questions we hear
Is my Arapahoe County home on Xcel or CORE?
West-side suburbs are mostly Xcel; the rural east and parts of the southeast are CORE. Your electric bill is the reliable answer, and it changes how we size your system.
Why does Arapahoe County require NABCEP certification?
The county requires every solar contractor working in unincorporated areas to provide NABCEP certification and hold a county contractor license. Cities within the county set their own licensing rules.
Do I need a separate permit for a battery in unincorporated Arapahoe County?
Yes. The county requires a separate permit for energy storage, along with a stamped engineer’s mounting detail, even when the battery is installed with new solar.
Why would CORE members size a solar system differently?
CORE net-meters home systems of 10 kW AC or less. Above that, exports are credited at CORE’s avoided cost — about 4.6 cents per kWh as of May 2026 — so a larger system loses value on every exported kilowatt-hour.
I live in Centennial. Does the county permit my solar?
No. Centennial issues its own permits. The county’s process applies only to unincorporated addresses.
Is a ground mount practical on acreage near Byers or Deer Trail?
Often, yes. Ground mounts avoid roof-age problems and can be aimed perfectly, but on the open plains they need foundations and racking designed for high wind. We check permitting with the county before quoting.