A photovoltaic installation bought by an entrepreneur can reduce income tax, but usually not in the month of purchase — gradually, through depreciation write-offs. The result depends on three things: whether the electricity from the panels powers the business, whether the installation is part of a building or a separate device, and which form of taxation was chosen. Below we discuss these conditions on the legal status of 2026.
When panels are linked to the business
The expense for the installation is accounted for in the business when the energy from it serves revenue: it powers a hall, workshop, office, cold store or charger of the company car, or lowers the bills for premises the entrepreneur rents to others within the business. The mere fact that panels sit on the roof of the owner's house is not enough. If the electricity is used mainly by the household, the expense is private.
The value of the investment is not only the modules. The inverter, support structure, cabling, energy storage bought together with the installation, design, assembly and connection fees also count. All these items are worth having on invoices issued to the business.
Part of the building or a separate asset
This is the key classification, as it determines the speed of settlement.
Installation as a building upgrade
Modernisation of the building applies mainly to panels integrated with the roof structure (e.g. forming the roof covering); KIS interpretations usually treat a typical roof-mounted installation as a separate fixed asset (KŚT 669). Under Article 22g(17) of the PIT Act, an upgrade occurs when expenditure on conversion, extension, adaptation or modernisation in a given year exceeds PLN 10,000 and increases the utility value of the facility. The cost of the installation then raises the initial value of the building and is depreciated together with it, for a non-residential building as a rule at 2.5% a year. The settlement therefore lasts a very long time.
Installation as a standalone device
An installation that can be dismantled without damage to the building and moved elsewhere (e.g. on a free-standing structure on the ground or on a frame not permanently connected to the roof) is easier to treat as a separate fixed asset. It is then entered into the register under the appropriate symbol of the Classification of Fixed Assets and depreciated at the rate for that group, higher than for buildings. The choice of symbol is worth agreeing with the accountant before putting the installation into use, as later change can be problematic.
One-off write-off — when it is possible
When the photovoltaics is a separate fixed asset, the rules allow a faster settlement. Two routes from Article 22k of the PIT Act exclude each other for the same purchase:
- de minimis aid (paragraph 7) — for firms in the year of starting their activity and for small taxpayers, i.e. those whose sales revenue with VAT did not exceed the equivalent of EUR 2 million in the previous year; the write-off applies to groups 3–8 of the Classification (excluding passenger cars) and the limit is the equivalent of EUR 50,000 per year;
- write-off up to PLN 100,000 (paragraph 14) — for factory-new fixed assets from groups 3–6 and 8, with a value of at least PLN 10,000 (or at least two items bought in a year, totalling at least PLN 10,000 and each above PLN 3,500).
Neither of these paths covers a situation in which the panels increased the value of the building. Using de minimis also requires settling the public aid received, which matters when applying for other subsidies.
Residential house and grants — the main traps
Many entrepreneurs run their business at home. In 2026 residential buildings and premises used in the business are not subject to depreciation (Article 22c(2) of the PIT Act). If the installation is treated as an upgrade to such a house, there will be no write-offs on it. For an installation treated as a separate device, it must then be shown what part of the energy goes to the business and only that part is accounted for. In such cases it is sensible to protect oneself with an individual tax interpretation.
The second trap is co-financing. Write-offs on that part of the value which was covered by a grant or other refund are not a cost (Article 23(1)(45)). If an installation for PLN 50,000 received PLN 15,000 of support, depreciation in costs applies only to PLN 35,000.
For a private single-family house, the alternative is thermo-modernisation relief: up to PLN 53,000 of deduction for all undertakings in the taxpayer's buildings (Article 26h). The same expense cannot, however, be deducted twice — an amount included in business costs will no longer go into the relief. The relief can also be applied by persons on ryczałt, deducting expenses from revenue.
VAT and ryczałt
An active VAT payer deducts the VAT from the installation invoice to the extent it serves taxable sales (Article 86(1) of the VAT Act). For mixed use (business and home), the deduction should correspond to the business share. The invoice rate depends on the place of assembly: the reduced 8% applies to works in buildings covered by the social housing programme, and in other cases, e.g. on a production or office building, 23% is applied.
Under ryczałt on recorded revenue, depreciation does not reduce the tax. A person using this form may only deduct VAT (if they are an active VAT payer) and benefit from lower energy bills.
Example: carpentry workshop
An entrepreneur on the flat tax, a small taxpayer, in 2026 installs a factory-new system on a free-standing structure next to the workshop. The net cost is PLN 60,000; VAT at 23% (PLN 13,800) is fully deducted, because all the energy powers the machines. The installation is accepted as a separate fixed asset. By choosing the write-off up to PLN 100,000, PLN 60,000 can be charged to costs in the year of entering into the register, which at 19% reduces the tax by PLN 11,400. If the panels were permanently fixed in the hall's roof, the same amount would raise the building's value and spread over many years.
How Good Balance can help
As part of simplified accounting, we determine the classification of the installation, keep the fixed asset register and choose the depreciation method. For a business run at home or with a grant, we help prepare an application for an individual tax interpretation, and we advise those planning a new business as part of sole proprietorship handling.