Buyers: why is it wise to require an energy audit before purchasing a property?

The energy audit, an essential tool for assessing the energy performance of a property

First of all, what is an energy audit? It is a property diagnostic that provides an overall view of the energy performance and the environmental performance of a home (individual house or building). It differs from an EPC (energy performance certificate) because it goes further.

The audit is the responsibility of the seller and will be given to future buyers during the first viewing. As a buyer, this audit will help guide you regarding the work to be anticipated within the building in order to improve its thermal comfort and to enhance other ecological and energy aspects of the home or building.

It is worth knowing that buildings described as “energy sieves”, rated F or G by the energy performance certificate (EPC), are required to provide an energy audit when they are put up for sale.

Buildings rated E are also concerned since 1 January 2025, and the law provides in particular for this obligation to be extended to buildings rated D from 1 January 2034. These measures are part of the Climat et Resilience law, which aims to improve the energy performance of homes.

In 2025, it is estimated that more than 20% of homes are affected by these regulations. As
a buyer, this energy assessment will make it possible to identify the elements causing
a waste of energy within the building.

The energy audit, provided in the form of a summary report in PDF or paper format, is valid for 5 years. It notably gives rise to a standardised summary that covers all the data collected and calculated during the energy assessment.

The auditor makes all the audit results available to successive owners throughout the period of validity and can thus provide, on request, all the information concerning the works and renovation pathway issued.

How can an audit reveal the true energy performance of a home?

An audit is a key diagnostic that allows you to understand the energy issues before buying a house. This document will be produced by an impartial professional independent of the owner.

The document is broken down into a minimum of two proposals for what are known as works pathways in order to achieve a high-performance renovation. These proposals must be adapted to the architecture and the various technical constraints of the home and must not present an exorbitant cost relative to the value of the property.

The first proposal will break down the work to be carried out into stages, thus allowing a clearer view of the priorities. And a second proposal that must be achievable in a single go.

Thanks to the energy audit, which is more comprehensive than an energy performance certificate, you will have a clear view of the work to be carried out, its costs, the financial impact on future energy bills and, of course, the energy label that will be assigned to the home following this work.

This assessment is a genuine in-depth and quantified analysis that will allow you to benefit from an overall view of the thermal functioning of the home.

To carry out the audit, several steps will be performed by the energy auditor:

• Carrying out a detailed analysis of the existing situation to identify the sources of heat loss

During this complete study of the home, the professional will be able to note the construction materials used for the walls, the roof or the floors. All the heating and/or ventilation systems will also be analysed, the various openings of the home (windows and doors) and finally the presence or absence of thermal insulation.

• Measuring the actual consumption within the home

The aim of the auditor is to base themselves on the reality of the energy performance by taking into account the existing bills and the users’ habits.

• Proposing suitable work

With this energy audit, you will be able to benefit from a genuine renovation pathway with all the work to be carried out in terms of insulation, the change of equipment (boiler, etc.) and the estimated cost for each of these stages.

• Quantifying the renovations and the savings

Beyond the renovation and works proposals, the audit will allow you to have clear visibility of the expected energy gains and the resulting financial savings.

• Providing a simulation after the improvements to the home

The audit will simulate a new energy class for the home after the work. You will thus have the mention of the target EPC class and the estimated return on investment.

An energy audit offers many advantages. Beyond being more precise than an EPC, it allows you to prioritise the renovations to be anticipated and to concretely visualise the future environmental and economic benefits of the home.

Anticipate renovations and manage your energy budget

An energy audit, for you buyers, will make it possible to know precisely the work to be anticipated, but also the potential financial aid available to you for carrying out these renovations.

By having this document, you will anticipate future expenses and you benefit from an indispensable tool for your purchase decision.

It is worth knowing that today, many banks may request an energy audit as part of an application for loans linked to energy renovation. This assessment may influence the amount, the conditions, or even the granting of the loan.

By going for the purchase of a property rated E, F or G (known as “energy sieves”) that has an energy audit, you will benefit from transparency regarding the work to be anticipated and the costs that this will entail.

This offers you, as a buyer, a better view of the possible outcomes, and an easier projection within this future home.

Do not commit with your eyes closed: require an audit with a professional

RITMODiag offers the services of many diagnosticians and auditors, able to carry out the energy audits of your individual houses and buildings. Buyers and landlords, we make sure to comply with the rules in force and to provide you with a clear and detailed report, allowing you to project yourself into the future.

Operating throughout Normandy, do not hesitate to contact us in order to arrange
an appointment as soon as possible. You can call us on 02 31 15 64 88.