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Energy efficiency: definition, challenges and levers for action
Reading 12 min
April 15, 2025
Summary
Energy efficiency means using less energy to deliver the same service, without compromising comfort or performance. It plays a key role in the ecological transition by reducing greenhouse gas emissions, energy dependency, and costs.
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INDEX
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What is energy efficiency?
Definition of energy efficiency
Energy efficiency refers to the ability to perform the same action or deliver the same service while using less energy. It is not about doing without, but rather about optimizing the use of energy resources through efficient equipment, smart technologies, or improved practices.
In practical terms, energy efficiency can mean heating a building while using less electricity, manufacturing an industrial product with reduced energy loss, or using more fuel-efficient vehicles. Energy efficiency applies to all sectors: buildings, industry, transportation, and digital technology.
It is a major lever for reducing greenhouse gas emissions, lowering energy costs, and preserving natural resources. As such, energy efficiency is part of a long-term performance approach, central to ecological and energy transition strategies.
Energy management vs. energy efficiency: what’s the difference?
Energy management is a broad concept that encompasses all actions aimed at reducing energy consumption, whether through improved technical performance or changes in behavior. It is based on two key pillars: energy efficiency and energy sobriety.
Energy efficiency means doing more with less—that is, delivering the same service (heating, lighting, production, etc.) while using less energy thanks to more efficient equipment or technologies.
Energy sobriety, on the other hand, involves voluntarily reducing usage by questioning its necessity. For example, lowering the heating temperature in a home or choosing to cycle instead of drive.
Thus, energy efficiency is one component of energy management, while the latter also includes lifestyle and behavioral choices. Both approaches are complementary and essential for a successful energy transition.
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Why is energy efficiency crucial?
Environmental challenges
Energy efficiency plays a central role in the fight against climate change. By reducing the amount of energy needed to produce, heat, move, or light, it directly lowers greenhouse gas emissions, particularly those linked to the combustion of fossil fuels (coal, gas, oil).
This lever is all the more essential given that the energy sector alone accounts for nearly three-quarters of global CO₂ emissions. Improving energy efficiency means acting at the source—reducing energy needs before even considering offsetting or decarbonizing production.
Beyond climate concerns, gains in energy efficiency help preserve natural resources, which are often limited or environmentally damaging to extract (such as coal or uranium). It also reduces local pollution, such as fine particulate emissions from heating systems or combustion engines.
Finally, energy efficiency is key to achieving the European Union’s carbon neutrality goals by 2050. Combined with greener energy production, energy efficiency is one of the pillars of a successful ecological transition—sober, sustainable, and resilient.
Economic challenges
Energy efficiency is also a strategic economic lever for individuals, businesses, and local authorities. By lowering energy consumption, it helps reduce bills and improve the long-term profitability of investments.
For households, energy efficiency translates into direct savings, particularly on heating, electricity, and fuel expenses. At the business level, better energy efficiency can lead to greater competitiveness by reducing production costs while enhancing environmental performance.
It is also a value-adding factor for property: a well-insulated building or one equipped with an efficient heating system will be more attractive on the market. Many financial incentives and subsidies support such initiatives, making investments more accessible.
Moreover, the energy efficiency sector is a driver of economic growth, generating jobs in construction, energy services, consulting, and technological innovation.
Thus, improving energy efficiency helps lower expenses, anticipate energy price increases, and position oneself in a more sustainable economy.
Strategic and geopolitical challenges
Energy efficiency also has significant strategic and geopolitical dimensions. By reducing dependence on imported energy—especially hydrocarbons—countries strengthen their energy sovereignty and their ability to withstand international crises.
Geopolitical tensions, such as fluctuations in oil markets, have highlighted the vulnerability of economies that heavily rely on energy imports. By consuming less, countries limit their exposure to price hikes, supply disruptions, and economic shocks.
Energy efficiency also helps reduce trade imbalances related to massive imports of gas, oil, or coal. It fosters economic stability and national security by lowering risks associated with energy markets.
Finally, on the international stage, countries that commit to ambitious energy efficiency policies can assert their climate leadership while driving technological innovation. It is also a way to accelerate the energy transition without having to wait for a complete transformation of the energy mix.
Thus, improving energy efficiency is not just an ecological or economic issue—it is also a key lever for geopolitical resilience.
It plays a key role in the ecological transition, by reducing greenhouse gas emissions, energy dependence and costs.
How to improve energy efficiency?
In buildings (residential, commercial, public)
Buildings are one of the most important sectors for achieving energy savings, whether in residential, commercial, or public settings. In France, they account for nearly 45% of final energy consumption, making the improvement of building energy efficiency a top priority.
There are many levers for action in this sector. One of the most effective is thermal insulation—of walls, roofs, windows, and floors. Good insulation significantly reduces heat loss in winter and excessive energy use in summer. Replacing outdated heating systems with more efficient equipment (such as heat pumps or condensing boilers) is another key strategy.
Smart energy management through connected thermostats, motion sensors, or centralized control systems can further optimize energy use without compromising comfort. Installing LED lighting, which consumes less electricity, can complement these measures.
In the commercial and public sectors, energy performance initiatives are often framed by regulations, such as France’s “decret tertiaire.” The goal is twofold: reducing operating costs and meeting climate obligations. Thus, improving energy efficiency in buildings is a cornerstone of the ecological transition.
In businesses and industry
Improving energy efficiency in companies and industry is a strategic lever for performance, innovation, and competitiveness. Industry is one of the most energy-intensive sectors, particularly in production, heating, cooling, and machine operation.
The first step is often to carry out an energy audit, which helps identify the most energy-consuming areas and prioritize actions. Then, targeted solutions can be implemented: equipment upgrades, waste heat recovery, process automation, or optimization of electric motors. Smart energy management systems can adapt consumption to actual needs and quickly detect issues.
Companies can also highlight their efforts through certifications (such as ISO 50001 or ISO 14001) and integrate these initiatives into their CSR strategies. Beyond meeting regulatory requirements, these actions help sustainably lower operating costs while improving environmental performance.
In transportation
The transportation sector is a major contributor to greenhouse gas emissions, mainly due to its reliance on fossil fuels. Improving energy efficiency in this area effectively reduces carbon footprints while lowering fuel-related costs.
Several actions can be taken. For vehicles, upgrading fleets to more efficient models (hybrids, electric vehicles, CNG-powered) helps reduce energy consumption per kilometer. Regular maintenance, proper tire inflation, and eco-driving techniques also improve energy performance.
Logistics optimization is crucial for businesses: consolidating deliveries, avoiding empty trips, and smart route planning help reduce travel distances and energy use.
On the individual level, increasing the use of public transportation, cycling, or walking contributes to more efficient mobility. Promoting carpooling or remote work also helps reduce energy-intensive travel.
Through digital technology
Digital solutions also play an increasingly important role in improving energy efficiency. Smart technologies enable better understanding, control, and optimization of energy consumption across all sectors.
In buildings, building management systems automatically regulate heating, lighting, and ventilation based on real needs, thus reducing waste. In industry, connected sensors and monitoring software make it easier to track equipment energy performance in real time.
Data analysis tools help identify consumption anomalies and anticipate future needs, while also facilitating decision-making. In transport, digital solutions help optimize routes, consolidate trips, and improve traffic flow.
However, digital use must also be approached responsibly. Digital sobriety, combined with an optimized infrastructure, helps ensure that efficiency gains are not offset by the energy consumption of the technologies themselves. In this way, digital technology becomes an accelerator of energy performance, as long as it is used intelligently and efficiently.
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How to calculate energy efficiency?
Basic principles
Calculating energy efficiency means measuring the amount of useful energy obtained in relation to the total energy consumed. The goal is to determine whether an action (heating, producing, lighting, etc.) uses energy optimally or not.
The basic formula is:
Energy efficiency = Useful energy / Total energy consumed
💡For example, a high-efficiency boiler that consumes 100 units of energy and delivers 90 units of heat has an energy efficiency of 90%. The closer this ratio is to 1 (or 100%), the more efficient the equipment is.
This approach allows for evaluating the efficiency of a device, a building, or an industrial process, and for comparing different solutions. Calculations can be made at various scales: a single device, a production line, an entire building, or even a whole organization.
Calculating energy efficiency is essential for identifying improvement opportunities, assessing the return on investment of a measure, or tracking progress in an energy transition process. It forms the foundation of any energy optimization strategy.
Indicators and measurement tools
To assess and monitor energy efficiency, several key indicators are used depending on the sector and the objectives. Among the most common are:
kWh/m²/year: used in the building sector, measures energy consumption per square meter per year.
Energy Performance Index (EPI): allows comparison of the performance of a dwelling or equipment.
Energy efficiency (%): expressed as a percentage, reflects the ratio between useful and consumed energy.
Specific consumption (kWh/product): in industry, measures the energy needed to produce one unit.
Energy labels (A to G): used for household appliances and buildings to indicate energy performance.
To measure these indicators, various tools can be used: smart meters, energy management software, energy audits, or platforms like D-Carbonize, which collect and analyze consumption data to visualize the most energy-intensive areas.
These indicators not only diagnose current performance but also help set improvement targets, prioritize investments, and track energy use trends over time.
Energy efficiency: What does the legislation say?
In France
In France, legislation on energy efficiency has been progressively strengthened, driven by energy transition and carbon neutrality goals. Today, several regulations govern the responsibilities of individuals, companies, and public authorities.
In the building sector, the RE2020 environmental regulation sets strict standards for energy performance in new constructions. For commercial buildings, the “decret tertiaire” requires owners and operators to reduce their energy consumption by 40% by 2030, 50% by 2040, and 60% by 2050 compared to a reference year.
Industrial companies may be required to conduct an energy audit every four years (as per a European directive transposed into French law), unless they operate a certified energy management system (ISO 50001).
France also offers various support schemes to boost energy efficiency: Energy Savings Certificates (CEE), MaPrimeRénov’, ADEME grants, and regional or local subsidies.
These measures are part of the Energy-Climate Law, which defines the national roadmap for an ambitious energy transition. Energy efficiency is considered a key pillar in reducing greenhouse gas emissions.
In Belgium
In Belgium, energy efficiency legislation is implemented at federal, regional, and local levels, with responsibilities shared between the three Regions (Wallonia, Flanders, Brussels-Capital). Each region has its own regulations and incentive programs.
In Wallonia, the PEB (Building Energy Performance) regulation sets strict standards for new constructions and major renovations. The Air-Climate-Energy Plan also defines ambitious targets to reduce energy use by 2030. Energy grants are available to individuals and businesses.
In Flanders, the Energiepact outlines clear goals for improving energy efficiency in the residential, commercial, and industrial sectors. The EPC label is mandatory for buildings being sold or rented.
In Brussels, the Renolution strategy aims to speed up building energy renovations through stricter regulations and substantial financial support (Renolution grants). At the federal level, Belgium applies EU directives (like the EED – Energy Efficiency Directive) and supports ISO 50001 certification in the industrial sector.
What are the benefits of energy efficiency?
Improving energy efficiency offers numerous benefits—environmental, economic, and strategic. It’s a win-win approach for individuals, businesses, and local authorities.
- From an environmental perspective, energy efficiency significantly reduces greenhouse gas emissions by lowering the energy needed for the same services. It contributes to fighting climate change and preserving natural resources.
- From an economic standpoint, it allows for long-term reduction in energy bills. A well-insulated building, efficient equipment, or optimized industrial process consumes less and costs less to operate. This improves investment profitability over time.
- Energy efficiency is also a competitive advantage for companies, helping them cut operating costs while enhancing their environmental credentials (through CSR or certifications). It also improves resilience to fluctuating energy prices.
- Finally, it helps ensure compliance with regulations, improves user comfort (thermal, acoustic), and increases property value. Energy efficiency is therefore a strategic approach that combines performance, sustainability, and frugality.
How does D-Carbonize support organizations in their energy efficiency journey?
D-Carbonize supports companies, local authorities, and institutions in measuring, managing, and optimizing their energy consumption, with a focus on sustainable performance. Its intuitive, comprehensive platform helps integrate energy efficiency at the core of an organization’s environmental strategy.
The first step involves a detailed analysis of energy consumption: the platform collects and centralizes data (electricity, gas, fuel, etc.) to visualize the most energy-intensive areas. It identifies performance gaps, anomalies, or overconsumption, allowing targeted prioritization.
D-Carbonize then provides custom action plans: equipment upgrades, process automation, reduction of energy losses, system modernization… Each action includes tracking indicators to measure the gains achieved.
The tool also facilitates energy and climate reporting, which is essential for CSR efforts, regulatory compliance, or ISO 50001 certification. It allows users to monitor performance trends, showcase results, and strengthen internal engagement.
Finally, D-Carbonize offers tailored support, adapted to the needs of each organization, regardless of its sector or environmental maturity. By using D-Carbonize, organizations can effectively reduce their carbon footprint, control energy costs, and engage in a measurable, sustainable energy transition.
