[beembeem]

First off, I know this article is more targeted at utility-scale installations, but much of the comment section is discussing or interested in residential so it's worth bringing this piece up.

One of the problems for residential roof-mounted systems is the wind load that large flat panels introduce. This load needs to be offset with very strong roof penetrations. You need to drive large bolts directly into the trusses of the roof which requires a bit of expertise, and has risks if you knick the edge of a piece of structural timber.

Contrast this with the round tubes used by solar thermal that don't introduce large wind loads, and nearly any DIYer can drill holes in their roof to support them.

[tfourb]

This is news to my solar installation, which is not fixed to my roof structure at all. My roof is not that steep, so the panels are simply put of frames which are weighed down with concrete pavers. And this is not DIY job, but professionally installed with warranty and everything.

Similarly, most solar installations on steeper roofs here in Germany are either made without penetrations at all (by hooking special frames into the roof structure under the roof tiles), or they use very basic screws that tie into the existing roof structure. Our neighbor did his solar installation himself on a pretty steep roof, something you would absolutely not do if there were any risk of structural damage.