End of rental value in 2029: what changes for solar deductions, cantonal rules and the renovation schedule for your house.
Should we install solar panels before 2029?
This can be advantageous, but the answer depends on the building, your taxation and the actual schedule of the work. A tax saving can improve a well-sized project. It does not transform an overly expensive installation, a roof to be redone or poorly estimated consumption into a good investment. Compare two offers and two completion dates based on the same technical assumptions.
The Federal Council press release of April 1, 2026 sets the entry into force on January 1, 2029. Federal deductions for energy savings and environmental protection will disappear. The cantons will be able to keep these deductions for a limited period. It is therefore necessary to distinguish federal tax from cantonal treatment, without assuming that all the advantages stop everywhere at the same time.
What changes for your solar decision
Photovoltaics combines several financial flows: payment for the installation, possible subsidy, tax effect, avoided electricity purchases and injection income. These flows are neither paid together nor calculated by the same organization. The disappearance of a deduction does not automatically eliminate investment aid, and a subsidy does not guarantee identical tax savings for each household.
To prepare your budget, separate the gross cost and confirmed aid. Then add a tax estimate calculated for your situation. Finally, examine the operation of the installation over several years. This presentation allows us to understand whether the interest in moving forward with the work comes from a truly accessible tax advantage or from an optimistic hypothesis included in a quote.
The order date should not become your only benchmark. Ask the tax office or your advisor which event determines the deduction year in your case: work, invoicing, payment and applicable rules must be examined together. Do not assume that a deposit paid at the end of 2028 alone secures a deduction for an installation carried out later.
Occupied house, rented accommodation or secondary residence
Start by identifying the use of the property. A home you live in, a rented building and a mixed-use building should not automatically share the same calculation. A change of use or a planned sale can also change the interest in carrying out the work now. Clarify the distribution of expenses when only part of the building is occupied by its owner.
For rented accommodation, the Federal Council specifies that the deduction of maintenance costs remains maintained. This is not enough to qualify each solar station as a maintenance cost: it is still necessary to examine the expense and the applicable tax regime. For a second home, add any cantonal measures linked to the reform. Just the word “house” in a quote does not describe your tax situation.
In PPE, the timetable also depends on joint decisions, cost distribution and calls for funds. Have the individual treatment of expenses validated with the co-ownership documents. An estimate for a detached house cannot be copied as is to each apartment.
How to quantify the tax saving without overestimating it
A deduction reduces taxable income; it is not a discount of the same amount on the invoice. The correct calculation compares the tax due with and without the allowable expense. A single commercial percentage risks mixing several taxes or applying a rate to the entire expense that changes during the calculation.
Purely illustrative example: assume a confirmed deductible base of CHF 18’000. If the tax difference calculated with your complete situation reaches CHF 3’600, the tax effect here represents 20% of this base. This does not mean that all owners recover 20%, nor that this totality disappears in 2029. The federal share must be separated from the cantonal and municipal shares before comparing the calendars.
Also check that the grant has not been counted twice. The quote must show its treatment in the net cost and in the tax estimate. If an advisor mentions deferring expenses over several periods, ask explicitly how this mechanism and the transitional provisions apply to your file. Don’t arrange invoices based on a simple oral promise.
Renovate the roof and install solar in the right order
The first useful appointment can be that of a roofer. If the roof needs to be replaced soon, installing panels and then removing them increases the number of interventions. Conversely, redoing a still suitable roof just to accelerate a tax benefit can create a disproportionate expense. Request an assessment of the watertightness, structure and remaining service life.
Compare three variants: solar alone on a preserved roof, renovation and solar on the same site, or prior renovation with subsequent installation. For each, ask for scaffolding, possible removal, connection, control and responsibilities. Also consult our guide to redo your roof before solar.
The items must be sufficiently detailed so that their tax treatment can be examined separately. Insulation, covering, photovoltaic elements, battery and terminal are not necessarily treated in the same way. An invoice grouped under “energy renovation” does not replace the description of what was installed.
Advance work or conserve cash?
An installation can be interesting without having to be paid immediately. Keep a margin for building expenses and for unforeseen events revealed by the construction site. If you borrow, add interest, fees and schedule to the scenario. Compare the terms with our guide to financing a solar installation.
A household nearing retirement should calculate several years of income separately rather than automatically taking the nearest year. For a planned sale, distinguish the electricity savings made before departure from any added value at resale. The latter should not be considered as a guaranteed reimbursement of the price of the panels.
Request two legible simulations: achievement before the reform with documented eligible benefits; realization after with clearly identified tax assumptions. Keep the same power, the same consumption profile and the same quality requirements. Otherwise, you will be comparing different projects rather than the effect of the date.
A reasonable timetable from 2026 to 2028
In 2026, gather the data: electricity bills, roof condition, heating or electric car plans, taxable income and property horizon. Obtain an initial power estimate and ask for connection conditions. A battery must meet a measurable use, not only serve to increase an expense presented as deductible.
In 2027, compare offers and clarify authorizations, aid and tax treatment. If the roof or a PPE requires long steps, allow for a margin. A dated offer and a timetable conditional on connection are more useful than a vague commercial guarantee of installation “before the end of the regime”.
In 2028, check the remaining feasibility before committing. Demand a schedule, availability of equipment and a list of documents submitted. Do not accept backdating or artificial division of invoices. Keep the proof of completion and have the correct declaration of the work confirmed.
Documents to gather before signing
- The detailed quote, with VAT, exclusions and equipment references.
- The roof diagnosis and the renovation variant chosen.
- The estimate of aid, distinguishing between confirmed amounts and hypotheses.
- A personal tax simulation separating tax levels.
- The answer on the year of deduction and any carryovers.
- The conditions of the network manager and the implementation schedule.
- Payment, delay, receipt and guarantee rules.
Your decision is ready when the project remains understandable without its fiscal argument: expected production, on-site consumption, complete cost, quality of the roof and cash flow. The tax advantage can then help choose the schedule, with written assumptions that you can check at the time of declaration.