Tax Deduction for Energy Efficiency Works in Homes 2026

# Tax Deduction for Energy Efficiency Works in Homes 2026

The tax deduction for energy efficiency works in homes allows recovering between 20% and 60% of the amounts invested in energy improvements, directly from the full IRPF tax liability. In 2026, this deduction — regulated in the additional provision number 50 of Law 35/2006 of the IRPF, modified by Royal Decree-Law 19/2021 — remains valid and is one of the most relevant for property owners undertaking rehabilitation. The exact amount you can deduct depends on the type of work, the improvement accredited in the energy efficiency certificate, and whether you act individually or through a homeowners' association.

Which Works Entitle You to the Energy Efficiency Deduction in 2026

Not all renovation works generate the right to deduction. The regulation requires that the actions produce a verified and quantified improvement in the energy efficiency of the property, demonstrated by the energy efficiency certificate issued by a competent technician before and after the works (according to AEAT and Royal Decree 390/2021 that regulates the certification procedure).

Eligible actions are grouped into three main categories:

• Reduction of heating and cooling demand: insulation of facades, roofs, floors, and windows (replacement of windows with double or triple glazing, installation of blinds with thermal bridge break, etc.).
• Improvement of the energy performance of installations: replacement of gas boilers with air-source heat pump or heat pump systems, installation of ventilation systems with heat recovery, improvement of the thermal envelope.
• Integral energy rehabilitation of the building: when the action affects the entire building and is processed through the homeowners' association, with a significant reduction in the consumption of non-renewable primary energy.

Important: The mere replacement of appliances, painting facades without insulation improvement, or installing LED lighting does not grant the right to this deduction, although they may reduce electricity consumption.

The Three Deduction Tranches: 20%, 4, and 60%

The tax deduction for energy efficiency works in homes is structured in three modalities with different percentages and maximum bases (according to the additional provision number 50 of the IRPF Law, in the wording valid in 2026):

Tramo del 20%: Reduction of Heating and Cooling Demand

• Deduction Percentage: 20% of the amounts paid.
• Requirement: that the works reduce by at least a 7% the combined demand for heating and cooling, or a 7% reduction in heating or cooling alone, as accredited by the energy efficiency certificate.
• Maximum Deduction Base: 5,000 € per year (according to the regulation valid in 2026; check the updated wording in AEAT or the BOE).
• Maximum Annual Deduction: up to 1,000 €.
• Eligible Homes: residential property or any property in rental or in expectation of rental.

Tramo del 40%: Improvement of Consumption of Non-Renewable Primary Energy

• Deduction Percentage: 40% of the amounts paid.
• Requirement: that the works reduce by at least a 30% the indicator of consumption of non-renewable primary energy of the energy efficiency certificate, or that the home improves its energy rating to obtain a class A or B.
• Maximum Deduction Base: 7,500 € per year (according to the regulation valid in 2026; verify in AEAT).
• Maximum Annual Deduction: up to 3,000 €.
• Eligible Homes: the same as in the previous tranch.

Tramo del 60%: Energy Rehabilitation of Buildings

• Deduction Percentage: 60% of the amounts paid.
• Requirement: that the works are carried out on the entire building (not just the individual home) and that the consumption of non-renewable primary energy is reduced by at least a 30%, or that the building improves its energy rating to class A or B.
• Maximum Deduction Base: 5,000 € per year per owner, with a maximum accumulated total of 15,000 € in the years the deduction applies (according to the regulation valid in 2026; consult the BOE and AEAT for the exact wording).
• Maximum Annual Deduction: up to 3,000 €.
• Who Can Apply It: owners of homes in buildings predominantly used for residential purposes who participate in energy rehabilitation works of the entire building, usually channeled through the homeowners' association.

Common Requirements for the Three Tranches

Regardless of the applicable percentage, the tax deduction for energy efficiency works requires meeting a series of conditions (AEAT, Law 35/2006):

1. Previous and Posterior Energy Efficiency Certificate: issued by a competent technician and registered in the corresponding autonomous body. Without this document, the deduction is not applicable.
2. Payment via Traceable Bank Means: transfer, card, direct debit. Cash payments do not grant the deduction.
3. Invoice from the Installation Company or Contractor: with a breakdown of materials and labor. The company must be registered in the corresponding IAE category.
4. The Works Must Not Be Linked to Economic Activities: if the property is partially used for business or professional activity, only the portion destined for residential use generates the right to deduction.
5. Application Period: amounts not deductible due to insufficient tax liability can be carried forward to the four following years (check the exact period in the regulation valid in 2026 with AEAT).

Practical Examples of Calculation

Example 1: Window Replacement with 7% Improvement in Demand (20% Tranch)

María is the owner of an apartment in Madrid. In 2026, she installs double-glazed windows with thermal bridge break for a total of 4,800 € (including VAT). The energy efficiency certificate after the works certifies a 9% reduction in the combined demand for heating and cooling.

• Deduction Base: 4,800 € (below the 5,000 € limit).
• Deduction Applicable: 4,800 € × 20% = 960 € to deduct from the full IRPF tax liability.
• If María's full tax liability is 3,200 €, she will pay 2,240 € after the deduction.

Example 2: Installation of Air Source Heat Pump with 35% Improvement in Energy Consumption (40% Tranch)

Carlos replaces his gas boiler with an air source heat pump in his residential home in Zaragoza. The total cost is 9,000 €. The certificate after the works certifies a 35% reduction in the consumption of non-renewable primary energy.

• Maximum applicable base in 2026: 7,500 € (the excess of 1,500 € does not generate deduction in this year).
• Deduction Applicable: 7,500 € × 40% = 3,000 € to deduct from the full tax liability.
• The remaining 1,500 € can be applied in subsequent years if the regulation allows (consult AEAT or a tax advisor).

Example 3: Building Rehabilitation Through the Homeowners' Association (60% Tranch)

A homeowners' association in Barcelona undertakes the energy rehabilitation of the building. The total cost is 120,000 €, distributed among 20 owners. Ana's share is 6,000 €.

• Maximum annual base: 5,000 € (the excess of 1,000 € is carried forward to the next year, up to the accumulated limit of 15,000 €).
• Deduction Applicable in 2026: 5,000 € × 60% = 3,000 €.
• The remaining 1,000 € will generate an additional deduction of 600 € in the following year.

Compatibility with Subsidies and Other Aids

One of the most common errors is applying the deduction on the gross amount of the work when a public subsidy (IDAE, Recovery Plan, regional aids) has been received. The regulation establishes that the deduction base must be reduced by the amount of subsidies received that are exempt from IRPF or have not been taxed as income (according to AEAT and Law 35/2006).

For example: if the work costs 10,000 € and you received a subsidy of 3,000 €, the deduction base will be 7,000 €, not 10,000 €. Applying the deduction on the gross amount is one of the most common reasons for AEAT regularization.

This deduction is compatible with the autonomous deductions that some communities establish for energy improvement works, provided they do not fall on the same taxable base. Consult the specific deductions of your community in the AEAT's electronic portal or in your regional administration's portal.

How to Apply the Deduction in the 2026 Income Tax Return

The deduction for energy efficiency works is recorded in the specific boxes of the deduction section of the full tax liability in the model 100 (IRPF return). For the 2026 exercise, the specific boxes will be available in the draft tax return that AEAT publishes in the 2027 campaign.

Documentation you must keep and have ready:

• Previous energy efficiency certificate (with original rating).
• Posterior energy efficiency certificate (with the accredited improvement), registered in the corresponding autonomous body.
• Invoices from the installation company with full breakdown.
• Bank payment justifications (transfers, card statements).
• In the case of the 60% tranch: certificate from the homeowners' association with the amount corresponding to each owner.

If you have doubts about which boxes to fill or how to calculate the base, use the AEAT's help tool or consult a tax advisor before submitting the return.

Errors to Avoid with the Energy Efficiency Works Deduction

AEAT has intensified the review of these deductions in recent years. The most common errors that lead to requests or complementary settlements are:

• Not having the previous certificate: if you don't have the energy efficiency certificate before the works, you cannot prove the improvement and the deduction is not applicable.
• Applying the deduction on the non-deductible VAT: the VAT supported in residential property works is part of the deduction base (unlike in economic activities).
• Confusing the state deduction with the autonomous ones: they are compatible but have different bases and percentages. Do not sum them in the same box.
• Not registering the posterior certificate: the posterior energy efficiency certificate must be registered in the competent autonomous body to be valid for the deduction.
• Deducting works in ineligible properties: only residential properties (not commercial premises, independent garages, or storage rooms) are eligible.