The Data I Promised Myself I’d Track
When my system went live on January 12th of last year, I told myself I’d log every single month’s production numbers. This complements my full 14-month ROI analysis — these are the raw production inputs behind those financial numbers. Not because I’m obsessive (okay, maybe a little), but because my installer gave me a 25-year production estimate and I wanted to know if I was actually getting what I paid for.
My system: 10.2 kW, 24 Qcells Q.PEAK DUO panels, SolarEdge inverter, south and west-facing roof, central Ohio (Columbus area, about 40.0°N latitude). Installer’s Year 1 production estimate: 11,400 kWh.
Here’s what actually happened, month by month.
Month-by-Month Production: Year One
January (12 days operating): 82 kWh
The system went live on January 12th, so this is only 20 days of production. Annualizing, that’s about 6 kWh/day — which is actually consistent with what January delivered all month. Ohio in January is brutal for solar. Short days, low sun angle, frequent cloud cover. We had three stretches of 3–5 consecutive cloudy days.
February: 280 kWh
February surprised me. We got a stretch of clear cold days in mid-February that pushed production up. Cold temperatures actually help panel efficiency — solar panels lose efficiency in heat, so a cold, clear February day can outperform a hot, hazy July afternoon on a per-sun-hour basis. Still, 280 kWh for the month, with my house consuming about 1,100 kWh, meant I was still pulling heavily from the grid. Net metering credits: essentially zero — I used everything I produced and then some.
March: 680 kWh
March was the first month where I started to feel the system working. Longer days, higher sun angle, and we had two solid weeks of good weather. 680 kWh represented about 62% of my household consumption that month. I sent a small amount back to the grid toward the end of March.
April: 1,020 kWh
April was where the system really started performing. 1,020 kWh produced vs. roughly 950 kWh consumed — my first month where I generated more than I used. Net metering credit: approximately 70 kWh banked. My utility bill dropped to $12.47, which was just the fixed monthly customer charge.
May: 1,180 kWh
Strong month. 1,180 kWh produced, about 870 kWh consumed (AC hadn’t kicked in yet), net metering credit built to about 380 kWh banked. Still no utility bill beyond the customer charge.
June: 1,340 kWh
My best month of the first half of the year. Long days, frequent sun. We ran the AC regularly starting in mid-June, which pushed consumption up to about 1,150 kWh — but I still netted about 190 kWh of credits. Cumulative net metering bank: ~570 kWh.
July: 1,290 kWh
July was hot and hazy — Ohio summers often get this way, and the heat and humidity reduce panel efficiency more than people expect. I’d hoped for 1,400+ kWh in July, but the haze and heat kept it at 1,290 kWh. Consumption was high (1,350 kWh) due to heavy AC use, so I actually drew about 60 kWh net from my banked credits. Still not paying an actual electricity bill.
August: 1,210 kWh
Similar story to July — heat and humidity limited production. 1,210 kWh produced, about 1,280 kWh consumed. Slightly net negative month, drawing down my credits further. Bank now at about 440 kWh. This was the first month I started understanding that summer in Ohio is not a solar paradise. It’s good, but it’s not Arizona.
September: 1,050 kWh
September was excellent. Temperatures dropped, skies cleared, and the sun angle was still decent. 1,050 kWh produced, consumption dropped to about 820 kWh (AC mostly off). Net credit addition: 230 kWh. Bank rebuilt to ~670 kWh. This was probably my most efficient month in terms of production relative to conditions.
October: 760 kWh
The long fade begins. Days getting shorter, sun angle dropping. 760 kWh produced, about 900 kWh consumed (furnace beginning to run, though not heavily). Drew down 140 kWh from credits. Bank at ~530 kWh heading into fall.
November: 380 kWh
November was rough. Several multi-day overcast stretches and significant rain. I wrote more about how Ohio solar systems perform in cloudy climates if you want to understand the seasonal variance better. 380 kWh produced, about 1,050 kWh consumed (heating season in full swing). Drew 670 kWh from banked credits — wiped out most of my summer bank and then some. Utility bill came back: $14.20 for about 140 kWh of grid import beyond my credits.
December: 180 kWh
December was exactly as brutal as I expected. Shortest days of the year, overcast most of the month, one significant snow event that covered the panels for four days. 180 kWh produced, about 1,180 kWh consumed. Net grid import: about 1,000 kWh. Utility bill: $131.47 for December — highest of the year, similar to pre-solar December bills. The solar system was basically irrelevant to my December energy costs.
Full Year Summary
| Month | Production (kWh) | Consumption (kWh) | Net |
|---|---|---|---|
| January (partial) | 82 | ~800 (partial) | -718 |
| February | 280 | 1,100 | -820 |
| March | 680 | 1,100 | -420 |
| April | 1,020 | 950 | +70 |
| May | 1,180 | 870 | +310 |
| June | 1,340 | 1,150 | +190 |
| July | 1,290 | 1,350 | -60 |
| August | 1,210 | 1,280 | -70 |
| September | 1,050 | 820 | +230 |
| October | 760 | 900 | -140 |
| November | 380 | 1,050 | -670 |
| December | 180 | 1,180 | -1,000 |
| Total | 9,452 | 12,550 (est.) | -3,098 |
Note: Full-year production of 9,452 kWh reflects 20 days of January missing. Annualized, the system is on pace for approximately 9,970 kWh — about 12.5% below the 11,400 kWh estimate.
Why I Was Below the Production Estimate
That 12.5% shortfall concerned me enough to call my installer. After some investigation, they found a suboptimal string configuration — one of my panel strings was wired in a way that reduced efficiency during partial shading conditions. This was corrected remotely in Month 7. If I annualize just the last six months of the year (post-correction), I’m on pace for about 11,100 kWh — much closer to the estimate.
The takeaway: production estimates are models. Real-world numbers will differ based on actual weather, any installation issues, and shading conditions that weren’t fully modeled. That’s why monitoring matters — I found a real problem because I was tracking real numbers.
The Net Metering Math
Over the full year, my utility credits roughly offset my bill. Here’s the simplified version:
- Grid import for the year: approximately 5,200 kWh
- Grid export (net metering credits): approximately 2,100 kWh
- Net grid draw: approximately 3,100 kWh
- Net grid cost at $0.13/kWh: approximately $403 for the year
- Pre-solar, I was paying approximately $1,764/year ($147/month)
- First-year savings: approximately $1,361
Lower than the projected $1,482 due to the production shortfall, but still a substantial reduction. And now that the configuration issue is corrected, Year 2 should be closer to the estimate.
What I’d Tell Someone Considering Solar in Ohio
Go in with realistic expectations. Ohio is not a bad solar market — our production numbers are solidly in the “viable” range. But we’re no Arizona. You will have a December where your solar system barely registers. You will have cloudy November weeks where it feels like you’re paying for panels that aren’t doing anything. I also keep up with routine checkups — my solar panel maintenance guide covers what actually needs attention (less than you might think). The math still works over a year — you’re producing the majority of your power from April through September, and that’s when your biggest bills would be anyway. But it’s not a straight-line savings story. It’s seasonal, and the winter months are humbling.