Not sure if I should have tilt on panels heading 262 degrees or not.

[rsilvers]

An installer is coming to plan my roof, but I want to have my own information to compare to what they recommend. I want to get 60-70 panels up there. Surfaces 1 and 2 seem to be able to fit 38 panels (LG-315), but I am not sure how to handle west-facing roofs #3 and #5 regarding optional tilt.

Roof 3 is at a 40 degree angle. 5 is at a 15 degree angle. I am not sure if they should have some tilt. Tilt will induce shadows and so the panels would have to be farther apart, and so not as many. Not as many costs less, but may or may not produce as much power.

Thank you.

[sensij]

What is the difference in modeled output when you put each face into PVWatts?

[ButchDeal]

Tilting them would just add more shadows and cut down on the number you could fit there.
I would do something like this which fits 65 modules, 20.8kw. I used LG320 modules with SolarEdge SE11400 inverters.
Should produce about 21.6MWh first year.

[rsilvers]

Very impressive. Thank you.

I am surprised you fit that many without using the surfaces I marked here in red:

[ButchDeal]

Those would not be my choose for additional modules. I would install more on the east faces before those locations to avoid the shadows.
I used Aurora to make a 3D model of your home, and many of those areas have shadows from adjoining ridges, trees, chimneys etc. The two large East faces are the next locations (though ~2 modules can be placed south facing on the east side of the chimney of the back ridge).

here is 89 modules, 29.2MWh first year, and 28.5kw:

[rsilvers]

I should add that I used 28,000kWh of power last year. And that is with the AC being on 86F. Also I have a Tesla Model-3 on order that I may drive about 10000 miles a year. Also if I had excess power I would just turn on some electric space heaters to offload the oil and propane heat.

[rsilvers]

The 3D model is very impressive. I am a SolidWorks user. I once made a model of my previous house, but not this one.

There are trees on the East side that will have some shadow issues, especially in the winter. Also, that is the front of the house. It would be nice for future resale value if the East side looked more normal. I was trying to avoid the East unless it is a bunch better. If East was about 20% or more better, then maybe I can talk my wife into it (my installer said "it is always the wife.")

[J.P.M.]

It would be nice for future resale value if the East side looked more normal. I was trying to avoid the East unless it is a bunch better.

Perhaps by the time you sell, panels on a roof will look a bit more normal, whatever that may mean. Just a thought.

[rsilvers]

This house is near me - they have lots of side modules on extreme angle mounts. My wife would never allow that and not sure I would either.

[rsilvers]

View of East side - if this helps the 3D model be more accurate.

[ButchDeal]

I should add that I used 28,000kWh of power last year. And that is with the AC being on 86F. Also I have a Tesla Model-3 on order that I may drive about 10000 miles a year. Also if I had excess power I would just turn on some electric space heaters to offload the oil and propane heat.

that 28.5kw system should do well then for you.
though here is a slightly cheaper panasonic HIT 325w module solution with 28.6MWh first year, 87 modules 28.3kw STC.

[ButchDeal]

looks like I missed that dormer on the the east roof in this model...

[sensij]

ButchDeal might not be able to say it without violating terms of the forum, but I would suggest that you contact his company directly if you really want to benefit from his expertise. They did my installation... you can find the company name in my site detail at PVOutput.org, through the link in my signature. Click on the "3.120 kW" for the site detail.

[ButchDeal]

View of East side - if this helps the 3D model be more accurate.

Yeah I got the trees

added an obstruction to represent that curved dormer (just threw this together but should be pretty accurate)

[ButchDeal]

from your front view I adjusted the trees a little taller and closer. This now performs a little better with 85 panasonic 325 HIT modules for 27.6kw, and first year production ~29.5MWh

[rsilvers]

That is very impressive. I like the heat-map. I would say that the system is a little larger than I need, so I would opt to not use the three panels on the east side just to spare the house of the front view. But I like the other locations.

I am locked into LG315 panels because I picked an installer in part based on who had what panels, and those were acceptable to me. Would the shape / size of LG 315 change the layout?

The enclosed photo shows tree height relative to the house. The trees are not grown in much at the moment, but they get a lot of leaves later.

Thank you.