Amount of the deduction and incompatibilities with the remaining deductions for energy efficiency improvement works
A. Basis of deduction
For the 2021 financial year, the base of this deduction will be constituted by the amounts paid, box  of the declaration , by credit or debit card, bank transfer, nominative check or deposit into accounts in credit institutions , to the people or entities that carry out such works, as well as to the people or entities that issue the aforementioned certificates.
However, those amounts that, where applicable, would have been subsidized through a public aid program or would be subsidized by virtue of a final resolution of the granting of such aid, will be deducted.
Note: In no case will amounts paid through deliveries of legal tender money give the right to deduct.
For these purposes, amounts paid for the works carried out will be considered those necessary for their execution, including professional fees, costs of drafting technical projects, construction management, cost of execution of works or installations, investment in equipment and materials and others. expenses necessary for its development, as well as the issuance of the corresponding energy efficiency certificates.
Note: In any case, not these amounts will be considered the costs related to the installation or replacement of equipment that uses fuels of fossil origin.
In the case of homes of a community nature, the amounts paid from the community property for a marriage under a legal community property regime will be attributed to each spouse at 50 per 100 .
Works carried out by a Community of owners
In this case, the aforementioned means of payment (credit or debit cards, bank transfer, nominative check or deposit into accounts in credit institutions) must be used by the community of owners when satisfying the works to the people or entities that carry out the works. themselves.
This deduction for improvement works is applied to the amounts paid, without the regulations governing it establishing special rules for cases in which external financing is used.
The amount capable of forming the basis of the deduction of each taxpayer will be determined by the result of applying to the amounts paid by the community of owners, the participation coefficient that they have in it.
If the invoice identifies the community of owners as the final recipient, the taxpayer may justify the investment and expense made through the receipts issued by the community in which payment of the amounts proportionally corresponding to them is required, the supporting documents of payment thereof, supporting documents for the works carried out and other means of proof admitted by law.
B. Maximum deduction base
The maximum annual base per declaration of this deduction will be 5,000 euros per year .
C. Excess over the maximum deduction base, transfer to the following four years and maximum accumulated deduction base
The amounts paid not deducted (bases pending deduction) for exceeding the maximum annual deduction base may be deducted, with the same limit, in the following four years, without in any case the accumulated base of the deduction exceeding 15,000 euros (multi-year maximum limit).
D. Deduction percentage
The percentage of deduction applicable on the deduction base, in the terms previously discussed, is 60 per 100 .
This deduction will be incompatible with the deductions “ For improvement works that reduce the demand for heating and cooling ” and “ For improvement works that reduce primary energy consumption. renewable ” in those cases in which the accredited improvement and the amounts paid correspond to actions carried out in the building as a whole.