In short, Stockholm
- Paid back in
- 16.9 years The warranty is 10 years. Within the warranty in 0 of 20 cities; closest is Malmö with 11.6 years.
- Saves more a year
- 3 243 kr 20 panels (8.4 kW), 20,000 kWh a year, someone home in the day.
- Costs more
- 54 820 kr After the green tech deduction. It is 50% for a battery, but the panels use most of the 50 000 kr cap.
How the battery earns money
It saves money, but slowly. Four things decide.
- The reference house in Stockholm, 20 panels (8.4 kW), with a 10 kWh battery: saves 3 243 kr more a year, costs 54 820 kr more. Paid back in 16.9 years; the warranty is 10 years.
- The battery earns most by storing cheap night power for expensive hours; that is how our calculator runs it. The gap between cheap and expensive hours is what the battery earns on; the larger it is in your price zone, the more it saves.
- The deduction is 50% for a battery, but the panels use most of the 50 000 kr cap per person: one owner gets 27 533 kr (33%) for the battery. Two owners: more.
- Backup power needs an inverter with a backup function. For the fastest payback: wait with the battery.
The battery in all 20 cities
Within the warranty in 0 of 20 cities. Sorted by payback.
| City | Saves more/yr | Costs more | Paid back in | Within warranty? |
|---|---|---|---|---|
| Malmö | 4 727 kr | 54 820 kr | 11.6 years | No |
| Växjö | 4 644 kr | 54 820 kr | 11.8 years | No |
| Lund | 4 564 kr | 54 820 kr | 12.0 years | No |
| Helsingborg | 4 512 kr | 54 820 kr | 12.1 years | No |
| Halmstad | 4 428 kr | 54 820 kr | 12.4 years | No |
| Göteborg | 3 714 kr | 54 820 kr | 14.8 years | No |
| Karlstad | 3 612 kr | 54 820 kr | 15.2 years | No |
| Västerås | 3 533 kr | 54 820 kr | 15.5 years | No |
| Uppsala | 3 422 kr | 54 820 kr | 16.0 years | No |
| Norrköping | 3 360 kr | 54 820 kr | 16.3 years | No |
| Örebro | 3 347 kr | 54 820 kr | 16.4 years | No |
| Eskilstuna | 3 274 kr | 54 820 kr | 16.7 years | No |
| Jönköping | 3 265 kr | 54 820 kr | 16.8 years | No |
| Stockholm | 3 243 kr | 54 820 kr | 16.9 years | No |
| Linköping | 3 140 kr | 54 820 kr | 17.5 years | No |
| Borås | 3 103 kr | 54 820 kr | 17.7 years | No |
| Gävle | 3 104 kr | 54 820 kr | 17.7 years | No |
| Sundsvall | 1 476 kr | 54 820 kr | 37.1 years | No |
| Umeå | 1 296 kr | 54 820 kr | 42.3 years | No |
| Luleå | 1 129 kr | 54 820 kr | 48.6 years | No |
How the energy flows with a battery
The reference house in Stockholm with a 10 kWh battery, kWh per season.
Solar 465 kWh · sold 0 kWh · bought 7,254 kWh · saved 1 405 kr
The battery stored 0 kWh of solar and 888 kWh of cheap grid power, and gave 799 kWh back when power was expensive.
Solar 4,087 kWh · sold 795 kWh · bought 6,369 kWh · saved 6 698 kr
The battery stored 606 kWh of solar and 1,368 kWh of cheap grid power, and gave 1,771 kWh back when power was expensive.
Solar 3,432 kWh · sold 694 kWh · bought 363 kWh · saved 4 596 kr
The battery stored 864 kWh of solar and 37 kWh of cheap grid power, and gave 817 kWh back when power was expensive.
When a battery is still right
For backup power, a peak charge or two owners.
- Backup power: if you want power when the grid goes down, the battery gives it. It is a purchase for security, not for your wallet.
- Peak charge: Göteborg 49,00 kr and Karlstad 48,35 kr per kW a month on the highest hour. A battery can lower that peak. Our calculation does not count it, so the battery saves more there than the table shows.
- Two owners: the green tech cap is 50 000 kr per person and year. With two people on the invoice the battery gets its full deduction, 50% of 97% of the price, and pays back faster.
Questions and answers
Does a battery pay off?
Rarely for your wallet. In Stockholm, 10 kWh saves 3 243 kr more a year and costs 54 820 kr more: paid back in 16.9 years, and the warranty is 10 years. For backup power and more of your own solar: yes.
How large a battery should I get?
Our calculations have one size: 10 kWh. So we say nothing about other sizes here. In the calculator you choose the size for your own house.
What does the green tech deduction give for a battery?
50% of 97% of the price, at most 50 000 kr per person and year together with the panels. In Stockholm one owner gets 27 533 kr for the battery (33% of the battery's price), because the panels use most of the cap. Two owners get more.
The data
The data behind every number on the page, per month or year. Click a dotted number to open it.
With and without a battery, month by month
The battery moves cheap power and your own solar to expensive hours. The gain a year is the difference below.
| Month | Without battery | With 10 kWh | Difference |
|---|---|---|---|
| Jan | 268 kr | 432 kr | 164 kr |
| Feb | 602 kr | 745 kr | 143 kr |
| Mar | 875 kr | 1 115 kr | 240 kr |
| Apr | 780 kr | 1 137 kr | 357 kr |
| May | 1 070 kr | 1 300 kr | 230 kr |
| Jun | 1 291 kr | 1 610 kr | 319 kr |
| Jul | 1 030 kr | 1 406 kr | 376 kr |
| Aug | 1 160 kr | 1 580 kr | 420 kr |
| Sep | 1 179 kr | 1 540 kr | 361 kr |
| Oct | 732 kr | 955 kr | 223 kr |
| Nov | 345 kr | 651 kr | 306 kr |
| Dec | 124 kr | 228 kr | 104 kr |
| Year | 9 456 kr | 12 699 kr | 3 243 kr |
Roof facing south, 20,000 kWh a year, someone home in the day. kWh and kr per month.
Source: priv/data/city_solar/<city>.json · scenarios[id=S-20-b0-nocar-20-home|S-20-b10-nocar-20-home].months, savings_kr
The price line by line
The price incl. VAT minus the green tech deduction is what you pay. The battery reaches the 50 000 kr cap for one owner.
| System | Price incl. VAT | Green tech | To pay |
|---|---|---|---|
| 10 panels (4.2 kW) | 102 941 kr | −14 978 kr | 87 963 kr |
| 20 panels (8.4 kW) | 154 412 kr | −22 467 kr | 131 945 kr |
| 30 panels (12.6 kW) | 205 883 kr | −29 956 kr | 175 927 kr |
| 10 panels (4.2 kW) + 10 kWh battery | 185 294 kr | −50 000 kr | 135 294 kr |
| 20 panels (8.4 kW) + 10 kWh battery | 236 765 kr | −50 000 kr | 186 765 kr |
| 30 panels (12.6 kW) + 10 kWh battery | 288 235 kr | −50 000 kr | 238 235 kr |
Numsolar's example price list for installers, 2026-11-10; green tech 15%/50% of 97% of the price, at most 50 000 kr per person and year.
Source: priv/data/city_solar/<city>.json · scenarios[*].price_kr, gron_teknik_kr; model.price_list · Skatteverket, grön teknik