Set tilt targets that improve output and returns. Compare seasonal angles and roof limits fast. Download results as CSV or PDF for sharing later.
Sample inputs and typical outputs for illustration.
| Latitude | Season | Mount | Selected Tilt | Recommended Tilt | Loss (est.) | Annual Energy | Annual Savings |
|---|---|---|---|---|---|---|---|
| 34 | Annual | Adjustable | 34 | 34 | ~0% | ~6,860 kWh | ~$1,372 |
| 40 | Winter | Fixed | 30 (roof) | 55 | ~12% | ~6,160 kWh | ~$1,232 |
| 25 | Summer | Adjustable | 10 | 10 | ~0% | ~7,000 kWh | ~$1,400 |
A small change in tilt can shift annual production, which affects cash flow. If your household values predictable bills, target the recommended angle first, then stress‑test alternatives. For example, a 5 kW system producing 1,400 kWh per kW-year yields about 7,000 kWh before losses. At $0.20 per kWh, that gross value is $1,400 per year, useful for planning.
Seasonal tuning matters when winter or summer demand dominates. This calculator applies a simple seasonal offset: winter adds 15 degrees, summer subtracts 15 degrees, and spring/fall stays near latitude. In practice, a 40 degree latitude site may favor roughly 55 degrees in winter for stronger low‑sun capture, while a summer focus may sit closer to 25 degrees to reduce midday reflection losses.
Facing direction can be as important as tilt. The azimuth offset measures how far the array points away from true south. If your roof points west by 45 degrees, the model applies a proportional penalty, lowering expected output. This highlights why a slightly imperfect tilt may be acceptable if the orientation is strong, while large azimuth errors can dominate the loss budget.
The energy estimate combines baseline production with system size, then reduces output by modeled losses. Because rate structures vary, the savings figure is a clean starting point rather than a guarantee. Use your local tariff, then compare savings against installed cost to see simple payback. If incentives apply, adjust cost downward to reflect rebates or credits before evaluating return.
Use results as a decision aid. Choose a fixed tilt when roof constraints exist, or an adjustable tilt when seasonal optimization pays off. Confirm shading, row spacing, and inverter limits with a professional. If two options deliver similar output, prioritize the one with lower hardware risk, easier maintenance, and clearer warranty coverage over small modeled gains.
Track actual monthly bills for three cycles, then recalibrate baseline production. If you export CSV results, record assumptions like latitude, azimuth, and rate so comparisons remain consistent over time, even after upgrades carefully.
A practical starting point is near your absolute latitude. This calculator adjusts for season focus and then compares your chosen or roof tilt to that target to estimate energy and savings.
They are planning estimates based on tilt difference and azimuth offset. Real performance depends on irradiance, shading, temperature, soiling, wiring, and equipment efficiency. Use measured production when available.
Yes. If your array points east or west of south, output shifts through the day. Enter the offset to estimate the orientation penalty and see whether adjusting tilt can partially compensate.
Use a local benchmark or your installer’s expected kWh per kW-year. Regions vary widely. If you already have system data, divide annual kWh by system kW to derive a site‑specific baseline.
Fixed roof mounts usually follow the roof plane. By entering roof pitch, the calculator treats it as the selected tilt, then shows how far it deviates from the recommended seasonal or annual target.
Payback is installation cost divided by estimated annual savings. It ignores financing, maintenance, degradation, and incentives unless you adjust inputs. Use it as a quick comparison, not a full investment model.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.