Electricity coefficient in the EPC: what the shift from 1.9 to 1.7 will change in 2027

From 1 January 2027, the way the EPC is calculated will change for homes that use electricity: the electricity coefficient, also known as the conversion factor from electricity to primary energy, will drop from 1.9 to 1.7. In practical terms, this means that the same electricity consumption will weigh less heavily in the primary energy consumption shown on the certificate.

For an owner, a buyer or an estate agent, the question is simple: can this reform improve a home's EPC rating? In some cases, yes. Service-Public.fr states that this reduction is intended to lower the primary energy consumption calculated for electrically heated homes and that it may lead to an improved energy label.

Be careful, though: this change does not automatically turn every electric home into a top performer. The EPC remains an overall assessment of the property: insulation, floor area, ventilation, domestic hot water production, heating, joinery, greenhouse gas emissions and the 3CL method all continue to count.

What is the electricity coefficient in the EPC?

The EPC does not simply look at the energy you consume at the meter. It converts that consumption into primary energy, that is, the energy taken into account to produce, transport and deliver the energy used in the home.

For electricity, this conversion is done using a coefficient. With a coefficient of 1.9, 1 kWh of final electricity counts as 1.9 kWh of primary energy in the calculation. With a coefficient of 1.7, the same kWh will count as 1.7 kWh of primary energy.

The difference may look small, but it matters: going from 1.9 to 1.7 reduces the weight of electricity in the "primary energy" part of the calculation by roughly 10.5 %. For example, 10,000 kWh of final electricity represented 19,000 kWh of primary energy with a coefficient of 1.9; it will represent 17,000 kWh with a coefficient of 1.7.

What changes on 1 January 2027

The reform announced by Service-Public.fr rests on one central point: lowering the electricity conversion factor from 1.9 to 1.7. This will change three main things:

• EPCs carried out from 1 January 2027 will automatically apply the new coefficient. You will not have to ask the assessor for it: the calculation method will directly take the new value into account.
• Electrically heated homes may see their calculated primary energy consumption fall. The more electricity weighs in the home's uses (heating, hot water, sometimes cooling), the more visible the potential effect can be.
• Some homes may gain an energy class, if the calculated drop in consumption is enough to cross a rating threshold.

On the other hand, the reform does not change the home's actual consumption. Your bill does not fall because the coefficient changes. What evolves is the regulatory translation of that consumption in the EPC calculation. This is in fact the second step, after a first change to the electricity coefficient in 2026.

Which homes are affected?

The homes most concerned are those whose energy uses rely heavily on electricity:

• houses or flats heated with electric radiators;
• homes fitted with a heat pump;
• properties where domestic hot water is produced by an electric tank;
• homes combining electric heating, electric hot water and little use of other energy sources.

The potential gain will nevertheless depend on the exact profile of the home. A very well insulated flat with an efficient heat pump will not react like an old house heated with electric convectors. Likewise, a home whose poor rating comes mainly from insulation, heat loss or another energy item will not necessarily change letter.

That is why you should avoid quick promises such as "all electric homes will gain a class". The reform can help, but the final result depends on the complete EPC calculation.

Will my home necessarily gain an EPC class?

No. The shift from 1.9 to 1.7 can improve the calculated primary energy consumption, but it does not guarantee a change of class.

A home may stay in the same letter if:

• it is far from the upper threshold of its current class;
• its heat losses remain too high;
• its final rating is limited by other parameters;
• the climate label or the dual-threshold logic prevents a visible improvement;
• electric heating does not represent a large enough share of the calculation.

Conversely, a home close to a threshold may see a real change. For example, a property currently rated F but very close to class E could potentially move up if the new conversion reduces the calculated primary energy consumption enough. This point should be checked against the data of the existing EPC or during a new assessment.

A simple example: why lowering the coefficient can matter

Imagine a home where a significant part of the standard consumption is electric. With the old coefficient of 1.9, 15,000 kWh of final electricity represents 28,500 kWh of primary energy. With the new coefficient of 1.7, it represents 25,500 kWh of primary energy.

In this simplified example, the primary energy consumption taken into account therefore falls by 3,000 kWh. That is not enough to predict the new EPC class, but it shows why the reform can move certain homes.

The benefit is especially strong for properties that already sit near a threshold. For a selling owner, it can change how the property is perceived. For a landlord, it can also influence the analysis of rental constraints linked to energy-inefficient homes. For a buyer, it can change the way a recent or older EPC is interpreted.

What should you do if you already have an EPC?

EPCs carried out before 2027 do not automatically become invalid because of this reform. Service-Public.fr indicates that EPCs carried out before the rules come into force remain valid, but that they may be updated free of charge, without a new visit from the assessor, if the energy label improves.

The ministry, for its part, reminds us that an EPC is in principle valid for 10 years, with exceptions for older assessments carried out before the July 2021 reform. EPCs carried out since 1 July 2021 are valid for 10 years.

In practice, from 1 January 2027, the right reflex will therefore be to:

• find the number of your EPC;
• check its validity;
• look at whether a certificate or update is available through the EPC Observatory;
• have a new EPC carried out only if the home's situation has changed, if the assessment is no longer valid, or if you need an up-to-date document to sell, let or decide on works.

The ministry specifies that assessors send EPCs to the ADEME Observatory, which issues a 13-digit identification number; without this number, the EPC is not valid.

Selling owners: what impact on value and negotiation?

For sellers, the main issue is how buyers read the property. A better EPC label can make a listing more attractive, reduce reluctance to visit and limit some negotiations linked to energy works.

It does not replace genuine thermal performance. A serious buyer will always look at the detail of the EPC: insulation, heating system, summer comfort, recommended works, estimated costs and overall consistency. But a change of class can alter the first impression, particularly for properties currently penalised by electric heating.

If your home is electrically heated and you are considering a sale in 2027, it will be useful to check whether an EPC update is possible before listing. The EPC is a central benchmark in the property market: it directly influences a property's value and its ability to be let over time.

Landlords: watch the timetable for energy-inefficient homes

For landlords, the stakes can be even more concrete. Homes rated G, F and then E are progressively affected by rental restrictions or obligations to anticipate. An improvement in class can therefore change the asset strategy: immediate works, arbitrage, re-letting, step-by-step renovation or sale.

Lowering the electricity coefficient can help some properties climb out of a critical class, but it must not be used as an excuse to postpone all renovation. If the home remains uncomfortable, energy-hungry or poorly insulated, the reform will not fix the underlying problem.

The right reasoning is to separate two subjects:

• the regulatory rating, which can change with the calculation method;
• the real quality of the home, which depends on works, insulation, ventilation and equipment.

Buyers: how to interpret an EPC before or after 2027?

For a buyer, this reform raises an important question: was the EPC presented calculated before or after the coefficient change?

An EPC carried out in 2026 and an EPC carried out in 2027 will not treat electricity in exactly the same way. This does not make the older assessment useless, but it calls for nuance, especially for electrically heated homes.

Before negotiating, it can be worthwhile to:

• check the date of the EPC;
• ask for the assessment's ADEME number;
• look at whether the home is close to a threshold;
• distinguish between method flaws and genuine defects in the building fabric;
• ask an assessor for advice if the EPC rating determines your buying decision.

This reading is particularly important for investors, first-time buyers and estate agents who support transactions on homes rated E, F or G.

Estate agents: how to explain the reform to your clients?

For an estate agent, the message must stay simple: the electricity coefficient is falling, some EPCs may improve, but each home must be checked individually.

In a valuation, a mandate or a negotiation, two mistakes must be avoided: announcing an automatic improvement, or on the contrary ignoring the reform for electric homes. The right approach is educational: explaining that the calculation is changing, that the impact depends on the property's characteristics, and that an official update should be preferred where possible.

This reform can also be an opportunity to reconnect with owners of electric homes rated E, F or G, especially those who had given up selling or letting because of a penalising rating.

Do you need to redo an EPC in 2027?

Not necessarily. If your EPC is still valid and a free update is enough, there is no need to redo an assessment straight away.

On the other hand, a new EPC can be relevant if:

• you have carried out works since the last assessment;
• the EPC is old or no longer valid;
• you are preparing a sale or a rental;
• you need a clear document to reassure a buyer, a tenant or an agency;
• the home is close to an important regulatory threshold.

For a reliable assessment, it is advisable to prepare your EPC properly before the visit. RITMO Diagnostic offers EPC assessments and energy audits, with branches notably in Caen, Angers, Le Havre, Morlaix, Saint-Lô, Strasbourg, Vierzon and Vire.

What this reform does not change

Lowering the electricity coefficient does not change everything. It does not automatically alter:

• the state of the insulation;
• winter or summer comfort;
• the actual consumption paid by the occupant;
• ventilation defects;
• the need to deal with thermal bridges;
• the relevant recommended works.

In other words, a better calculation does not replace a better home. The EPC remains a decision-support tool, not a renovation in itself.

Conclusion: good news for some electric homes, but not an automatic verdict

The shift of the electricity coefficient from 1.9 to 1.7 on 1 January 2027 should ease the weight of electricity in the EPC calculation and may improve the label of some electrically heated homes.

To find out what it really changes for your house or flat, you need to check your EPC, its date, its ADEME number, the home's characteristics and how close it is to the class thresholds.

Are you an owner, a buyer or a property professional? RITMO Diagnostic can help you read your EPC, understand the impact of the reform and decide whether you need an update, a new assessment or an energy audit. You can also browse our articles on the EPC to go further.

FAQ

Is the EPC electricity coefficient really going from 1.9 to 1.7?

Yes. Service-Public.fr states that the order of 19 August 2026 lowers the electricity conversion factor from 1.9 to 1.7, effective on 1 January 2027.

Will all electric homes gain an EPC class?

No. Some homes may improve their label, but it is not automatic. The impact depends on the share of electricity in the calculation, insulation, equipment, ventilation and how close the home is to the class thresholds.

Does my old EPC remain valid?

Yes, if its period of validity has not expired. EPCs carried out since 1 July 2021 are valid for 10 years, unless the home changes significantly or you need to redo an assessment for a property transaction.

Will I have to pay to update my EPC?

Service-Public.fr indicates that a free update, without a new visit from the assessor, may be possible when the new coefficient improves the energy label.

Will the change of coefficient lower my electricity bill?

No. The change concerns the regulatory EPC calculation. It changes neither your actual consumption, nor the price of electricity, nor the physical performance of the home.

Are heat pumps affected?

Yes, if the home uses an electric heat pump, the new coefficient can change the weight of that consumption in the calculation. The real impact will nevertheless depend on the equipment's efficiency and the home's other characteristics.