Taxes
Last call for the energy efficiency deduction: works must be finished by December 31
Royal Decree-Law 2/2026 extended until December 31, 2026 the deadline to deduct energy efficiency works on your main home from income tax. If you have a renovation underway, deadlines and energy certificates decide whether you deduct or not.
Source: Royal Decree-Law 2/2026 and the Spanish Tax Agency, 2026 income tax changes.
Key takeaways
Deducting 40% of a 10,000-euro window and insulation renovation means 4,000 euros off your tax bill, but only if the work finishes and is certified before year-end.
- The 20% deduction for cutting heating demand and the 40% one for cutting primary energy consumption require works completed before December 31, 2026.
- The 60% deduction for works on residential buildings has an extra year: it runs until December 31, 2027.
- An energy performance certificate is required before and after the works, issued by a qualified technician, and payment must be made by means other than cash.
Which deductions remain and until when
Three routes remain. The 20% one, for cutting heating and cooling demand by at least 7%, with a maximum base of 5,000 euros a year. The 40% one, for cutting non-renewable primary energy use by 30% or raising the rating to an A or B letter, with a maximum deduction of 3,000 euros a year. And the 60% one, for works on predominantly residential buildings, up to 5,000 euros a year.
The first two expire on December 31, 2026 for your main home or a home rented out as the tenant's residence; the 60% one lasts until the end of 2027. If the property is rented out, it must be let before December 31 of the year following the works deadline.
The requirements where most people trip up
The key requirement is paperwork: an energy certificate issued before the works (no more than two years old) and another afterwards, both registered. Without accredited improvement in demand or rating there is no deduction, however expensive the renovation.
Payments must also be made by transfer, card or cheque —never cash—, invoices must be issued to the taxpayer claiming the deduction, and the property must be a main home or rented for residential use.
Quick tips
- Request the initial certificate before signing the renovation: issuing it later with a backdated document invalidates the deduction.
- If the works are carried out by the owners' association (façade, roof), keep the minutes and your special levy receipt: the 60% deduction also reaches individual owners.
What happens if the work does not finish on time
The deduction applies to amounts paid in each tax year, but requires the work to be finished and certified within the deadline. A renovation stretching into 2027 falls outside the 20% and 40% deductions, even if part was paid in 2026.
If you are tight on dates, the priority is not paying faster but finishing and certifying before December 31. Talk to the certifying technician now: their December diary usually fills up.
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