Photovoltaic System Calculator
Fast, accurate and free online paneli solarnych calculator tool running directly in your browser.
-
1Enter data
Enter content, paste text or load a file from disk. -
2Click the button
The tool will immediately process your data in the browser. -
3Get the result
Copy the finished text or save the file to your device.
return "Result ready in 0.1s";
}
Rate this tool:
Related tools
Other tools you may find usefulSolar panel calculator – how to calculate the power of a photovoltaic installation?
In times of rising electricity prices and growing ecological awareness, investing in renewable energy sources (RES) has become one of the most profitable steps for households and companies. Photovoltaics (solar panels / PV) allows you to generate free electricity from solar radiation. The key to a quick return on investment (ROI rate) is the correct selection of installation power. Too small an installation will not cover the demand and will force us to purchase expensive electricity from the grid. In turn, an oversized installation (too large) will generate high initial costs, and surplus electricity will be fed into the grid at unprofitable rates (especially in the net-billing system). Our free **online solar panel calculator** allows you to precisely determine the optimal power of your photovoltaic installation and calculate the number of panels needed based on your annual electricity bill.
Thanks to this, you will find out what size of installation you need, how much space on the roof the panels will take up and what the estimated cost of the entire investment will be.
Comparison of solar panel technologies - monocrystalline vs. polycrystalline
The choice of the type of photovoltaic cells directly affects the efficiency of the entire installation and the roof area that must be allocated for installation. The table below shows a comparison of the most popular technologies:
| Type of photovoltaic panels | Cell efficiency (%) | Appearance and aesthetics | Temperature coefficient | Advantages | Disadvantages |
|---|---|---|---|---|---|
| Monocrystalline(standard market) | 18% – 22% | Uniform, dark color (black/dark navy blue). | Low (copes well on hot days, loses power slower). | Very high efficiency, smaller roof area per 1 kWp, long service life. | Higher purchase price per single panel. |
| Polycrystalline(older technology) | 14% – 16% | Blue tint, visible silicon crystal structure. | Higher (lose efficiency faster when heated by the sun). | Lower purchase price, good price-performance ratio with no space limitations. | They require a larger roof area to obtain the same power as monocrystalline panels. |
| Thin-layer(e.g. CIGS) | 10% – 13% | Uniform, smooth black surface, flexible structure. | Very low (very stable in extreme heat). | They work well in weak, diffused light, low weight, aesthetic appearance. | Very low efficiency, require a huge installation area. |
Methodology for calculating installation power (Formula and rules)
The basis for calculating the power of a photovoltaic installation in Poland is the annual electricity consumption expressed in kilowatt hours (kWh). On average, it is assumed that in Polish climatic conditions, from **1 kWp (kilowatt-peak) of installed power, we will receive approximately 1,000 kWh of energy per year** with the optimal inclination of the panels at an angle of 35 degrees towards the south.
Due to the costs of energy balancing in the network (loss coefficient for auto consumption and settlements), the installation power is calculated according to the formula:
$$P_{\text{install}} = \frac{E_{\text{annual}} \times 1.2}{1000}$$
Where:
- $P_{\text{install}}$ – required installation power in kWp.
- $E_{\text{annual}}$ – annual household electricity consumption in kWh.
- $1.2$ – correction factor (increase in power by 20% to compensate for losses when balancing electricity in the network and auto consumption).
Example: Your farm consumes 4,000 kWh of electricity per year. $$P_{