Short answer
What you need to know first.
In Aargau, PV costs are not simply a blanket tax bonus. For existing private properties, investments for using renewable energy can be treated like property maintenance costs; generally, only self-borne costs after incentive contributions are deductible. Anyone choosing the flat-rate deduction in the PV year does not additionally claim the same actual costs. Feed-in credits for electricity delivered to the grid must be classified separately as income; according to Aargau guidance, solar power used directly and simultaneously by the owner is not taxed.
Important
This page is general guidance for PV projects in Aargau and does not replace individual tax, legal or incentive advice. Tax treatment depends on ownership form, building type, invoice items, incentive contributions, use case and current assessment practice. Binding information comes from the competent tax authority or qualified tax advice.
Decision points
What determines the right path.
The most important distinction is: existing building or new-build. The Aargau factsheet applies the deduction practice to private property and distinguishes energy and environmental measures in existing buildings from non-deductible capital or value-increasing costs. The tax question therefore belongs early in project planning, especially if roof renovation, extension or replacement construction coincides with the PV system.
Incentive contributions reduce the tax-relevant cost base. The factsheet states that for subsidised measures only the costs borne by the taxpayer can be deducted. For PV projects this means: Pronovo one-time remuneration and any municipal contributions must be documented separately from the gross quote, final invoice and payment records.
Actual costs and the flat-rate deduction are a choice per tax period and property. The Aargau factsheet describes the flat-rate deduction as an alternative to actual costs; anyone wanting to claim large PV invoices must prove them with receipts and must not mix that logic with an additional flat-rate deduction.
Battery storage, contracting and mixed projects need their own review. The Aargau factsheet treats contracting differently if the contractor remains owner of the system, and it does not list first-time battery installation in the same blanket way as the PV system itself. Anyone combining storage, wallbox, roof renovation and PV should have invoices separated cleanly.
Electricity revenues are not the same as self-consumption. Aargau guidance explains that credits for the full amount of energy delivered to the grid constitute taxable income; solar power consumed directly and simultaneously by the owner is not taxed. Monitoring and billing data help make this distinction traceable later.
Sequence
How the project stays cleanly managed.
- 1
Before the quote, clarify the building caseexisting private property, new-build, replacement construction, condominium ownership, rented property or business assets. This classification determines which tax logic can be reviewed at all.
- 2
Structure quote and invoice so they are tax-readablehave PV system, electrical work, scaffolding, roof work, battery, wallbox, planning, fees and any roof renovation shown separately where possible. This makes later assessment easier and avoids blanket mixed line items.
- 3
Document incentives separatelykeep the Pronovo application, payment confirmation and any further contributions. For tax purposes, the gross investment alone is not decisive; what matters is which costs were actually borne after contributions.
- 4
Choose the deduction method consciously for the tax yearactual costs with receipts or flat-rate deduction. For larger PV investments, the comparison matters; the definitive assessment belongs in the tax return or with the competent tax office.
- 5
Separate electricity revenues and self-consumption continuouslysave feed-in credits, grid-operator statements and monitoring data. This keeps it traceable which electricity went to the grid and which was consumed directly in the building.
- 6
Have special cases checked before filingcontracting, battery storage, condominium ownership, tenant electricity models, business assets, roof renovation or replacement construction can change the classification. A general guide is not enough here.
Checklist
Questions to settle before the quote.
- Plan only self-borne costs after deducting incentive contributions
- Check actual costs instead of the flat-rate deduction for the PV year
- Document feed-in credits and direct self-consumption separately
- Do not treat new-build, contracting and storage cases the same by default
FAQ
Common questions on this topic.
Sources
Official sources & references.
The responsible authorities are decisive. Always verify binding details – amounts, deadlines and conditions – for your specific property against the current status of the respective authority.