Italian tax deductions and window bonuses 2026: what to check before work starts

Important notice. The rates, caps and requirements of Italian tax deduction schemes change frequently and depend on the annual Budget Law, its implementing decrees and the circulars issued by the Italian Revenue Agency (Agenzia delle Entrate). This article lists the main schemes available in 2026 but does not quote specific percentages, because they may already have been updated by the time you read it. Always check current rates through official channels before signing any contract, and speak to your accountant before basing a major spending decision on a tax incentive.

I’ve worked in the window and door industry for twelve years, and one of the phrases I hear most often at the first site visit is “there’s a bonus for this anyway”. Sometimes that’s true, sometimes it’s only partly true, and sometimes it doesn’t apply to the specific case at all. The problem isn’t that Italian bonus schemes don’t work — the problem is that their scope changes every year, and the gap between “I’m entitled to the bonus” and “I’m entitled to the bonus with no procedural errors” is enormous. To avoid ending up at the end of the job with a rejected application, it pays to understand the structure before signing the quote.

1. General overview: the four schemes relevant to window replacement

Within Italy’s 2026 tax system there are — under names, scopes and procedures that change over time — four main families of incentives relevant to window replacement. I list them in logical order, without percentages, because rates must be checked through official channels at the time of the expenditure.

Ecobonus for energy efficiency

This is historically the most relevant deduction for anyone replacing windows, because it rewards exactly the outcome achieved by replacing old windows with high-performance ones: reducing the overall thermal transmittance of the building envelope. The eligible intervention is the replacement of existing windows bordering the heated volume towards the outside or towards unheated spaces — so replacement, not a new installation on a previously blind wall, and only on properties already fitted with a heating system. Rates, caps and combinability with other schemes must be checked on the official ENEA page at https://www.enea.it/.

Bonus Ristrutturazioni (renovation bonus)

This is the deduction for extraordinary maintenance, restoration, conservative refurbishment and building renovation works. Window replacement falls under it when configured as extraordinary maintenance or included within a broader renovation project. The logic differs from the Ecobonus: it doesn’t reward the energy performance of the new window, it rewards the building intervention itself. The reference authority is the Agenzia delle Entrate, https://www.agenziaentrate.gov.it/.

First-home and main-residence bonus

For properties used as a main residence, some incentives carry increased percentages or higher caps. Here too the parameters vary and the current version of the scheme must be checked. A common mistake is assuming a property qualifies as a “first home” for bonus purposes simply because it does for land-registry purposes: the two definitions don’t always coincide.

Invoice discount and tax-credit transfer

The invoice discount (“sconto in fattura”) is the mechanism whereby the supplier applies a discount directly on the invoice equal to the deduction owed, and then recovers the tax credit itself. Tax-credit transfer (“cessione del credito”), on the other hand, allows the client to “sell” their credit to banks, the post office or financial intermediaries, monetising the incentive immediately. These mechanisms have undergone significant restrictions in recent years, to the point of near-total closure for many types of intervention. Whether they can be used in the current tax year must always be verified with your accountant before basing any financial planning on them.

2. Minimum technical requirements of the window: Uw transmittance by climate zone

To access the Ecobonus, the new window must meet the thermal transmittance (Uw) limit values set by Ministerial Decree of 26 June 2015, commonly known as the “Minimum Requirements Decree” (Decreto Requisiti Minimi). These values are stable legislation, not subject to the annual Budget Law, so they can be quoted without risk. The Uw value indicates how much heat the whole window (frame plus glass plus spacers) allows through per square metre and per degree of temperature difference. Lower is better.

Italy is divided into six climate zones, from A (the warmest) to F (the coldest), based on the degree-days of each municipality. The Uw limit values required by the decree are indicatively:

• Zone A (Lampedusa, Linosa): Uw ≤ 3.00 W/m²K approx.
• Zone B (Catania, Palermo, Reggio Calabria, southern Sicily): Uw ≤ 2.20 W/m²K
• Zone C (Naples, Bari, Cagliari, Cosenza): Uw ≤ 1.80 W/m²K
• Zone D (Rome, Florence, Ancona): Uw ≤ 1.60 W/m²K
• Zone E (Milan, Turin, Bologna, Padua, most of northern Italy): Uw ≤ 1.40 W/m²K
• Zone F (Belluno, Cuneo, Alpine valleys): Uw ≤ 1.30 W/m²K

Check the ENEA page for the updated value for your zone, as revisions to the decree can slightly change these limits. The quote must clearly state the Uw for every window type offered, calculated according to standard UNI EN 14351-1 and supported by the manufacturer’s technical data sheet or certification report. To understand how to read these values and choose the right configuration for your zone, read our guide to Uw transmittance and climate zones. An “approximate” or “estimated” Uw on the quote isn’t enough: the ENEA application requires the exact value.

In concrete terms: a customer in Bologna (zone E) installing a window with Uw 1.50 has material that meets commercial requirements but not the bonus requirements, and loses the deduction. To stay on the safe side, it’s worth going comfortably below the limit — Uw 1.2 in zone E, Uw 1.1 in zone F — rather than working right at the minimum. All the Salamander GreenEvolution 76, BlueEvolution 72 and BlueEvolution 82 profiles we manufacture comfortably meet the requirements for zones E and F with appropriate glazing.

3. The ENEA application: timing, documents, form

The ENEA application is the administrative step many customers discover only at the end of the job. It is a mandatory online communication required to access the Ecobonus, to be submitted within 90 days of the completion date of the works. If this deadline is missed, the bonus is lost, and there is no late-remedy procedure that can fix it.

Submission is exclusively online through the portal https://detrazionifiscali.enea.it/ (the portal is periodically renewed, so check the updated address on the main ENEA site). You need to register an account and complete the application, entering the beneficiary’s personal details, the property’s land-registry details, the type of intervention, costs broken down between windows, building works and professional services, and the technical data of the windows installed together with their transmittance values.

The documents needed to complete the application are:

• Technical data sheet of the installed window (Uw, Ug, dimensions, CE marking)
• Supplier’s invoice with a breakdown of costs
• Sworn technical statement from a qualified professional (required in some cases)
• Land-registry details of the property
• Tax code of the person claiming the deduction

Once the application is submitted, ENEA issues a confirmation code (CPID) which must be kept. That code is proof the application exists, and should be filed together with the rest of the tax documentation for the following ten years.

A detail many people underestimate: the completion date is the date the work is actually finished, not the invoice date. If the invoice is dated 15 March but installation finishes on 30 April, the 90 days start from 30 April. It’s still advisable to submit the application within 30-45 days of actual completion, to avoid problems with holidays or any errors that need correcting.

4. The “bonifico parlante” (labelled bank transfer): the correct payment reference

The “bonifico parlante” is the mandatory payment method for tax deductions on property. It’s called “speaking” (parlante) because the payment reference must “speak” — that is, it must cite the relevant legislation. An ordinary bank transfer, even if executed correctly in every other respect, is not valid for bonus purposes, and no subsequent correction can remedy the error. This is one of the most frequent and painful mistakes.

The correct payment reference must contain four elements:

1. Legal reference: “Bonifico per detrazione ai sensi dell’art. 16-bis del DPR 917/86” for the Bonus Ristrutturazioni, or “Bonifico per detrazione ai sensi dell’art. 1, comma 344-349, Legge 296/2006” for the Ecobonus, or the wording currently in force.
2. Tax code of the beneficiary of the deduction (the person who will pay less tax). This doesn’t always match the person who physically makes the transfer.
3. VAT number or tax code of the supplier (the company carrying out the installation).
4. Invoice number and date the payment refers to.

The main Italian banks offer a dedicated “bonifico per detrazioni fiscali” form already pre-filled with the correct structure. It’s always worth using it rather than writing the reference by hand. If you realise you’ve made an ordinary transfer by mistake, speak to your accountant immediately: in some cases it can be remedied with a substitute declaration, but this is uncertain ground and depends on the tax year involved.

Amounts: the transfer must be made for the full invoice amount, not just the deductible share. Any deposits must also be paid via a bonifico parlante referring to the same invoice, or to separate deposit invoices, each with its own bonifico parlante.

5. Energy Performance Certificate (APE) before and after the work

The Energy Performance Certificate (Attestato di Prestazione Energetica, APE) is the document certifying a property’s energy class. For window replacement carried out as a stand-alone intervention it isn’t always mandatory, but where it is required it must be produced both before the works (to document the starting condition) and after (to document the improvement). In other cases, a sworn statement from a qualified professional confirming compliance with the minimum requirements is sufficient, without a full APE.

It is drawn up by a qualified energy certifier (typically a surveyor, technical expert or engineer registered on the relevant regional list). Indicative cost: €200-500, depending on the area, the complexity of the property and the professional involved. For an 80-100 m² flat in a medium-to-large city, you’re generally looking at around €300 plus contribution fund charges and VAT.

The APE is valid for ten years, unless works are carried out that change the energy performance — which window replacement does. So even if you have a recent APE, it must still be redone after the works if it’s needed for the application.

It’s worth asking the certifier to also provide a digitally signed PDF copy: it’s needed for the ENEA application and for the documentation you must keep. Filing with the regional energy register is the certifier’s own responsibility, but always ask for confirmation of the reference number.

6. Invoice discount and tax-credit transfer: recent history

Between 2020 and 2023, the invoice discount and tax-credit transfer mechanisms expanded enormously, largely on the back of the Superbonus 110%. Progressive restrictions then followed, gradually reducing the ability to apply these two mechanisms to most interventions. Today the situation is highly fragmented: for some types of work and some client profiles, transfer remains possible; for many others it doesn’t.

What this means in practice: don’t base your investment on the expectation of “monetising the credit immediately” without first checking with your accountant that the mechanism is still active for your case. I’ve seen jobs start with the promise of a “50% invoice discount” that then couldn’t be applied, leaving the client having to cover the full cost while waiting to recover the deduction over ten years of tax returns.

Where the invoice discount is still applicable, the supplier needs to be structured to manage it: the ability to advance the credit, relationships with institutions that purchase it, and proper accounting for building-related tax credits. Not every company in the sector is set up for this, and that’s legitimate — but ask before signing the contract, not after.

7. Full documentation to keep

For the ten years following the deduction, the following documents must be carefully retained, in original form where required. The Agenzia delle Entrate can request them at any time during an audit.

1. Invoices from the supplier, with a full breakdown of the interventions and cost allocation (windows, ancillary building works, labour, professional services).
2. Bonifico parlante transfers, kept as bank copies showing all data and the full payment reference.
3. Technical data sheets for every window installed, with Uw, Ug, Psi (spacer) values, Rw acoustic performance, air permeability class, water tightness and wind-load resistance.
4. CE markings for the windows, with the Declaration of Performance (DoP) under EU Regulation 305/2011.
5. APE before and after the works, where applicable, with the regional reference number and the certifier’s digital signature.
6. Sworn statement from a qualified professional, where required by legislation for the type of intervention.
7. ENEA submission receipt with the CPID code.
8. Communications to the municipality, if the works required a CILA or other building permit.
9. Title deed to the property, or an up-to-date land-registry extract, proving ownership.
10. Payment receipts for professional services (certifier, technical expert, surveyor if involved).

Everything should be organised in a single folder, ideally both paper and digital, and kept readily accessible for your accountant at tax-return time and in the following years.

8. Common mistakes that cause the bonus to be lost

These are the mistakes I’ve seen recur most often over the years, and they all result in the loss of the entitlement to the bonus. Almost all of them are avoidable with a bit of care upfront.

• Paying by means other than the bonifico parlante: cheques, cash, ordinary bank transfers, credit cards, or financing without the correct coordination. This is the most frequent mistake.
• Generic or incomplete payment reference on the bonifico parlante. Missing legal reference, missing beneficiary’s tax code, missing invoice number.
• Failure to submit the ENEA application within 90 days of the completion date.
• Window with non-compliant Uw for the climate zone limit. This often happens when material is chosen purely on price, without checking the technical data sheet.
• Installer without a valid DURC certificate (regularity of social security contributions) or without the required professional qualifications. Check in advance.
• Wrong beneficiary: the transfer was made by a spouse who isn’t a co-owner of the property, or the tax code stated is that of the person paying but not the person claiming the deduction.
• Bundled invoice combining windows, furniture, internal doors and other works without distinction. It must be itemised, because each line item carries a different bonus (or none at all).
• Deposits not paid with the correct labelled reference. Deposits must also follow the bonifico parlante rule.
• Works started before the required communication, where one is mandatory (for example a CILA in some contexts).
• Incomplete technical documentation, in particular a data sheet without a certified Uw value or without CE marking.

9. Realistic timelines for the bonus process

It’s worth having a sense of the order of magnitude of the timeline. From the moment you decide to replace your windows to the moment the deduction starts appearing on your tax return, more time passes than most people expect.

• Site visit and quote: 1-3 weeks, including a detailed survey if needed.
• APE before the works, if needed: 1-2 weeks.
• Contract signature, deposit, factory order: on standard Salamander PVC jobs, 4-6 weeks from order to delivery.
• Installation: usually 1-3 days on site for an average flat.
• APE after the works and technical sworn statement, if needed: 1-3 weeks after completion.
• ENEA submission: within 90 days of completion, but best done within the first 4-6 weeks.
• Tax return and first instalment of the deduction: the tax year following the year of the expenditure.
• Full recovery of the deduction: ten equal annual instalments (standard structure, subject to change).

Overall, from the initial quote to the first recovery on your tax return, you’re typically looking at 8-14 months. For the full amount to be recovered, it’s ten years from the first instalment. Important to know if you were counting on a faster payback to finance other works.

10. What LMT provides customers to make the process easier

On this point, the difference between a well-organised supplier and an improvised one is enormous. A customer who reaches the end of the works with incomplete documentation loses time, money and sometimes the bonus itself. Our standard practice is to hand the client, at the end of the job, a complete documentation folder containing:

• Full technical data sheet for every window installed, with Uw, Ug, Psi, Rw values, permeability classes, wind and water performance.
• CE marking and Declaration of Performance (DoP) for every profile and configuration.
• Site photos before, during and after installation, useful as evidence in the event of an audit.
• Itemised invoice with separate line items for windows, installation, any ancillary works, any disposal charges.
• Instructions for the bonifico parlante with a pre-filled payment reference ready to copy at the bank, together with up-to-date tax code and VAT number.
• Reference to the technical standard applied to installation (UNI 11673:2017) for quality documentation.
• Pre-filled technical data useful for the ENEA application, ready to enter into the portal.

The client’s own accountant remains the point of reference for choosing the bonus best suited to the specific case, calculating the actual deduction, and filing the tax return. We don’t replace tax advice — we complement it from the technical side.

11. Frequently asked questions

Can I use the Ecobonus if I replace windows in a second home? Yes, the Ecobonus isn’t limited to a main residence. Conditions should be checked through official ENEA channels, as some items are treated differently.

Do I always have to get an APE before the works? Not always. For window replacement alone, in many cases a sworn statement from a qualified professional confirming compliance with the minimum requirements is enough. A full APE becomes necessary for broader interventions or for specific property categories.

If I only replace some windows and not all of them, am I still entitled to the bonus? Yes, the bonus also applies to partial interventions. Each replaced window is assessed individually for compliance with the Uw value required for its climate zone.

Does the residents’ assembly need to approve replacing my windows? For a “like-for-like” replacement within your own unit, no assembly approval is needed, although the building’s regulations may impose aesthetic constraints (colour, panel layout). For works on common parts, or for significant changes to the façade, yes, it must be approved at the assembly.

Can I pay the supplier in cash if the amount is small? No, never, if you want to access the tax deductions. The bonifico parlante is a condition of access regardless of the amount.

What happens if ENEA rejects my application? ENEA notifies the applicant of the error, with the option to correct it, provided you’re still within 90 days of completion. If the 90 days have expired, the bonus is generally lost.

Can I combine the Ecobonus and the Bonus Ristrutturazioni on the same window? No, for the same intervention you need to choose one. The choice depends on which has the higher rate in your case and which combines better with any other planned works.

How far in advance of the works do I need to decide which bonus I’ll use? Before signing the contract. The contract terms, the invoice, the bank transfer and the subsequent application will all be set up differently depending on the scheme chosen.

If I sell the property before finishing the ten instalments of the deduction, do I lose them? No, generally they continue in favour of the buyer, unless otherwise agreed in the sale deed. This must be communicated to the notary at the time of completion.

If the property is jointly owned, who claims the deduction? The person who incurred the expense, documented by the bonifico parlante made out in their name, claims the deduction. It can also be split between joint owners, but transfers and invoices need to be coordinated consistently.

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Want a quote that already factors in materials compatible with your climate zone’s bonus? Contact us and tell us your city in the form. Our quote sheet includes the Uw values required for your corresponding zone, so you know straight away that the material offered already complies with the bonus requirements.