Italian Energy Class (APE) Explained: What a G Really Means for Heating, Price and the EU's Green Homes Rules

By Patrick · 2026-10-22

The energy class on an Italian listing comes from the APE, the energy performance certificate, and ranges from A4 (best) to G (worst). A G does not mean a fixed number of kilowatt-hours: it means the house uses far more energy than a new-build version of the same house in the same place. Read the index and the estimated consumption on the certificate, not just the letter.

It is worth reading closely. Of the residential certificates issued in Italy in 2024, 24.2% were class G, the largest single class, and F and G together made up 45.3%, according to the national energy agency ENEA's 2025 report on energy certification. These are certificates issued that year, mostly for sales and lettings, not a census of Italian homes, but they show what a buyer meets on the market.

What the APE measures

The APE (attestato di prestazione energetica) is required by Legislative Decree 192/2005. It is issued by an independent qualified expert, who must visit the building at least once, and it is valid for up to ten years, provided the heating system's periodic checks are done. Work that changes the energy class means a new certificate.

The class is based on one index, EPgl,nren: the non-renewable primary energy the building needs in a year under standard use, per square metre of floor area, for heating, hot water, cooling and ventilation. It is a calculated figure for a standard household, not a meter reading and not what the current owner pays.

Page 2 of the certificate is the most useful part for a buyer. It lists the energy sources the house uses and the estimated annual consumption of each under standard use, for example cubic metres of gas or kWh of electricity, plus the improvement works the certifier recommends.

Why the letter alone misleads

The Italian scale is relative. The certifier first calculates a reference building: the same house, with the same shape, orientation and location, but built to today's minimum standards. Its index is the boundary between A1 and B, and every other class is a multiple of it. According to the national guidelines of 2015 (DM 26/06/2015):

• Class C: 1.2 to 1.5 times the reference
• Class D: 1.5 to 2 times
• Class E: 2 to 2.6 times
• Class F: 2.6 to 3.5 times
• Class G: more than 3.5 times

So a G in a cold Alpine comune and a G on the Sicilian coast can mean very different amounts of energy, and two C houses can differ a lot in kWh per square metre. That is why the law also requires the index itself in every listing, and why it is worth comparing the number, not the letter.

Two more points. A house without any heating system does not automatically get a G: the certifier simulates a standard gas system and rates the house with it. And certificates are not always right. ENEA's checks found anomalous values in almost half of the certificates it examined. If an old, unrenovated house shows a surprisingly good class, ask for a second opinion.

What it means for heating costs

There is no official figure for how much more a G costs to heat than a C, because the class depends on each building. The best estimate is on the certificate itself: take the estimated annual consumption on page 2 and multiply it by today's price.

To show the order of magnitude, here is an illustration for a 100 m² house heated with a gas boiler. We convert the index to gas with the primary energy factor for natural gas (1.05) and ARERA's conversion of 10.70 kWh per cubic metre, then price it at the regulator's reference for September 2026 of €1.6202 per cubic metre, taxes included (ARERA):

• A house whose APE shows 300 kWh/m²: about 2,670 m³ of gas, roughly €4,330 a year
• A house whose APE shows 100 kWh/m²: about 890 m³, roughly €1,440 a year

This is arithmetic, not a forecast. Which classes those two numbers fall into depends on the reference building. Standard use assumes the whole house heated through the entire legal heating season, which many households, and most holiday homes, do not do. The regulator's price is a benchmark for protected customers, not your contract. Electricity prices have risen too: see our article on Italy's electricity price rise of October 2026.

What it means for the price

The most thorough Italian study is by the Bank of Italy: Questioni di Economia e Finanza no. 818 (2023), on about 15.9 million Immobiliare.it listings from 2018 to 2022. Comparing otherwise similar homes in the same neighbourhood, it found:

• class A homes listed about 25% higher than class G
• class C homes about 16% higher than class G
• a premium for class A of 12–16% in mild climate zones, rising to 33% and 37% in the two coldest zones

These are asking prices, not sale prices, and the authors warn that energy classes are not fully comparable across regions. But the direction is clear: the market already discounts poor classes, most of all where winters are long.

What the seller must do

Italian law puts the duty on the seller:

• From the start. The listing must state the energy class and the index; whoever publishes an ad without them can be fined €500 to €3,000.
• During negotiations. The seller must make the APE available and hand it over at the end.
• In the deed. The deed contains a clause confirming you received it, with a copy annexed. If the clause or copy is missing, the parties can be fined €3,000 to €18,000; the sale itself remains valid.

Some buildings are exempt, notably a ruin or a shell sold "al rustico", if the deed says so. Then there is no energy data at all, and you need a technician to estimate the work. An ad that says "classe energetica in fase di richiesta" (energy class being requested) means there is no certificate yet.

The EU's "case green" directive: what it does and does not do

The recast Energy Performance of Buildings Directive, (EU) 2024/1275, is often reported as a ban on selling inefficient homes. It is not. For homes it sets a national average: the energy use of the whole residential stock must fall by at least 16% by 2030 and by 20–22% by 2035 compared with 2020, with at least 55% of that coming from renovating the worst-performing 43% of homes. Fixed minimum standards for individual buildings apply only to non-residential buildings. The directive contains no rule that stops a home from being sold or rented because of its class.

Two things to watch. Each country chooses how to reach its target and may introduce its own measures for homes. And the certificate itself will change: the directive requires a new A–G scale on which A means a zero-emission building, so Italy's current ten-class scale will have to be redrawn and today's C will not automatically be tomorrow's C. As of October 2026 Italy has not yet transposed the directive, and the European Commission has started proceedings over its missing draft renovation plan, so no new national obligation applies to private homeowners yet.

Upgrading: the tax relief in 2026

Energy works qualify for Italy's renovation relief: in 2026, 36% of the spending for a house that is not your main home, or 50% for an owner's registered main residence, falling to 30% and 36% in 2027 unless the law changes. The Superbonus ended on 31 December 2025. The relief is a deduction from Italian income tax over ten years, not a grant, so it only helps if you pay income tax in Italy.

Before you make an offer

• Ask for the APE itself at the first contact, not just the class on the listing.
• Check its date, and ask for the boiler logbook (libretto di impianto) to confirm the checks were done.
• Read the index and page 2's estimated consumption, then compare them with twelve months of real bills.
• Ask your geometra or a termotecnico (heating engineer) to check the certificate's inputs, and to price the recommended works.
• Ask the notaio or geometra to confirm the APE is registered in the regional energy register.

Where Trovara fits

The Trovara Individual Property Report (€109) reads the energy class declared on the listing, estimates what the house costs to heat and run each year, and puts that next to the renovation estimate and the all-in budget, so a cheap class G casale (country house) and a dearer class C house can be compared on what they cost to own. You can see the format in our sample report. Confirm the class against the certificate itself.

Prepared with AI assistance and reviewed by the Trovara team. This article is general information, not technical, tax or legal advice. Sources: D.Lgs. 192/2005 and DM 26/06/2015; ENEA–CTI report on energy certification (2025); Bank of Italy QEF no. 818 (2023); Directive (EU) 2024/1275; ARERA gas reference price for September 2026. Checked in October 2026. Always verify with a geometra, a termotecnico or a notaio before you sign.