Comment by tpoindex
27 minutes ago
I have a 19 year-old, roof mounted, 6.3 kW nominal system in two arrays (east/west facing), 40 deg. north. I've never washed the panels outside of rain and occasional hail storm "scrubbing". Replaced a failed inverter two years ago.
My peak summer output is basically the same as when installed, making 36-38 kWh on a cloudless day. I'm actually impressed my panels haven't really degraded in performance over those 19 years.
That's really impressive and well built solar system, for it to last thta long. It shows how durable quality panels are. I have a 6 month old ~3.7kW system (6 panels in total), planning on installing another 6 very soon. My house is surrounded by trees so it's been a bit of a struggle in the winter.
What the panels' technology / manufacturer?
SolarWorld, 175 watt, polycrystalline. I don't recall any model number (paper work is filed away somewhere.) ISTR mine were made in Germany. I think at the time my system was installed, there where some 225 watt panels available, but the 175 ones were a better price point per watt.
[edit - added technology]