Sun hours are not output
Ask what temperature assumptions sit behind your production estimate and whether the model was run for your specific location and roof rather than derived from a regional average. That question separates an installer doing engineering from one filling in a template.
Ask to see monthly figures rather than an annual total. The annual number hides the shape, and the shape is what tells you whether the system meets expectations in July rather than on average across the year.
Ask how the array is mounted and how that affects operating temperature. Airflow beneath the modules matters in this climate, particularly on a low-slope or tightly flush installation where heat has less opportunity to escape.
Ask for a shading assessment covering the whole year rather than the hour of the site visit. Shading costs more than people expect because it removes production in the middle of the day, when the array is otherwise strongest.
What that production is actually worth
A large annual production figure is not the same as a large return. New customers enroll in Tier 4, which credits excess energy at 75 percent of the retail rate, while electricity consumed as it is generated avoids a purchase at the full rate.
So what matters is the split: how much of the production your household uses directly, and how much leaves the house at three quarters value. Ask your installer to model that split explicitly rather than quoting an annual offset percentage.
Excess energy earns credits which are recorded on your bill and automatically applied in the next billing period in which you consume more than you produce, so they carry forward and get used rather than expiring. They still were earned at 75 percent.
Ask whether the projection uses 75 percent for exports at all. A model built on one-to-one crediting, or carried over from an earlier tier, will overstate what you actually receive.
The roof it sits on
Panels outlast most roof coverings, and intense sun with extreme summer heat ages roofing faster than a year count suggests. Ask for a condition assessment rather than an age estimate.
If the covering is within a few years of the end of its life, replace it before the array goes on. Removing and reinstalling a system to reach the roof underneath is a cost with no offsetting benefit at all.
Ask how mounting penetrations are flashed and sealed, what method the roofing manufacturer approves for your covering type, and what the workmanship warranty covers on them and for how long. Leaks around mounting hardware are the most common physical failure in residential solar.
Establish who honours each warranty. Panels, inverter and workmanship are commonly covered by three different parties on three different terms, and a company that has left the market cannot support a workmanship warranty however well written.
The tier you join, your association, and the federal credit
New Nevada customers must enroll in Tier 4, which credits excess energy at 75 percent of the retail rate, and keep that tier for a period of 20 years at the location where the system was originally installed. Earlier tiers credited 95, 88 and 81 percent and closed in August 2018, June 2019 and June 2020.
Because exports are credited at 75 percent while electricity you consume as it is generated avoids a purchase at the full retail rate, ask your installer to model the self-consumed share explicitly and value the remainder at 75 percent rather than at retail.
On associations, NRS 111.239 makes void and unenforceable any covenant that prohibits or unreasonably restricts an owner from using a system for obtaining solar energy, and treats a restriction reducing the effectiveness of the system by more than 10 percent as unreasonable. If a committee proposes moving your array, have your installer model both placements and put the difference in writing.
There is also a route that does not require litigation: under NRS 701.180(6) the Director of the Governor's Office of Energy shall make a determination within 30 days if asked to decide whether an unreasonable restriction has been placed on a solar energy system. Separately, the 30 percent Residential Clean Energy Credit under Section 25D expired for property placed in service after December 31, 2025.