Superbonus Italy 2026 — API Integration Guide for Developers

Italy’s Superbonus is simultaneously the most generous and the most complex renovation subsidy in Europe. Originally launched at 110% in 2020 (yes — the government paid more than the cost of the renovation), it has been gradually reduced: 90% in 2024, 70% in 2025, and now 65% in 2026. Even at 65%, it remains one of Europe’s highest subsidy rates.

But the eligibility rules are intricate. This guide explains every concept you need to integrate Superbonus calculations into your application, with API examples for different work combinations.

The Superbonus timeline

The 65% rate means that for every €100 spent on qualifying renovation, the homeowner receives €65 back as a tax deduction over 4 years (€16.25/year). This is not a cash grant — it reduces the homeowner’s tax liability. If the homeowner does not have enough tax liability to absorb the deduction, they can transfer the credit.

Driving works vs. driven works

This is the concept that confuses everyone. Superbonus uses a cascading eligibility model:

Driving works (interventi trainanti) — required

At least one driving work must be included in the project for any work to qualify for Superbonus. There are two categories:

1. Thermal insulation of the building envelope — must cover at least 25% of the gross dispersing surface area (superficie disperdente lorda). Applies to: exterior wall insulation (cappotto termico), roof insulation, floor insulation. Spending ceiling: €50,000 per single-family unit or €40,000 per unit in buildings with 2–8 units.
2. Replacement of the centralized heating system — replacing the existing boiler or heating system with a high-efficiency heat pump (minimum COP 3.0), condensing boiler (minimum Class A), or hybrid system. Spending ceiling: €30,000 per single-family unit or €20,000 per unit in condominiums with up to 8 units.

Driven works (interventi trainati) — optional, unlocked by driving works

These qualify for Superbonus only if at least one driving work is included in the same project:

• Window replacement — ceiling €60,000 per unit
• Solar panels (photovoltaic) — ceiling €48,000 or €2,400/kW
• Solar thermal — ceiling €60,000 per unit
• EV charging stations — ceiling €2,000 per unit
• Home automation systems for energy management — ceiling €15,000

The 2-class improvement requirement

Beyond including a driving work, the entire renovation must achieve a minimum 2-class improvement on the APE (Attestato di Prestazione Energetica) energy certificate. Italy uses classes A4, A3, A2, A1, B, C, D, E, F, G (where G is worst and A4 is best).

Example: a building rated F must reach at least D after renovation. If the building is already rated B, it must reach A2 — much harder to achieve.

This is verified by two APE certificates: one pre-renovation (APE ante) and one post-renovation (APE post), both prepared by a qualified tecnico abilitato. The post-renovation APE must be filed on the ENEA portal within 90 days of work completion.

The GreenCalc API uses the energy_rating field and the submitted works to estimate whether the 2-class improvement is achievable. If the combination of works is unlikely to achieve 2 classes, the API falls back to Ecobonus rates instead of Superbonus.

API example 1: Full Superbonus qualification

A single-family home rated F, with wall insulation (driving work) + heat pump (driving work) + windows (driven work). This is the ideal Superbonus scenario:

curl -X POST https://greencalc.io/api/v1/eligibility/simulate \
  -H "X-Api-Key: gc_sandbox_000000000000000000000000000000000" \
  -H "Content-Type: application/json" \
  -d '{
    "country_code": "IT",
    "household": {
      "annual_income": 45000,
      "household_size": 4,
      "is_owner": true
    },
    "property": {
      "type": "HOUSE",
      "energy_rating": "F",
      "postal_code": "00185",
      "surface_m2": 120
    },
    "planned_works": [
      {"work_type": "WALL_INSULATION_EXTERIOR", "estimated_cost_eur": 22000, "surface_m2": 100},
      {"work_type": "HEAT_PUMP_AIR_WATER", "estimated_cost_eur": 12000},
      {"work_type": "WINDOWS_DOUBLE_GLAZING", "estimated_cost_eur": 8000}
    ]
  }'

Expected response (sandbox, illustrative):

{
  "eligible_subsidies": [
    {"scheme_name": "Superbonus 65%",
     "type": "TAX_DEDUCTION",
     "amount_eur": 27300.0,
     "details": "65% of €42,000 total. Driving: insulation + heat pump. Driven: windows. 2-class improvement: F→D estimated achievable."}
  ],
  "summary": {
    "total_estimated_cost_eur": 42000.0,
    "total_grants_eur": 0.0,
    "total_loans_eur": 0.0,
    "total_tax_savings_eur": 27300.0,
    "estimated_out_of_pocket_eur": 14700.0
  }
}

Note that the Italian subsidy appears as TAX_DEDUCTION type, not GRANT. This distinction is important for UI display — the homeowner does not receive cash, they receive a reduction in their tax bill over 4 years.

API example 2: Only driven works (Ecobonus fallback)

What happens when someone submits only windows? No driving work is present, so Superbonus does not apply. The API falls back to Ecobonus:

curl -X POST https://greencalc.io/api/v1/eligibility/simulate \
  -H "X-Api-Key: gc_sandbox_000000000000000000000000000000000" \
  -H "Content-Type: application/json" \
  -d '{
    "country_code": "IT",
    "household": {
      "annual_income": 45000,
      "household_size": 2,
      "is_owner": true
    },
    "property": {
      "type": "APARTMENT",
      "energy_rating": "E",
      "postal_code": "20121",
      "surface_m2": 75
    },
    "planned_works": [
      {"work_type": "WINDOWS_DOUBLE_GLAZING", "estimated_cost_eur": 6000}
    ]
  }'

Expected response:

{
  "eligible_subsidies": [
    {"scheme_name": "Ecobonus 50%",
     "type": "TAX_DEDUCTION",
     "amount_eur": 3000.0,
     "details": "50% deduction over 10 years. Superbonus not applicable: no driving work included."}
  ],
  "summary": {
    "total_estimated_cost_eur": 6000.0,
    "total_grants_eur": 0.0,
    "total_loans_eur": 0.0,
    "total_tax_savings_eur": 3000.0,
    "estimated_out_of_pocket_eur": 3000.0
  }
}

Ecobonus for windows is 50% (not 65%) and is spread over 10 years instead of 4. The annual deduction is much lower: €300/year vs. €6,825/year for a Superbonus project of the same value. This makes a significant difference for users with limited tax liability.

API example 3: Condominium renovation

Condominiums have different spending ceilings. For a building with 6 apartments doing a comprehensive renovation:

curl -X POST https://greencalc.io/api/v1/eligibility/simulate \
  -H "X-Api-Key: gc_sandbox_000000000000000000000000000000000" \
  -H "Content-Type: application/json" \
  -d '{
    "country_code": "IT",
    "household": {
      "annual_income": 35000,
      "household_size": 3,
      "is_owner": true
    },
    "property": {
      "type": "APARTMENT",
      "energy_rating": "G",
      "postal_code": "10121",
      "surface_m2": 90
    },
    "planned_works": [
      {"work_type": "WALL_INSULATION_EXTERIOR", "estimated_cost_eur": 15000, "surface_m2": 60},
      {"work_type": "HEAT_PUMP_AIR_WATER", "estimated_cost_eur": 8000},
      {"work_type": "SOLAR_PANELS_PHOTOVOLTAIC", "estimated_cost_eur": 5000}
    ]
  }'

For condominiums, Superbonus applies to common areas (facade insulation, centralized heating) with the per-unit ceilings. Individual apartment works (windows, internal insulation) use separate ceilings. The GreenCalc API uses the property.type: "APARTMENT" flag to select condominium-appropriate ceilings.

Cessione del credito: transferring the tax credit

The cessione del credito (credit transfer) mechanism is what made Superbonus viable for low-income households who do not have enough tax liability to use the deduction themselves. In 2026, three options exist:

1. Direct deduction: Keep the credit and use it against your own IRPEF (income tax) over 4 years. Best for high-income households with stable tax liability.
2. Credit transfer to bank: Sell the credit to a bank at a discount. Banks typically pay 80–85 cents per euro. A €27,300 credit becomes €21,840–23,205 in immediate cash (minus bank fees).
3. Sconto in fattura: The contractor accepts the credit as payment and applies it to the invoice. The contractor then transfers the credit to a bank. This means the homeowner pays nothing upfront — but the contractor must be willing (many are not, due to cash flow constraints).

Spending ceilings by work type

Superbonus has per-unit spending ceilings that cap the deduction regardless of actual cost. These ceilings are coded into the GreenCalc API:

If actual costs exceed the ceiling, only the ceiling amount qualifies for the 65% deduction. Excess costs can sometimes qualify for the lower Bonus Casa (50% over 10 years).

Fallback schemes: Ecobonus and Bonus Casa

When Superbonus does not apply (no driving work, no 2-class improvement, or ceiling exceeded), Italy has two fallback schemes:

• Ecobonus (50–65%): For energy efficiency improvements that do not meet Superbonus requirements. 65% for wall insulation and heating replacement; 50% for windows and solar shading. Deduction over 10 years.
• Bonus Casa (50%): A general renovation deduction. Applies to any building renovation including non-energy works. 50% over 10 years, ceiling €96,000 per unit. This is the fallback of last resort.

The GreenCalc API automatically evaluates Superbonus first, then Ecobonus, then Bonus Casa, and returns the most favorable option for each work item. In some cases, different works in the same project may use different schemes.

Integration tips for Italian properties

• Always collect the energy rating — the 2-class improvement check is impossible without the current APE class. If the user does not know it, the API assumes a conservative estimate.
• Distinguish HOUSE from APARTMENT — spending ceilings differ significantly. An apartment in a 6-unit condominium has lower per-unit ceilings but the total project may be larger.
• Show the deduction timeline — unlike French grants that are paid once, Italian deductions are spread over 4 years (Superbonus) or 10 years (Ecobonus/Bonus Casa). Users need to understand this.
• Include the cessione del credito discount — show both the face value and the estimated cash value (multiply by 0.82 as a conservative estimate for bank purchase price).
• Monitor political changes — Italy’s subsidy landscape has changed every year since 2020. Use the GreenCalc changelog API or webhooks to stay current.

For comparison with other countries, see the EU renovation subsidies guide. For the energy efficiency comparison by work type, see our country comparison article. Full API documentation at greencalc.io/docs.

GreenCalc is built by AZMORIS Group. Italian subsidy data sourced from Agenzia delle Entrate and ENEA publications. Always verify with your commercialista or tecnico abilitato before starting works.