Measuring the energy consumption of a building

The energy consumed by the buildings, to operate or for the use of the residents, is from different sources: electricity, gas or hot water. In an energy transition approach, the main challenge is to reduce energy consumption. This necessarily involves measuring the energy consumption of buildings accurately. What regulations govern energy consumption in buildings in France? How can the energy consumption of a building be measured?

The legal framework for the consumption of buildings

It is estimated that the energy consumption of buildings (offices, single-family homes and apartment buildings) accounts for 45% of the total energy consumed (Ministry of the Environment – 2017).

Despite a noted improvement in energy efficiency in the industrial sector in 2017, the efforts to be performed remain significant. The State has therefore implemented a legal framework to encourage the reduction of energy consumption by companies.

It is composed of two laws that determine the level to be reached to assess whether or not the energy consumption of buildings is in line with an energy transition logic: Article 17 of the Energy Transition Law and the elan law.

Article 17 of the Energy Transition Law is one of the pillars of the regulations surrounding the energy performance of buildings. It is the first legislation of this scope to include the obligation to renovate buildings from 2020 to 2050.  During this 30-year period, the expected level of decrease in energy consumption of buildings is to be reassessed.

Passed in 2018, the Elan law provides a framework for reducing energy consumption in the tertiary sector. This should be 40% in 2030, compared with 2010. The decrease in energy consumption of buildings should reach 60% in 2050, again taking the energy expenditure of the year 2010 as a reference value.

consommation énergétique des bâtiments

How to measure the energy consumption of a building?

Measuring energy consumption is the first step in any approach to reducing or limiting consumption. The first measurement you will perform is the one that will serve as a reference value, in order to set up an energy saving plan that can be implemented over the next few years.

This first step generally takes the form of a study called an energy audit, mandatory energy audit for companies with more than 250 employees or a turnover of more than 50 million euros.

Performing an energy audit

The energy audit can be performed in two distinct cases. In the first case, you are subject to an obligation to perform a certified energy audit. In the second case, you are not concerned by any obligation but wish to perform an assessment of your consumption, which is also recommended.

The certified energy audit can be the starting point for an EMS (Energy Management System) approach, or it can be implemented to meet the obligation of large companies. In this case, it will have to be renewed every 4 years. The only exception to the rule: companies with ISO 50001 certification are exempt from audit renewal.

In this case, it is a question of performing a so-called “decisional” energy audit. In this case, a professional is in charge of taking thermal measurements of your building and collecting all the necessary information to create an energy optimization plan adapted to your objectives.

Increasingly, the traditional energy audit can be replaced by local or remote solutions, such as the installation of connected sensors in the home. You can then consult the results of the audit directly online, via a dedicated application.

The business energy audit performed remotely is particularly suitable for non-compulsory companies. Your service provider can then draw up an inventory of your energy performance based on key data on your professional consumption and energy use. You will then have a set of recommendations that you will be free to transform into action, for example by making a transition to renewable energies.

Monitor the energy consumption of your buildings in real time

As the audit is a first step in defining a baseline, it is essential to continue measuring the energy consumption of buildings over the long term. Connected sensors (IoT), which are increasingly accurate, allow the consumption of buildings to be monitored continuously. This has several advantages:

First of all, you can quickly identify energy leaks and abnormally high consumption, in order to react over time. Second, having a view over a few weeks or even months of your main energy expenditure items will help you see more clearly and implement the actions needed to reduce your next bill.

How to access this data? Quite simply, via a platform, accessible from your smartphone. You then have an overview of your consumption in real time. A good starting point to consider an energy optimization plan without any work.