Real estateUpdated:
The short answer
Investments in energy efficiency and environmental protection on your own property can be claimed for tax purposes under certain conditions. The cantonal provisions and the type of measure are decisive. Careful documentation of the work and costs makes the declaration easier. If you are planning a renovation, you should find out about the tax treatment and any available subsidies at an early stage.
Which measures count as energy-related
Typical energy-related renovation measures include, for example, replacing windows, improving building insulation or switching to a more efficient heating system. Measures for the use of renewable energies can also fall into this category.
Not every structural improvement is automatically recognised as an energy-related measure. What matters is whether the investment actually contributes to improving energy efficiency or to reducing the environmental impact.
Measures to dismantle or replace oil heating systems with heat pumps, the installation of photovoltaic systems or work on the building envelope are also frequently among the recognised categories. Confirmation from the contractor carrying out the work regarding the type of work makes it easier for the tax authority to classify it later.
Tax treatment of such investments
In many cases, energy-related renovation measures are treated like value-preserving maintenance and can therefore be deducted from taxable income. In some cases, the costs can also be spread over several tax periods.
The exact rules, in particular whether and how such a spreading takes place, are regulated differently in each canton and should be checked in advance.
It is important to distinguish between a pure replacement measure, which is usually considered maintenance, and an increase in comfort or value that goes beyond this, which may in part be of a value-enhancing nature. This distinction is made by the tax authority in each individual case.
- Invoices for insulation measures and window replacement
- Evidence of heating system replacement
- Documents relating to renewable energy installations
- Confirmations from contractors regarding the type of measure
Spreading over several years
For larger energy-related investments, it may make sense to spread the costs over several tax periods, provided the canton allows this. This makes it possible to align the tax effect more closely with your current income.
Whether such spreading is possible and how it is applied for should be clarified with the competent tax authority or a specialist before the work begins.
Spreading the costs over several years can be particularly advantageous if your income is already lower in a single year anyway, or if spreading allows tax progression to be smoothed out over several years.
Interaction with subsidies
If cantonal or communal subsidies are paid out for energy-related renovations, these generally reduce the deductible costs. Only the costs you actually bear yourself can therefore be claimed.
It is advisable to document subsidy commitments and payments carefully in order to report the deductions correctly in the tax return.
Planning and timing of the investment
The timing of an energy-related renovation can have tax implications, for example if work is deliberately scheduled for a year with higher income in order to make optimal use of the deduction. Such planning should remain realistic and be guided primarily by the actual need for renovation.
For extensive projects, it is also worth involving an energy consultant who can assess both the technical and the financial side of the measure. This allows structural and tax considerations to be sensibly coordinated.
What you should have ready
- Invoices for all renovation measures
- Confirmations from contractors regarding the type of work
- Documents relating to subsidies received
- Details of the planned spreading of costs
- Evidence of the timing of the investments
- Cantonal forms or information sheets on energy deductions
Frequently asked questions
Sources
General information, not individual tax advice. Status: August 2026. The current guidelines of your canton and the official information of the tax authorities are decisive.
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