ECN Forum Forums General Topics of the Trade Alternative Energy PV panels

Solar efficiencies have now reached performance levels beyond imaginations forty years ago.

20% and beyond is now becoming common. The nicer aspect is that a smaller foot print makes installation even more practical.

There is still a range in performance per panel: 175 to 215 W/Panel... with the panels being similar in size.

Never mentioned but relevant: the array shades the roof. For us in the southern climes, that's not a trivial thing. Air conditioning loads are the peak driver of juice demand -- and shading the roof helps a lot.

The bigger concern for any installation is maintaining the integrity of the roof. In the rush to install I can imagine a lot of flakey operators taking short cuts on the roof seal.

I'd have long ago installed solar. But I can't find any mounting able to overcome Spanish tile -- the classic stuff. It's brittle and drills poorly.

Yes, the roof could be an issue. I'm not aware of any resi or comm leak issues, and tile roofs are few and far between over here.

Spoke to a PM today as to an upcoming comm job (4.26MW) scheduling. The roof rip-off should start tommorrow, & be about 3-4 weeks depending on weather.

BTW, one ground mount job has 225 watt panels.

The 'shading' thought never crossed my mind! I'll have to get one of the PM's to get some temp readings, perhaps an additional 'sales tool'??

I just thought of another question. If you want to re-roof your house, would all of the PV panels have to come off in order to re-roof the house?

Yes the solar panels do need to come off if you re-roof. That is actually the best way to get some used ones cheap, particularly if the roofer blames the leak on the collectors. That is where I got my pool collectors (8 for $150)

Greg,

You are always thinking! Keep it up my friend! On a more serious note, that would mean that the price of a new roof might double? I don't know how much a new roof goes for. ( Thank God) My roof is brutal with 12 on 12 pitch pretty high up off of the ground.

I assume the way you have to do this if you are keeping the solars is to call the solar contractor, have him dismantle his system, get the roofer to do his thing, then have the solar guy reinstall the system.

That will push your payback time down the road a few years.

When I put in my addition I was thinking about solar collectors so I put Grace Ice and Water membrane over the whole south side to make it a little more tolerant of penetrations. I still haven't decided to do the solar thing yet.

My bet is the shingle warranty is void if you put collectors up and your solar warranty is void if the certified solar installer does not do the remove/replace on a re-roof.