The problem with rooftop solar in the US is that the install cost is so high. Even if the panels were free, there are many areas where you'd be looking at 15+ year payback, which is a bad investment.

I'd love to do solar, but the only way I can make the numbers work is if I DIY'd the full install.

What makes the install cost high? Where I live in Australia, 44% of houses have rooftop solar and installations seem to be done in a fraction of a day. Seems like a pretty efficient process where they bolt racks to the roofing iron and then attach panels to the racks, wire it up, etc.

Here's a decent breakdown for US installs: https://solaractionalliance.org/residential-solar-panel-cost...

Your 5-10k range installs will be $10-20,000 AFTER the tax credit, which might be a little higher now than when that graphic was put together.

Of course, this doesn't account for things like needing to re-do existing electrical work to get affected areas up to code, or if you need to replace the shingles on your roof while you're at it because it's typically recommended to do both at the same time if you're going to add solar.

Then again, you may also have the problem of ensuring your roof will withstand the extra weight, depending on the system. Most people are probably fine here, but for older houses in snowy climates it's worth thinking about as well.

I've looked into solar for my house. Aside from not getting enough sun throughout the day due to tree shade, there's also the problem that every solar calculator available wants to pretend that energy prices are going to go up 5% a year. Well, I've lived at my current house for 5 years and they haven't gone up once. The real payback for me is 20 years, if I'm lucky, even without the trees in the way.

Wow. That's quite remarkable. 7kW here was under US$4,000 including inverter, panels, installation and accounting for government rebates (some sort of credit system that the energy company handles by buying your credits off you, AFAIK). That was installed onto typical industrial metal roofing sheets - not sure of the name of it. Similar price at home installed onto corrugated iron which is very common in Australia.

>What makes the install cost high?

US skilled labor costs are insane. It makes all construction costs ridiculously high.

Assuming you want net metering, you’d need controls in place for grid safety and such and all the permits and inspections which take time and cost money.

I imagine all that is pretty standard here also - South Australia isn't exactly without regulation or seemingly high labour costs. I used the same company at the office building and then at home, and each was painless. Approve an easy quote and then everything is later installed on a particular day. Both were in the 5-10kW range.

At the office building, the estimated payback was all of two years.

It’s not. You may have to retrofit parts of your electrical system.

People also stuff like leasing that adds overhead.

Micro inverters don't solve everything. Installing panels where they'll be in full sun for an hour a day isn't a good use of resources.

Wouldn't a much simpler and cheaper approach be bypass switches for each panel instead of microinverters?

For that matter, can solar panels be wired in parallel instead of in series?

They can, but you need a suitable equipment- thicker wires, at a minimum. Wiring in parallel means the voltage is the same regardless of the number of panels, but the current sums up- so your inverter and/ or controller will need to be rated appropriately.