Size.Solar
420W Solar Panel Production in Oslo
A single 420W solar panel in Oslo is estimated to generate approximately 346 kWh of electricity per year, averaging 0.95 kWh daily. This represents the actual AC power available for your home after system conversion losses.
Your system settings
Annual bill savings
$11,055
Save about $921 per month, capped to the 600 kWh/month use you entered.
Electricity use covered
48%
Produces an average of 288 kWh against 600 kWh of monthly use.
Annual output
3,460 kWh
Daily output
~9 kWh
System size
4.2 kW
Panels needed
21 panels*
Ready for a roof-specific design?
Turn this production estimate into a full project with roof layout, batteries, equipment, and supplier options.
Monthly production breakdown (kWh)
Project-ready estimate
Turn this result into a quote request
Start with 21 panels at 420W, about 8.8 kW, a 600 kWh/month bill target, and 14% modelled system losses. This gives suppliers the first inputs they need before roof layout, inverter limits, and battery choices are refined.
- Starter system
- ~8.8 kW
- Output per panel
- 346 kWh
- Bill value/year
- $1,106
- Weakest month
- Nov
21 panels for a 600 kWh/month home before roof, inverter, and battery constraints.
Estimated annual AC electricity from one 420W panel after modelled system losses.
Annual value at about NOK 3.20/kWh, capped to the electricity use you can actually offset.
2 kWh from one 420W panel; check this month before sizing essential loads.
Roof fit
Confirm usable roof planes, shading, inverter limits, and battery needs before accepting a final layout.
Bill fit
Adjust panel count and monthly use above so savings are capped to electricity you can offset.
Quote check
Ask suppliers to show winter output, assumed losses, and any export-credit value separately.
Production evidenceShow monthly output and model assumptionsOpen this when checking winter production, irradiance, losses, or the source assumptions behind the quote handoff.
Monthly model
Monthly output and winter risk
The calculator is useful when it shows the weak months, not just a flattering annual number. Use the table to check whether winter output still supports the loads you care about.
- Best month
- Jun
- Lowest month
- Nov
- Solar resource
- 3.0 kWh/m²/day
- Model checks
- 9.4%
50 kWh from one 420W panel
2 kWh from one 420W panel
1096 kWh/m² annual irradiance
Capacity factor, 31.6% performance ratio, 366 kWh DC before conversion
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 7 kWh | 18 kWh | 38 kWh | 43 kWh | 48 kWh | 50 kWh | 47 kWh | 42 kWh | 32 kWh | 17 kWh | 2 kWh | 3 kWh |
Model basis
The model uses south-facing panels at 60° tilt, true south orientation, and 14% system loss. Typical 600 kWh/month electricity costs are $960 - $2,380 (typically $1,917) using 2024-2025 cost data.
Solar production data provided by the PVWatts® API from NLR.