Solar panels on my roof 3 years ago vs now - the dropoff is real

I put up 12 panels on my house in Phoenix back in 2021. First year my electric bill went from $180 a month down to about $15. Now I'm looking at $90 a month because the panels are producing maybe 60% of what they did. The inverters are fine, but I think dust buildup and some shading from a neighbor's new tree is killing output. You think regular cleaning is worth the hassle or are these things just overhyped after a few years?

3 comments

3 Comments

milam487d ago

and another thing about that neighbor's tree, have you thought about trimming it yourself? I mean yeah cleaning helps but if that tree is blocking morning or afternoon sun then you're losing way more than dirt can cause. I know people in Tucson who clean every 3 months and still see a 20% drop from trees they didn't think mattered. Phoenix dust is brutal too but a good rain usually washes some of it off. Your 60% number sounds like shading is the real problem not just grime. Maybe check if the tree needs a trim on your side before you go buying a hose and brush.

parkerbrown7d ago

lol yeah I tried trimming my own tree once and ended up looking like I lost a fight with a hedge trimmer. But seriously you're probably right about the shading thing, I bet I'm just kidding myself thinking it's all dust.

the_alice5d ago

Milam48 I get where you're coming from but I've got to disagree on this one. My neighbor has a big old mesquite that shades my panels from about 11am to 3pm in the summer, and I actually see a bump in production during those hours compared to winter when the sun is lower. The panels still generate plenty of power from the diffuse light, and the cooling effect of the shade actually bumps efficiency up by about 5% according to my monitoring. I trimmed one branch a couple years ago and my afternoon production barely budged, but my house got a lot hotter. Shade isn't always the enemy, sometimes it helps more than it hurts.