6 kWp solar system: cost and payback
The calculator starts from a 6 kWp system in a 150 m² house with a heat pump that uses about 7,433 kWh of electricity a year. At PLN 5,600 per kWp the system costs about PLN 33,600, saves about PLN 3,122 a year and pays back in about 10.8 years.
Example: 6 kWp, the house uses 7,433 kWh a year
Simple payback: about 10.8 years
saves about PLN 3,122 a yearabout PLN 260 a monthcost after relief and grants about PLN 33,600
- Used straight away: 1,950 kWh, 33%
- Exported: 4,050 kWh, 68%
Power you do not buy: about PLN {avoided}. The deposit for exported energy covers about PLN {deposit} of your bills.
Cumulative balance over 25 years
After 25 years: about PLN 36,091
With degradation and upkeep the balance turns positive for good after about 12.8 years.
Electricity price from 11 October 2026, estimate
| Year | Output | Saving | Costs | Balance |
|---|---|---|---|---|
| Year 1 | 6,000 kWh | 3,122 PLN | 0 PLN | −30,478 PLN |
| Year 5 | 5,881 kWh | 3,084 PLN | 0 PLN | −18,087 PLN |
| Year 10 | 5,735 kWh | 3,036 PLN | 0 PLN | −2,810 PLN |
| Year 12 | 5,678 kWh | 3,017 PLN | 5,500 PLN | −2,265 PLN |
| Year 15 | 5,593 kWh | 2,989 PLN | 0 PLN | 6,729 PLN |
| Year 20 | 5,455 kWh | 2,941 PLN | 0 PLN | 21,530 PLN |
| Year 25 | 5,320 kWh | 2,893 PLN | 0 PLN | 36,091 PLN |
Assumptions and formulaElectricity price from 11 October 2026
output = 6 kWp × 1,000 kWh = 6,000 kWh used on site = 1,950 kWh, exported = 4,050 kWh, bought = 5,483 kWh saving = 1,950 kWh × PLN 1.04 + deposit PLN 1,094 = PLN 3,122 a year payback = PLN 33,600 ÷ PLN 3,122 = 10.8 years
- Yield per kWp
- 1,000 kWh/kWpPVGIS 5.3 (JRC): Warsaw, south roof at 35°, about 1050 kWh per kWp, 1000 to be safe
- Price per kWp
- 5,600 PLN/kWpKB.pl, solar prices 2026: PLN 5200-6300 gross per kWp
- Electricity price
- 1.04 PLN/kWhURE G11 tariffs 2026 (PGE, Tauron, Enea, Energa), average with distribution
- Value of 1 kWh exported
- 0.27 PLN/kWhPSE RCEm for April-July 2026 weighted by PV output, times 1.23
- Part of the bill the deposit covers (G11 energy)
- 0.62 PLN/kWhG11 energy prices of default suppliers, URE Masz Wybór comparison
- Deposit: multiplier and refund of unused money
- × 1.23, refund up to 30%
- House with heat pump
- 33 %KosztyDomu.pl hourly simulation on PVGIS 2020-2023 data, Warsaw, 1000 kWh/kWp
- Panel degradation
- 0.5 %/yrNREL, Photovoltaic Degradation Rates: median 0.5% a year
- Inverter replacement
- 5,500 PLNSystemy-fotowoltaika.pl: 5 kW inverter replacement with fitting PLN 5000-6000
- Thermal modernisation relief
- No relief
An estimate. Self-consumption comes from a simulation of a typical house near Warsaw, with net billing settled over a year. Fixed charges, changes in the law and battery replacement are not included. Compare at least three offers before you buy.
How electricity, gas, pellet and coal prices have changed, month by month. Price history
Ready-made calculations
How to use the calculator
- Enter your yearly electricity use from the last 12 months of bills. If you plan a heat pump or an electric car, add their use.
- Enter the system size and the price from your quote, per kWp or in total. Below the size you will see the upper limit of a sensible size for your use.
- Choose whether the house has a heat pump. The calculator then estimates self-consumption from our hourly simulation. If you know yours, set it on the slider.
- Check the electricity price and the value of exported energy, pick your thermal modernisation relief rate and add a home battery if you want one.
- Click Calculate payback. The result keeps updating as you change inputs, and you can copy a link to it.
6 kWp with and without a heat pump
A heat pump runs around the clock, so the house uses about 1,950 kWh of the 6,000 kWh output straight away, 33%. The saving is about PLN 3,122 a year and the payback about 10.8 years, or about 9.5 years with the 12% relief.
The same system in a house without a heat pump that uses 4,000 kWh saves about PLN 2,721 a year and pays back in about 12.3 years, because more of the output goes to the grid. If you have no heat pump, enter your use and choose the house without a heat pump.
Paperwork for 6 kWp
A 6 kWp system stays below the 6.5 kW threshold above which the design needs approval from a fire safety expert and the fire service must be notified. A notification to the grid operator is enough, and the installer usually files it.
Frequently asked questions
How much does a 6 kWp solar system cost in 2026?
According to the KB.pl price review, about PLN 31,200-37,800 gross with fitting and 8% VAT. The calculator uses PLN 5,600 per kWp, which is PLN 33,600. Enter your quoted price and the result updates straight away.
Is 6 kWp enough for a house with a heat pump?
On paper it covers about 6,000 kWh of about 7,433 kWh of yearly use, but a heat pump uses most in winter, when panels produce little. In our simulation the house uses about 1,950 kWh of output straight away and exports the rest into the deposit.
How long does a 6 kWp system take to pay back?
In a house with a heat pump about 10.8 years, or about 9.5 years with the 12% relief. In a house without a heat pump using 4,000 kWh, about 12.3 years.