Thinking about solar for home...

If you are doing solar, you should redo your entire roof. The solar is going to be up there for a long time, you want to make sure you have a good solid roof to put it on. It'll cost you a lot more if in 5 or 10 years you have to reroof the house since the solar PV system has come down in it's entirety and then put back up.

I posted pics of my install here: Anyone have solar panels | Page 5 | PriusChat

 

I think monitoring is a good thing. And is absolutely necessary if you have bought or leased a system with a performance guarantee. While the inverter itself keeps track of much power is being generated, it tends to be a bit optimistic. A separate monitor allows me to check the health of the system when I'm not at home when the system is actually running, which is pretty much all the time. It also allows me to see hour by hour what's going on. Also, it's nice to be able to show people just what the system is doing. I obsessed about checking it constantly for the first month or so, but I'm over it now. I

Our system is 4.94 kW DC / 4.31 kW AC. It's installed on our east facing roof at 116 degrees. Sungevity guarantees 5900 kWh annually. PVWatts is more optimistic at about 7000 kWh annually. We're fairly confident that Sungevity will still be around 10 years given the fact that they are a pretty major player in the residential market and have good sources of funding.

 

Sure, one of the issues with off-angle sun, is that more of it get reflected, a coating might mitigate that some. But that all takes place after my calculations, in which I assumed 100% absorption and 100% efficiency. The real losses aren't as great as some people think. Especially given the paranoia with which people siting $15-$20 a peak watt panels worried about it. Siting $1 per peak watt panels seems to ease that paranoia some , but some people only grasp the emotion not the math. Perhaps the thing to say is that the real loss per dollar spent, is greatly reduced.

 

Not sure what you mean by 100 percent efficiency because no panels are anywhere near even ½ of that level of efficiency. Even if panel efficiency does get that high some day - efficiency ratings turn on perpendicular angle of the sun to the panel. That only happens for a very brief time of each day during summer - and only near the equator. But of course it's so hot at the equator ( sea level) you'd lose efficiency as panels do, when they get hot. Thus, Your system gets its rating based off of all of those factors - latitude - average temperatures in summer winter - average cloudy days - direction and angle of the array.
A real world example (using our system) to consider - 36panels - 225 DC watts, minus almost 4% dc to AC Conversion loss, minus ZERO days per year being perfectly angled at 90 degrees being located So Cal, etc. All of that drops us to what would otherwise be a 7.3kW array, down to a 7.1kW AC rating. But if rating arrays were truly honest, they would then factor in early morning late afternoon azimuths - because after all ... over 85% of your day - the sun will be up less than 50 degrees in the sky here on the North American continent - averaged through summer and winter.
So in reality the PV Array rating system is simply a measurement by which you can base other folks' systems to the one you have, or are considering.

SGH-I717R ? 2

 

It was a thought experiment. Read the original post, hopefully it will make sense.