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🇮🇹 Solar Calculator Italy

Enter your monthly electricity bill and city — get solar system size, Detrazione 50% tax deduction, Scambio sul Posto credit, regional production (Nord/Centro/Sud), and payback period.

Your electricity details
€EUR
Solar system results — Italy (Nord)
3 kWp system — 1022 kWh/kWp/yr
Monthly kWh usage320 kWh/mo
Annual solar production3066 kWh/yr
Self-consumption savings€268/yr
Scambio sul Posto credit€199/yr
Total annual benefit€468/yr
System cost estimate€3300 – €4500
Detrazione 50% total value€1950 (10yr)
Detrazione per year€195/yr for 10 years
Effective cost after Detrazione€1950
Payback period4.2 years
Typical for Nord7–10 anni
25-year net savings€9739
Detrazione 50% (Bonus Casa): Claim 50% of your solar installation cost as an IRPEF tax deduction over 10 years (€195/year). Applies to residential buildings. Keep all invoices and communicate installation to your comune. Available until current Legge di Bilancio — confirm current validity.
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How to Use This Calculator

Select your city and region

Italy's solar resource varies dramatically from North to South. Palermo and Cagliari (5.2–5.3 PSH) receive roughly 50% more solar radiation than Milano (3.5 PSH). Select your city from the Nord/Centro/Sud regional groups. The calculator adjusts production estimates accordingly — a 6kWp system in Palermo produces approximately 1,500 more kWh per year than the same system in Milano.

Choose system size and net metering type

Select system size in kWp based on your roof area and electricity needs. Choose your net metering arrangement: Scambio sul Posto (SSP) is Italy's traditional net metering mechanism providing credit for exported electricity applied against imports — typically best for residential users. Ritiro Dedicato pays a fixed GSE rate for all exported energy, generally better for businesses or when export is high.

Apply Detrazione 50%

Italy's Detrazione 50% (Bonus Casa) allows you to deduct 50% of the solar installation cost from your IRPEF income tax over 10 equal annual installments. This is a tax deduction — not a grant — so you must have sufficient IRPEF liability to benefit fully. For a €6,000 system, this represents €300/year in tax savings for 10 years.

The Formula

Monthly kWh = Monthly Bill ÷ €0.25/kWh (blended retail rate) Annual production = kWp × PSH × 365 × 0.80 efficiency Self-consumption = Annual kWh × 35% Self-consumption savings = Self-consumed kWh × €0.25/kWh retail SSP credit = Exported kWh × €0.10/kWh (Scambio sul Posto) Ritiro Dedicato = Exported kWh × €0.06/kWh (fixed GSE rate) Detrazione 50% = System cost × 50% spread over 10 years Effective cost = System cost - Detrazione total value Payback = Effective cost ÷ Annual benefit

Italy's 80% system efficiency accounts for inverter losses, cable losses, soiling, and temperature derating. Northern Italy's colder winters can temporarily reduce output, while summer temperatures in the South cause temperature derating. The 35% self-consumption assumption is typical for Italian residential patterns — daytime workers have lower daytime self-consumption; retirees or home-based workers can achieve 50-60%. Scambio sul Posto (SSP) is administered by GSE (Gestore dei Servizi Energetici) and requires a specific contract agreement.

Example

Marco — Roma home, 6kWp, Detrazione 50%, Scambio sul Posto

Marco pays €130/month in Roma. He installs a 6kWp system using Scambio sul Posto and claims the Detrazione 50%.

Monthly bill€130
City / PSHRoma, 4.5 PSH
System size6 kWp
Detrazione 50%Yes
Net meteringScambio sul Posto

Result

Annual production~7,884 kWh/yr
Production per kWp~1,314 kWh/kWp/yr
Self-consumption savings~€690/yr
SSP credit income~€513/yr
Total annual benefit~€1,203/yr
System cost~€7,800
Detrazione 50% value~€3,900 (10 yr)
Effective cost~€3,900
Payback~3.2 years (effective)

The Detrazione 50% dramatically reduces effective payback in Italy. Without it, payback would be 6.5 years — still excellent for Roma. With the deduction, effective payback is 3–4 years. Sicilian and Campanian homeowners with higher PSH see even shorter payback periods (5–7 years without Detrazione; 2.5–3.5 years with it).

FAQ

Yes, especially in Southern and Central Italy. Italy has some of Europe's best solar resources: Palermo averages 5.2 PSH, producing over 1,500 kWh per kWp annually. Combined with Italy's electricity prices of €0.22–0.30/kWh and the Detrazione 50% tax deduction, residential payback periods of 3–8 years are achievable. Even northern Italy (Milano, Torino) sees 7–10 year paybacks — still financially attractive over a 25-year system life. Italy has over 1.3 million residential solar installations.
Italy's Detrazione 50% (Bonus Casa or Ristrutturazione) allows homeowners to deduct 50% of solar installation costs from their IRPEF income tax, spread over 10 equal annual installments. For a €10,000 system, this is €500/year for 10 years (€5,000 total). Requirements: (1) Residential building only. (2) Payment must be via bonifico parlante (special bank transfer). (3) Keep all invoices and communicate the intervention to your Agenzia delle Entrate. The base rate under current law (confirm with a fiscal advisor for current Legge di Bilancio provisions).
Scambio sul Posto (SSP) is Italy's net metering mechanism managed by GSE. It works on a virtual exchange: electricity you export to the grid during the day creates a credit that offsets electricity you import at other times. The compensation rate (~€0.10/kWh) is lower than the retail rate (€0.22–0.30/kWh), making self-consumption always more valuable than export. SSP is available for residential systems up to 500kW. The mechanism allows annual settlement — excess credits can roll over one year but are forfeited if unused.
Ritiro Dedicato is an alternative to Scambio sul Posto where GSE (Gestore dei Servizi Energetici) purchases all your exported solar electricity at an administratively set price (~€0.06–0.09/kWh for small systems). Unlike SSP which provides a virtual credit, Ritiro Dedicato pays cash for exports. It is generally less favorable than SSP for residential users but can be better for commercial installations with high export ratios. Some installers configure systems for Ritiro Dedicato when SSP paperwork is complex.
Italy's solar irradiance varies dramatically from north to south — more than any other major European country. Palermo (5.2 PSH) and Cagliari (5.3 PSH) in the South produce approximately 1,500–1,700 kWh per kWp annually. Roma (4.5 PSH) produces 1,250–1,350 kWh/kWp. Milano (3.5 PSH) produces only 950–1,050 kWh/kWp — about 40% less than Palermo. This massive variance means a Sicilian homeowner's 5kWp system produces the same energy as a 7kWp system in Milano.

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