[vinn]

Thanks for the encouragement! You're right on the Astronergy panels, but the idea is the same - use an oversized PV panel so I can eek out a bit more from it.

Originally Posted by where2

The only part of the 4.4kW array on my roof that was farmed out for hire was the structural engineering to keep the array on the roof in a 3-second gust of 170mph (required by the local building department).

I think inspections and such are the hardest hurdle for most people - here in rural Montana it's really not a factor at all. I think contractors in the rest of the country would be shocked and horrified by the near non-existence of building codes and permits needed here. For example, I've done most of my own wiring in my house as we've remodeled and brought in an electrician on the trickier bits.

Having said that, I will do it all properly just like you did. I have friends who are structural engineers, electricians and such. Northwestern Energy used to pretty much require that only a qualified installer could connect up via net metering. Now that's only a requirement if you go through their grant program.

So, in the end I'll just need an electrical permit and no building permit.

Originally Posted by where2

If you have questions, feel free to ask. I'm already working on my design for PV system #2 for a property my wife and I recently bought at 45.8°N.

So that's pretty close to our latitude.

Originally Posted by where2

I will say this: Item #3, that 270° facing roof with only a 5° tilt may be a bummer. How much snow do you get? A ground mount facing 180° with the proper tilt may justify the added expense of the ground mount.

We live in town and have a small yard. Even if we did have room somewhere in the yard, the trees across the street would shade a lot of it. By getting it up high I can avoid that. (Another reason for the microinverters - one of my own trees is just tall enough that I might get a tiny bit of shade on the one corner where I want to install it in the early morning hours.)

With regards to snow, surprisingly we don't get that much on the roof - it's dry almost all winter. We have pretty high winds (which is something I'll have to design for - the roof mounts will have to be bombproof and preferably not allow wind to get under the panels, although I do think I need some air circulation to vent excessive heat for the three months of the year it gets hot.) The wind blows most of it. It does get warm enough where we are that it typically melts off in between storms. (It's 36 degrees right now and we don't have much snow around.)

Now, the surface I want to mount this on, since it's kind of flattish, potentially I could build some kind of structure to get the 180 degree orientation. However, the tilt involved on it would catch the wind - I think making it structurally sound enough is way out of my league. The sustained winds regularly destroy things around here, so I think it needs to be mounted flush.