PV shingles or rack-mounted panels when the roof is due for replacement?

I’m comparing two roof designs for a house with an older asphalt-shingle roof: photovoltaic shingles installed as part of a full reroof, or conventional rack-mounted PV panels installed over a new roof covering. The roof has a moderate pitch, and the main south-facing plane appears to have enough usable, mostly unshaded area for the planned array. The final layout still needs to account for vents, setbacks, and roof penetrations.

The integrated option looks cleaner and could avoid some visible racking, but I’m concerned about serviceability. If one PV shingle fails, is it practical to replace that section without disturbing adjacent shingles? I’m also wondering how repairs work when the roofing warranty and solar warranty come from different parties, compared with a standard roof plus rack-mounted panels.

The rack-mounted system seems more flexible for future inverter or panel changes and may be easier to troubleshoot, but it adds penetrations, flashing details, and another layer of work over the roof. It also raises the question of timing: if the roof is otherwise serviceable, would installing panels now create a problem when the covering eventually needs replacement? Conversely, if a full reroof is already planned, does that make PV shingles more sensible despite their potentially lower layout flexibility and different energy yield?

For those who’ve designed or inspected both, I’d be interested in how you compare:

- Expected durability and repair access for PV shingles versus conventional panels and rails
- Energy output when the usable roof area, pitch, and shading are the same
- Warranty coordination between the roofing contractor, PV manufacturer, and installer
- Total scope when the project is a full reroof versus solar added to a sound existing roof
- Whether the cleaner appearance justifies reduced component flexibility over the roof’s service life

The roof covering type and age seem especially important here. Would you make a different choice for a relatively new architectural asphalt roof than for an older roof already scheduled for replacement?