What changes on 1 January 2029

The Federal Council confirmed on 1 April 2026 that the reform will enter into force on 1st of January 2029, later than some had expected, reflecting cantonal finance directors preference for no earlier than 2029. For an owner-occupied home, five changes matter most.

• The imputed rental value (Eigenmietwert, valeur locative) on owner-occupied primary and secondary homes is abolished.

• The general deduction for property maintenance costs disappears at federal, cantonal and municipal level, for owner-occupied residential property.

• The federal deduction for energy-saving and environmental investments is also abolished; cantons may continue to allow it for a limited period under their own rules.

• The deduction for private debt interest, mortgages included, is substantially restricted, with a limited exception that remains for qualifying first-time buyers of an owner-occupied home.

• Cantons gain the option to introduce a special property tax on second homes that are predominantly owner-occupied.

What this means for renovation costs

Under the current system, some costs of maintaining a privately owned home can be deducted from taxable income. The distinction that matters is between work that preserves a property’s existing value and work that adds to it.

Value-preserving work

Maintenance and replacement that keeps a property at its existing standard, repairing what is worn, replacing like for like can currently qualify, subject to the federal and cantonal rules that apply.

Value-enhancing work

A higher specification, an extension, a new feature or a substantial upgrade is treated differently, and may be only partly deductible or not deductible at all. Most comprehensive renovations contain both: a new kitchen, bathroom, floor, window package or technical installation cannot simply be assumed deductible because it replaces something older. This is exactly the kind of distinction worth establishing with a tax adviser before the project scope is fixed, not after.

Not every upgrade is treated the same way by the tax office.

Why 2027 and 2028 may be important planning years

From January 1, 2029 the general deduction for maintenance costs on an owner-occupied home disappears. For homeowners already weighing substantial work, that makes 2027 and 2028 worth paying attention to.

This is not a reason to rush a renovation. Design, permits, technical planning, contractor availability and product lead times still matter far more than a possible deduction. But for a larger project, it is worth establishing the scope early and asking a tax adviser which parts of it may still qualify under the rules that apply before 2029.

Timing within the current system also matters. Deductible costs are generally counted in the tax year they are invoiced, and because the tax system is progressive, larger projects are often better spread deliberately across two or more tax periods rather than invoiced all at once. Smaller works can sometimes be grouped together to clear the deduction threshold in a single year. The right approach depends on the project and the household’s own tax position, which is exactly the kind of planning a tax adviser should structure alongside the renovation schedule, not after it.

The timeline is tightened further by the building trade itself. Bespoke carpentry, natural stone and premium fittings are routinely running three to four months from signed drawings to delivery, before installation even begins. Hence a project intended to be invoiced within the current system needs to be commissioned well ahead of the deadline, not decided at it.

Energy renovations deserve a closer look

The reform also changes how energy-saving and environmentally beneficial investments are treated. The federal deduction ends with the new system; cantons may continue offering their own version of it for a period, so the picture can differ depending on where a property sits.

For new windows, insulation, a heating system or other energy-related work, it is worth checking both the tax rules and any subsidy programmes that apply before settling on a timeline.

One detail worth knowing while the current system still applies: if an energy-saving investment costs more than can be offset against taxable income in a single year, the unused balance can currently be carried forward across the next two tax periods. For a substantial upgrade (a heat pump, triple glazing, a new building envelope) that carry-forward window is itself a reason to plan the investment and its invoicing with a tax adviser rather than leave it to the final year before the reform.

Cantonal positions on their own post-reform energy and heritage-preservation deductions are still developing; Vaud and Valais had not published their approach at the time of writing. This is a point worth checking directly with a tax adviser closer to the time, rather than assuming either canton will mirror the other.

Energy upgrades follow their own, separate set of rules.

What about a home you rent out?

Rented and leased residential property is treated differently under the reform. The deduction for maintenance costs remains available there, and the new, more restrictive rules on debt interest depend on the relationship between a rented property and an owner’s total assets. It is worth a separate conversation with a tax adviser if this applies.

What to do now, if a renovation is on the horizon

• Define the scope early, particularly for substantial work being considered for 2027 or 2028.

• Keep maintenance, replacement and value-enhancing work clearly separated in quotations and invoices.

• Document the existing condition, the proposed works, contracts and invoices as you go.

• Ask a qualified Swiss tax adviser which costs may be deductible for your situation and tax year.

• Discuss invoice timing with your adviser, whether a larger project is better spread across tax periods or grouped into one, and how any energy-saving carry-forward applies to your situation.

• For energy-related work, check both the tax rules and the incentive programmes in your canton.

• Start the design and technical planning well ahead of time, a high-quality renovation needs many months of preparation before construction even begins.

Planning beyond the tax question

Tax timing is only one part of planning a renovation well. The projects that go smoothly start with a clear read of the property itself: the layout, the technical constraints, the budget and the realistic timeline.

For anyone buying a property that will need work, this is where it helps most to look early: understanding the likely scope and investment before committing, so the design, the financing and the construction programme can be planned together. Any decision made for tax reasons in 2027 or 2028 should result in a home that was genuinely designed, not assembled under a deadline.

A renovation planned properly outlasts whichever tax year it happened to finish in.

This overview is general information, not tax or legal advice — the deductibility of any renovation depends on the specific project and the applicable federal and cantonal rules, which is why we always recommend confirming the detail with a qualified Swiss tax adviser before relying on it.

Sources: Federal Council communication, 1 April 2026 · federal popular vote, 28 September 2025, official result · UBS Switzerland, “How does the imputed rental value work?” and “Tax deduction for renovation costs” · energy-investment carry-forward, DBG art. 32 para. 2bis (SR 642.11).