Which works require it
The obligation does not concern every renovation but only works with an energy content. The check is made against the type of operation.
It covers works claiming the ecobonus, for which transmission is required as a matter of course, and certain categories of renovation deduction works producing energy savings or involving renewable sources. The renovation deduction categories concerned should be checked case by case.
Works with no energy content fall outside the obligation and, as a rule, so do seismic works, which follow their own documentary regime. On mixed works the check is made operation by operation.
On system replacement the check should be made together with the exclusion of fossil fuel boilers: the systems still eligible, such as heat pumps, hybrid systems, biomass generators and heat pump water heaters, carry the notification obligation. The two checks are made together rather than in sequence.
The ordinary deadline
The general rule is that the descriptive form must be transmitted within ninety days of completion of the works or, where provided, of final inspection. The deadline is strict and cannot be extended on request.
Two useful points on the calculation.
The deadline runs from the completion date declared in the file, which makes fixing and documenting that date a necessary step rather than a formality. An uncertain date makes the deadline itself uncertain.
If the ninetieth day falls on a Saturday, Sunday or public holiday, the deadline moves to the next working day. The rule also applies to the municipality's local holidays.
The three starting rules of 2026
An event in 2026 introduced particular rules that remain relevant for works in that year, and are worth knowing because they depart from the ordinary deadline. It was the suspension of the portal.
The portal was suspended from 4 February to 24 June 2026 while it was adapted to two instruments: the 2026 legislative decree transposing the EU renewable energy directive, in force from 4 February, and the new decree on minimum building requirements, which revised the methods for calculating and verifying energy performance. The two instruments changed the methods of calculation.
By a notice of 25 June 2026 the body brought the update into operation and clarified the starting date in three situations. The three situations differ by the completion date of the works.
| Situation | Start of the ninety day period |
|---|---|
| Works started from 4 February 2026 and completed before 25 June 2026 | From 25 June 2026, the date the update was published |
| Works started before 4 February 2026 | Ordinary rule, from the declared completion date |
| Works completed from 25 June 2026 onwards | Ordinary rule, from the declared completion date |
The rationale for the first situation is explicit: the period during which the system was unavailable must not affect compliance with deadlines by taxpayers and the professionals instructed, and entails no loss of the tax benefit. The suspension therefore produces no forfeiture.
For a professional who ran sites completed in the spring of 2026, this is the rule that saves the files left frozen. The completion date is worth documenting in order to rely on it.
The content of the form
The descriptive form gathers the technical data of the works, and its content varies with the deduction claimed. The content should be checked against the current guidance notes.
For the ecobonus the technical data must be entered both for the new system or element and for the pre existing one being replaced. On building services works this means having the data of the equipment removed, which must be recorded before removal rather than reconstructed afterwards.
For heating systems the performance parameters of the equipment installed are also required, under the indicators the technical rules impose for the type. The parameters are read from the product data sheet.
The operational consequence concerns site procedure: the data of the system being replaced must be recorded and photographed at the point of removal, because it is the only element of the form that becomes irrecoverable once the equipment is gone. The record must be made before removal rather than after.
Access and transmission
Access to the portal uses the digital identities provided for public administration services. The credentials should be checked before the deadline falls.
For professionals handling a significant volume of files there are authorised channels allowing centralised transmission, including for works on the common parts of buildings. Authorisation should be requested in advance rather than at the first deadline.
One practical point: at peak periods the portal can slow down, and filing on the last available day is a risky choice on a formality whose omission has tax consequences. It is worth transmitting as soon as the data are complete.
The late filing remedy
This is the most valuable information on this page, because it turns an apparently final omission into a recoverable position. It is the remissione in bonis remedy.
Where transmission is missed, the remissione in bonis remedy allows the omission to be cured by sending the notification and paying a set penalty, within the deadline for the first available tax return. The remedy must be used within a precise deadline.
The penalty is 250 euros and is paid using the unified payment form quoting the relevant tax code. Payment precedes or accompanies the filing of the notification.
The remedy has a precise time limit, however, and is not indefinitely available: it must be used before filing the return for the year in which the works were completed. Once that deadline passes the omission becomes final.
For a professional discovering an omission, the first check therefore concerns where the position sits relative to that deadline. The check is made against the year in which the works were completed.
The most frequent errors
Treating the notification as a formality following the closing of the site is the first, and places it outside the project checklist. The step belongs on the closing checklist alongside final inspection.
Not fixing and documenting the completion date is the second, and leaves uncertain the start of a strict deadline. The date should be recorded in the building application file.
Removing the system being replaced without recording its data is the third, and makes part of the form impossible to complete. The data cannot be reconstructed after removal.
Filing on the last available day is the fourth, and on a portal subject to slowdowns is an avoidable risk. A portal slowdown on the last day costs the deadline.
Treating the omission as irremediable is the fifth, and leads to giving up a benefit the late filing remedy would preserve. The remedy is available up to the first return that can carry it.
Note: the information in this page relates to Italy and is current as at the date of publication. The body publishes notices amending operating rules and deadlines: the notices in force at the date of consultation should be checked before any operational use.