LAFAYETTE · COST

Typical cost and payback in Lafayette

A 7 kW south-facing system at the Lafayette coordinates (80026) produces about 10,600 kWh/year per NREL’s PVWatts v8 model. At current Xcel Energy rates and a 50/50 self-consume to export split, that production carries an offset value near ~$1,830/year. The net out-of-pocket and payback figures above use those inputs; the methodology and source links are documented in the worth-it diagnostic.

How big a system fits a Lafayette home?

A 7 kW system is the median residential size in Boulder County and the baseline NREL’s PVWatts model uses. At the 80026 coordinates, a south-facing array at 20° tilt produces 10,600 kWh/year. The Boulder County average residential bill is $101/mo, which a 7 kW array offsets a meaningful share of for a south-facing roof. East or west orientation drops annual production by 10 to 20%; predominantly north-facing roofs rarely pencil. Households with above-average usage ($150+ monthly bills, EV in the driveway, heat pump on the way) often size up to 8 to 10 kW; under-$80-monthly households are usually below the sizing floor where payback works.

Gross install cost

Residential turnkey installs in Colorado currently price at roughly $2.80 to $3.40 per watt for a typical 6 to 8 kW system, consistent with NREL’s residential PV benchmark and the Lawrence Berkeley National Laboratory Tracking the Sun annual installed-price reporting. At 7 kW, that translates to a gross install range of roughly $18,900 to $21,000 before any incentives. “All-in” price ranges typically include the panels, inverter, racking, permitting, and labor, but should be verified against the specific proposal. Quotes outside this band, particularly above it without a clear reason (battery storage, complex roof, major service panel upgrade) warrant a second opinion.

After incentives

The federal Section 25D Residential Clean Energy Credit expired December 31, 2025 under Public Law 119-21, so 2026 cash and loan installs do not receive a 30% federal credit. Summit’s page on the federal credit in 2026 explains the change and what Section 48E still covers for third-party-owned systems.

Solar*Rewards compensates residential systems for their renewable-energy credits, with payment terms set by Xcel Energy (under Colorado PUC Renewable Energy Standard). The exact REC value varies with the active program block or contract terms; current values are published by the Solar*Rewards program . Solar*Rewards production incentive (Xcel) / no statewide upfront residential rebate also applies for qualifying residential systems: Approximately 2¢/kWh on all generated kWh under a 20-year Xcel Solar*Rewards contract. Property tax exemption applies to system value.. The rebate amount and eligibility rules move with each CO PUC tariff cycle or program year.

For the Lafayette reference system in 2026, the net cash out-of-pocket is ~$18,900 to $21,000, the same as the gross install. Solar*Rewards pays out as production happens over the 20-year contract rather than as an upfront subtraction, and Section 25D federal credit expired December 31, 2025. The 11 to 12 years cash-payback number captures the full annual offset (bill savings plus production payments) against that gross install. The full math is documented on the worth-it page.

Payback range

Cash payback at current Xcel Energy rates and the reference system specs lands at 11 to 12 years. Financed payback runs longer, at 15 to 18 years, once dealer fees (typically 10 to 30% per the CFPB August 2024 issue spotlight) and interest layer in. The difference between the two is mostly the dealer fee, not the interest. Asking for the cash $/W alongside any financed proposal is the single most effective tool a homeowner has at the quote stage; the gap is the markup.

Assumptions and limits

• Production estimates trace to NREL’s PVWatts v8 model at the Lafayette ZIP. Real installs vary with the actual roof plane, shade pattern, and equipment.
• Utility rate basis is Xcel Energy’s current residential tariff filed with the Colorado Public Utilities Commission. Supply and delivery rates reset on the utility's filing schedule, so the figures here should be re-verified against the current CO PUC filings before treating any number as fixed.
• This page does not model battery storage, electric vehicle load offset, or future rate-case-driven changes to the supply rate. Each of those moves the payback figure, sometimes substantially. A real proposal should call them out explicitly.