The permit that can issue the same day
Denver began using SolarAPP+ in April 2023 for residential rooftop solar. The software runs the compliance checks a plan reviewer would otherwise run by hand and issues the building permit through the city e-permits system, which is why the step that takes weeks in much of Colorado can take minutes here.
Eligibility is narrower than people assume. The route is built for rooftop systems on single-family or duplex homes, with an electrical service of 200 amps or less and a nameplate rating at or below 10 kW DC, and the application has to be submitted by a licensed electrician.
Those thresholds matter to your quote rather than being trivia. A design that creeps above 10 kW DC, or a home that needs a service upgrade past 200 amps, leaves the automated route and rejoins the ordinary plan review queue.
So ask the question directly: does this specific design qualify for SolarAPP+, and if it does not, what is it that disqualifies it. Sometimes the answer is a genuine constraint of your roof and your usage. Sometimes it is a slightly larger system than you need, and the trade is worth seeing before you agree to it.
A permit is not permission to operate
A building permit is the city allowing the work. Permission to operate is your utility allowing the finished system to export to the grid and be credited. They are separate approvals from separate organisations, and instant permitting accelerates only the first one.
This is the gap that surprises Denver homeowners. Panels can be on the roof, the inspection can be signed off, and the system can still be sitting idle or producing without being credited because the interconnection side has not completed.
Ask your installer for two dates rather than one: the expected installation date and the expected date of permission to operate. An installer who quotes only the first is describing the part of the project they control, which is not the part that starts saving you money.
Ask also what happens in between. Some systems can run and self-consume while awaiting final utility approval and some must stay off, and the answer depends on your equipment and your utility rather than on a general rule.
The election most Denver homeowners never realise they made
Denver is Xcel Energy territory, and Xcel's net metering arrangement rolls excess generation month to month and year to year into what is called a Solar Bank. The part that gets skipped is that you elect how that bank is treated, and the election has real money in it.
Option A is continuous rollover. The credits never expire and can be used whenever your consumption exceeds your generation, but the Solar Bank cannot be cashed out, and no credit is given if you move or stop service.
Option B is a year-end payout. Xcel cashes out the Solar Bank at the end of the year and sends a cheque for the excess energy, purchased at the average hourly incremental cost of electricity from the previous 12 months, which is well below the retail rate.
Waiving the decision defaults you to the year-end payout. If you expect to sell the house inside the payback period that default may be the right outcome rather than the wrong one, but it should be a decision you made rather than one that happened to you. Ask your installer which election your paperwork specifies.
The parts that survive without qualification
The 30 percent federal Residential Clean Energy Credit under Section 25D expired for property placed in service after December 31, 2025. A cash or loan purchase in Denver now receives no federal tax credit, and a quote that still applies one is overstating your return by roughly a third.
Section 48E, the commercial credit, does survive at 30 percent and is available to third-party owners under leases and power purchase agreements. The provider claims it. Ask what they claim and what portion actually reaches you in the rate offered, and confirm the treatment with a tax advisor rather than with the salesperson.
What remains without qualification is full retail net metering, the property tax exemption for residential systems of no more than 100 kW AC under Section 39-3-102 C.R.S., the residential energy sales and use tax exemption, and the electricity you stop buying.
Ask any installer to rebuild the savings projection from those four things alone. Treat reluctance to produce that version as informative in itself.