Why annual sizing misses the point here
Sizing to annual consumption is sound under net metering, because generation and consumption are netted across a billing period and timing washes out.
Schedule 137 Net Billing nets instantaneously. Only electricity your house is drawing at the moment of generation displaces the retail rate; everything else is exported at about 4.855 cents per kWh in summer or 4.033 in winter as of March 1, 2026.
So two households with identical annual consumption and identical systems can see very different results, depending only on when they use power. The hardware does not distinguish between them.
The design input that matters is your load shape through a day, not your annual kilowatt hour total. Ask whether the design was built from interval data, if your meter provides it, or from twelve monthly bill totals.
Where the marginal panel stops paying
A house always has some baseline load, so the first kilowatt hours a system produces are the ones most likely to be consumed directly. Those earn the full retail rate.
As the system grows, more of its midday output exceeds whatever the house is drawing, so the marginal panels produce mostly exports. Those earn the export credit.
At some point an additional panel costs full price and produces electricity worth about a third of retail. That is where a bigger system stops being a better one, and it usually arrives before the roof runs out of space.
Ask your installer to show the return on the last kilowatt of proposed capacity separately from the return on the first. That comparison is what a sizing decision actually rests on.
Raising the self-consumption share
Shifting flexible loads into daylight is free. Dishwasher, washing machine, dryer and pool pump all move easily, and each moved kilowatt hour is upgraded from the export credit to the retail rate.
Pre-cooling the house on a hot Utah afternoon is usually the largest free lever, because air conditioning is the biggest load in the house and it runs hardest when generation peaks.
Charging an electric vehicle during the day rather than overnight is the single biggest shift available to a household that has one, and it is entirely within your control.
A battery does this automatically and at scale, which under net billing is an economic argument rather than only a resilience one. Ask for the system modelled with and without storage so the incremental value is a number.
Rebuilding the estimate from current figures
The 30 percent federal Residential Clean Energy Credit under Section 25D expired for property placed in service after December 31, 2025, and the Utah residential solar tax credit reached zero for systems installed from 2024 onward, so a cash or loan purchase receives no tax credit at either level.
Section 48E survives at 30 percent for third-party owners under leases and power purchase agreements, so ask what a provider claims and what reaches you in the rate.
What exists is retail value on self-consumed generation and the seasonal export credit on everything else, with that credit reset each March for existing customers too.
Ask for the design built from your daily load shape, the return on the marginal capacity shown separately, and a smaller system modelled alongside the proposal.