How can we reduce energy consumption in buildings?

par Maxime BOURASSIN le Jul 27, 2025 4:19:19 PM

Heating accounts for a large proportion of a building's energy consumption. Domestic hot water, lighting and electrical equipment follow. In residential housing, heating can consume up to 60% of energy.

In offices and tertiary buildings, lighting and IT equipment take up more space.

Occupant behavior plays a key role. Poor temperature management or appliances switched on unnecessarily increase energy consumption. The building envelope also influences energy consumption.

Poor insulation or inefficient windows let the cold in or the heat out, increasing heating requirements.

Understanding the sources of a building's energy consumption

The main areas of consumption: heating, ventilation, lighting, hot water, equipment

A building consumes energy for several daily activities. Here are the main energy items, ranked by their impact on overall consumption, according to ADEME and Cerema:

Heating: Accounts for 66% of average energy consumption in a residential building (ADEME). It uses mainly gas and electricity.
Domestic hot water: accounts for around 12% of a typical dwelling's energy expenditure. Electric or gas-fired water heaters are the main equipment used.
Ventilation: Contributes 5-10% of total consumption, according to Cerema. Poorly maintained or regulated, it increases heat loss.
Lighting: accounts for up to 10% of electricity consumption, especially in commercial buildings. LED bulbs reduce these figures compared with conventional lamps.
Miscellaneous electrical equipment: Includes devices such as computers, household appliances and connected tools. They consume around 7% of an average household in France.

Differences between residential, commercial and industrial buildings

Residential buildings consume mainly for heating, hot water and appliances. Single-family homes often use electric boilers or radiators.

In commercial buildings, lighting, air-conditioning and office equipment are the main areas of consumption. Sites of over 1,000 m² must comply with the tertiary sector decree.

This is particularly true for specific buildings such as food superstores, where indoor temperatures are strictly controlled for health and energy reasons.

👉 Find out what standards apply to supermarkets and how this impacts their consumption.

Industrial buildings, on the other hand, use enormous amounts of energy for production, ventilation and machine operation.

A concrete example: an office in the service sector can optimize its management with a BMS to reduce energy consumption by up to 20%. In industry, replacing machines with high-performance equipment can significantly lower energy costs.

💡 Read our full report on current energy measures

Consumption analysis: use, behavior, equipment, envelope

Building use has a major influence on energy consumption levels. Residential buildings heat more in winter, while commercial premises consume more for lighting and ventilation.

Daily behavior also plays a key role. Turning off a light or reducing the heating in an unoccupied room reduces the kWh consumed. Simple eco-actions, such as using a thermostat or programming equipment, improve efficiency without major work.

The condition of the equipment and the thermal envelope remain decisive factors. Poor insulation increases energy losses and adds to your bills. Upgrading the heating system or installing high-performance windows limits these losses.

Platforms like Savee help you monitor consumption in real time. Technical management, controlled via solutions like Advizeo's Cockpit, also optimizes energy efficiency.

These areas complement each other to achieve a sustainable reduction in carbon footprint.

Improving the performance of the building envelope

Good thermal insulation reduces heat loss. Using durable materials to insulate attics, walls and floors improves comfort and saves energy.

Installing high-performance windows reduces heat loss and increases energy efficiency. Sunshades provide protection from direct sunlight while maintaining a pleasant temperature.

Careful air-tightness reduces infiltration and optimizes energy consumption. Using low-carbon panels contributes to the energy transition.

Carrying out this work extends the building's lifespan while reducing greenhouse gas emissions.

Thermal insulation: attics, walls, floors, joinery

Thermal insulation is essential to reduce heat loss in buildings. This improves energy efficiency and reduces consumption.

Insulate attics first, as 25-30% of heat escapes through the roof. Choose insulating materials such as glass wool, with thermal resistance R ≥ 6 m².K/W.
Treat exterior walls, which are responsible for around 20% of heat loss. Use expanded polystyrene or rock wool with R ≥ 3.7 m².K/W.
Protect floors to prevent up to 10% of heat loss. Install polyurethane panels or an insulating screed with R ≥ 3 m².K/W.
Install high-performance joinery to limit losses through windows and doors (15%). Opt for low-emissivity double glazing with a Uw ≤ 1.3 W/m².K.
Check for airtightness around openings and use appropriate seals to prevent cold air infiltration.
Use sustainable, environmentally-friendly materials like cellulose wadding or cork to reduce your energy footprint.
Respect RT2012 or RE2020 standards when carrying out energy renovation work to achieve high energy performance.
Measure improvements regularly with an energy performance diagnosis (DPE).

Airtightness and solar protection

Air leaks increase the energy consumption of buildings. Stray air reduces insulation and forces heating systems to run longer.

Thermal regulations require efforts to be made on airtightness to limit these losses. Materials such as waterproof membranes and vapour barriers reinforce the envelope.

These solutions reduce uncontrolled air exchange.

External solar protection reduces overheating in summer. Installing blinds or shutters optimizes interior temperature. Innovative solutions such as the Cool Roof reflect solar heat, enhancing interior comfort and effectively reducing air-conditioning requirements.

These installations can easily be integrated into a sustainable ecological action plan. They also increase the value of the building while promoting intelligent energy management.

High-performance windows and sunshades

High-performance windows reduce energy consumption. Important criteria include Uw (thermal insulation), Sw (solar factor) and TLw (light transmission).

A low Uw value indicates better insulation. Double glazing reduces heat loss, while triple glazing reduces it even further - ideal for colder regions.

Sunshades control heat and light. In summer, they limit sunlight, reducing the need for air conditioning. In winter, they maximize solar gain for natural heating.

This optimizes interior comfort and saves energy.

Optimize building systems

Replace old heating systems with high-performance ones such as heat pumps. Install presence detectors for lighting to reduce off-peak consumption.

Switch to more energy-efficient LED bulbs. Adopt dual-flow ventilation to improve indoor air quality while saving energy.

Automate with building management tools for remote control. Use Advizeo's Cockpit solution to maximize savings. Maintain your equipment regularly for optimum efficiency.

Thermostatic valves reduce hot water losses. These simple actions improve energy sobriety and reduce costs.

Heating: replace with high-performance systems

Replace old equipment with high-performance alternatives. A heat pump consumes three times less energy than conventional electric heating. A condensing gas boiler reduces primary energy consumption by up to 30%.

Wood-burning systems, such as stoves and boilers, use renewable, local energy. These solutions reduce energy consumption and CO2 emissions.

Install new burners to upgrade existing boilers. Add intelligent control to optimize energy management. This adapts heating to actual needs and time of day, reducing wastage.

These actions can result in energy savings of up to 25% per year.

Ventilation: double flow, regulation, maintenance

Double-flow ventilation reduces energy losses. It heats or cools incoming air using outgoing air. This system optimizes indoor air quality by filtering out particles and allergens.

Low-energy buildings often use this technology to save energy. Precise regulation of air flow rates improves efficiency and reduces consumption.

Regular maintenance is essential. Filters must be changed to avoid over-consumption and ensure good air quality. Annual maintenance prevents costly breakdowns.

Well-set automatic controls increase overall system performance.

Lighting: switch to LED, presence detectors, time management

Lighting accounts for a significant proportion of a building's energy consumption. Simple solutions can reduce this consumption while improving comfort.

Installing LED bulbs reduces consumption by 80% compared with conventional lamps. These products last around 25,000 hours, offering a good return on investment.
Installing presence detectors enables lights to be switched off automatically in unoccupied spaces. This is particularly effective in areas such as corridors or toilets.
Programming a time management system turns lights off when they're not being used. For example, a school can turn off the lights after 6pm to save money.
Replacing all conventional switches with connected models facilitates remote control. This helps managers to monitor and manage energy at all times.
Raising occupants' awareness also encourages the application of simple ecogestures. A gesture like switching off unused lighting makes a difference to the final bill.

These measures are particularly effective in tertiary and public buildings. They rapidly reduce energy costs with little initial investment.

Hot water: optimized production, thermostatic valves

Thermostatic valves help stabilize water temperature. They avoid wastage by adjusting the heat to the nearest degree. This reduces energy consumption, especially in the residential sector.

Installing a thermodynamic tank can further improve efficiency. These systems use energy from the air to heat water, thus reducing electricity costs.

Hot water looping limits the time you have to wait for hot water at the tap. This reduces unnecessary water loss. Solar energy is also an asset for producing energy-efficient water.

Adopting these technologies and encouraging practices such as turning off the water when soaping can greatly reduce consumption without sacrificing comfort.

Reducing consumption through use and behavior

Adopting simple eco-gestures helps reduce energy consumption. Turning off lights when leaving a room or limiting air-conditioning use reduces waste.

Training occupants and raising their awareness strengthens their commitment. Collective involvement programs encourage these actions on a daily basis.

Optimized heating and lighting management improves energy efficiency. The use of presence detectors or programmed schedules limits unnecessary consumption.

Homeowners can also integrate these practices into their ecological transition strategies to achieve sustainable objectives.

Ecogestures and raising occupant awareness

Limiting energy consumption requires simple gestures. Raising occupant awareness can make a big difference.

Turning off lights when leaving a room reduces energy waste. Putting up signs near light switches is a good reminder of this action. This can reduce lighting consumption by 10%.
Reducing heating to 19°C in winter helps to save energy. Informing people about the positive impact of this reduction motivates their commitment. Each degree less is equivalent to 7% less energy.
Closing windows when heating prevents heat loss. Placing reminders at window openings encourages this reflex. This simple action improves the efficiency of the heating system.
Using power strips with switches makes it easy to switch off all unused appliances. Showing this equipment at meetings increases user awareness.
Encouraging the use of public transport or shared vehicles reduces the overall carbon footprint. Displaying a table with these options in a common area informs and encourages their use.

Setting up commitment programs

Organizing savings competitions motivates occupants. This creates positive competition within companies and administrations. In the building sector, the emulation effect is an incentive to reduce energy consumption.

In-house campaigns such as "Défi éco-gestes" help to raise staff awareness. Creating a collective dynamic strengthens everyone's involvement.

Providing practical tools supports these initiatives. Preparing information kits, educational posters and guides simplifies action for users. Platforms like OPERAT can help track efforts on commercial buildings.

These programs encourage more eco-responsible operations and contribute to sustainable development.

User training and involvement

Training managers and occupants improves energy efficiency. Practical workshops, e-learning and webinars provide a better understanding of eco-actions.

These formats motivate users to adopt new behaviors. Energy ambassadors can guide teams through the process.

Involving users helps reduce consumption. Raising awareness of equipment usage, such as heating or lighting, limits waste. Regular training guarantees lasting results in building energy management.

Implement active energy management

Install sensors and meters to track consumption in real time. Use monitoring tools to spot energy drifts quickly. The IoT network can automate this process and optimize management.

Adopt a BMS (building management system) to control systems intelligently. Energy consumption in commercial buildings is increasing every year, which is why these solutions are so important.

Continuously analyze data to detect waste. A platform like OPERAT helps you comply with industry guidelines. Organize technical days to provide information on energy reduction.

Combine these actions with specific solutions, such as motion detectors, for low-energy buildings. These methods support the goal of carbon neutrality by 2050.

Install sensors, meters and monitoring tools

Sensors measure consumption in real time. General meters track overall consumption. Sub-metering identifies specific uses, such as heating or lighting.

These tools help control and optimize the building's energy consumption.

For a small structure, costs start at €500. For larger structures, they rise to €10,000. The use of platforms such as Savee optimizes online monitoring.

Continuous consumption analysis: detecting drifts

Installing connected meters helps to monitor consumption in real time. Tools like Deepki or Energic analyze this data. They quickly detect deviations or anomalies, such as heating left on at night.

Over-consumption of hot water can also signal a problem that needs to be resolved.

Monitoring enables you to react quickly. It prioritizes actions to avoid waste. Intelligent control via a platform like OPERAT reduces energy consumption.

This optimizes equipment and improves service uses. Regular monitoring acts as a lever to achieve a low-energy building.

Intelligent control via BMS and IoT

Building Management Systems (BMS) centralize and control a building's equipment. It enables heating, ventilation, lighting and hot water to be managed remotely.

With the IoT, sensors collect and send data in real time. These tools detect consumption drifts and optimize performance.

Functionalities include the creation of scenarios (e.g. automatic lowering of heating at night), alerts in the event of anomalies or remote control. In tertiary buildings, such as offices or schools, the Advizeo platform facilitates this management.

Thanks to the Advizeo cockpit, systems can be adjusted immediately to reduce energy consumption.

Acting in stages: planning an energy performance approach

Acting in stages helps to better manage energy performance. This method simplifies projects and optimizes results.

Carry out an energy audit to analyze your building's energy consumption. It may be compulsory or voluntary, depending on the type of project.
Identify priorities through occupant surveys. This will help you determine where to invest to maximize gains.
Define a clear, structured action plan. Prioritize work such as insulating the envelope or optimizing the heating system.
Install monitoring tools such as connected meters. These tools quickly detect deviations and adjust usage.
Measure the impact every month or year to check progress with performance indicators.
Use the OPERAT platform, adapted to commercial buildings, to ensure better regulatory monitoring.
Optimize your return on investment by seeking financial aid such as CEE, MaPrimeRénov', or eco-PTZ loans.
Launch your projects during strategic periods with public or private calls for projects to maximize available funding.
Implement a continuous improvement strategy based on collected data to regularly adjust your energy actions.
Clearly explain each step to stakeholders to ensure their understanding and commitment to this globally beneficial process.

Energy audit: mandatory or voluntary

Energy audits are compulsory for commercial buildings over 1000 m². This measure also applies to the sale of a building for professional use.

It identifies energy use and proposes actions to reduce consumption. This approach is in line with the Tertiary Sector Decree, which sets ambitious targets for the gradual reduction of energy consumption. A serious audit must analyze equipment, insulation, building materials and occupant behavior.

A voluntary audit offers a real opportunity for optimization, even for small buildings. It helps define a clear, prioritized action plan. This service, often accompanied by a rapid financial return, enhances the value of assets and reduces energy costs.

The use of tools such as sensors and meters further enhances the effectiveness of these initiatives.

Define a prioritized action plan

Defining a prioritized action plan helps to reduce consumption rapidly. It also enables effective investment in sustainable solutions.

Identify areas of high consumption by carrying out an energy audit. An audit may be compulsory for certain buildings, such as industrial or commercial buildings.
Classify actions according to their impact and cost, using a simple matrix. For example, insulating attic space offers quick gains with little investment.
Prioritize measures with immediate gains, such as replacing light bulbs with LEDs or installing thermostatic valves.
Evaluate structural investments, such as replacing boilers with efficient systems or improving the building's airtightness.
Integrate monitoring tools such as Building Management Systems (BMS). These systems optimize energy management on an ongoing basis, and provide active control.
Plan each stage on a clear, precise schedule. The aim is to regularly measure progress and adjust the plan if necessary.
Allocate funding using available grants: CEE, MaPrimeRénov', éco-PTZ, or local subsidies adapted to public or private projects.
Implement each action according to your priorities, without delaying those that offer a rapid and high return on investment.
Monitor the reduction in consumption on a monthly basis after each stage of implementation, to guarantee the effectiveness of the overall plan.

Monitoring, evaluation, return on investment

Monitoring energy consumption enables you to detect discrepancies quickly. Installing meters and sensors helps to measure data in real time. Using monitoring tools simplifies analysis.

Public or commercial buildings can integrate BMS or IoT for intelligent control. Monthly monitoring of key indicators such as energy cost or reduction achieved optimizes the action plan.

Every action must offer a clear return on investment. Replacing equipment with efficient models can cut energy costs by up to 30%. LEDs, for example, pay for themselves in 1 to 2 years, thanks to reduced consumption.

An energy audit will identify priorities for maximizing long-term savings.

Financing energy-saving measures

Subsidies such as MaPrimeRénov', CEE or éco-PTZ reduce the cost of work. Local grants also support energy renovation projects. These schemes aim to replace old equipment with more efficient solutions.

They encourage active management of energy consumption.

Public buildings can benefit from dedicated calls for projects. Third-party financing and energy performance contracts simplify investment. These mechanisms spread out expenditure and guarantee a rapid return on investment.

Available grants: CEE, MaPrimeRénov', eco-PTZ, local subsidies

Buildings consume a lot of energy. Financial assistance is available to reduce these costs and improve performance.

Energy Savings Certificates (CEE)
These encourage work to reduce energy consumption. Energy suppliers finance projects such as insulation or equipment replacement. The amount depends on the savings achieved and the type of work carried out.
MaPrimeRénov'
This aid supports renovations to make homes more energy-efficient. It is available to both owner-occupiers and landlords, depending on their income. Amounts range from 15% to 90% of costs, according to the official scale.
Zero interest eco-loan (éco-PTZ)
Finances up to €50,000 worth of interest-free work over a maximum of 20 years. Eligible types of work include the installation of high-performance systems or thermal insulation of the building.
Local grants
Some local authorities offer additional grants for specific homes or buildings, subject to certain conditions. For example, a local authority may finance up to 30% of the cost of replacing an old heating system with an environmentally-friendly one.
Can be combined
These subsidies can often be combined, increasing the benefits for users and local networks committed to an eco-responsible approach.

Calls for projects for public or commercial buildings

Calls for projects support the reduction of energy consumption. For public and commercial buildings, there are schemes such as CEE (Certificats d'Économies d'Énergie) and DSIL (Dotation de Soutien à l'Investissement Local).

Local authorities can finance insulation work or replace energy-hungry equipment.

It's essential to keep an eye on announcements from regional authorities, ADEME and European funds such as Feder. These projects often target ecological renovations in public services.

They also allow for third-party financing or energy performance contracts.

Third-party financing and energy performance contracting

Energy performance contracts (CPE) guarantee measured energy savings. It enables deferred financing through third-party financing. A company invests in the work and is reimbursed from the savings achieved.

This system reduces initial costs for small local authorities and landlords.

This model is ideal for modernizing public or residential buildings. It encourages the implementation of a sustainable action plan. With this approach, energy consumption is reduced, and ecological impact is minimized.

Measuring results and aiming for continuous improvement

Monitor monthly and annual consumption to detect variations. Use performance indicators to evaluate each action taken. Install sensors and meters to obtain accurate, real-time data.

Adjust actions according to observed results to maintain an effective action plan.

Implement automatic controls to optimize systems. Insulate heating networks to improve energy efficiency. Set clear short- and long-term objectives to guide efforts.

Involve occupants to drive continuous improvements throughout the building.

Monitor monthly and annual consumption

Use an Excel spreadsheet to record your monthly consumption. Read your electricity, water and gas meters regularly. This simple method will help you keep better control of your energy consumption.

Be rigorous.

Analyze variations from month to month. Identify consumption peaks quickly. Compare annual data to assess the effectiveness of your action plan.

Aim for continuous improvement by adjusting your habits or equipment if necessary.

Performance indicators

Performance indicators measure the impact of actions on energy consumption. kWh/m².an measures energy efficiency per surface area. Savings in euros track direct financial gains.

Tons of CO₂ avoided show the environmental impact.

Set realistic targets by analyzing current data. For example, reduce consumption by 20% in three years. Comply with obligations such as the tertiary sector decree, which imposes a gradual reduction in energy use in certain buildings.

A good action plan will help you reach these targets quickly.

Use data to adjust actions

Data identifies areas of over-consumption. Sensors analyze energy use in real time. An intelligent system detects deviations and provides early warning. For example, an abnormal rise in heating consumption indicates an insulation problem.

These tools guide you towards targeted, effective action.

Data can also be used to obtain subsidies, such as MaPrimeRénov' or CEE. Precise reports on consumption strengthen dossiers. Artificial intelligence can further optimize plans.

It suggests solutions adapted to reducing energy impact while remaining eco-responsible.

Conclusion

Reducing the energy consumption of buildings is essential. Every action counts, from the choice of efficient equipment to good behavior. Improving insulation and optimizing technical systems make a real difference.

The targets set for 2030 call for collective efforts. Let's act now for a sustainable future.

FAQ

1. How can we reduce energy consumption in buildings?

Energy consumption can be reduced by insulating walls and roofs, using environmentally-friendly materials and installing double-glazed windows.

2. What equipment can reduce energy consumption?

Equipment such as LED light bulbs, smart thermostats and solar panels help save energy.

3. Why choose eco-friendly building solutions?

Eco-friendly solutions reduce greenhouse gas emissions, protect the environment and lower energy bills.

4. What simple actions can reduce energy consumption?

Turning off the lights, turning down the heating when you're away and using energy-saving appliances are all effective ways of reducing energy consumption.

To find out more :

Source :

Reducing energy consumption in buildings: Simple, concrete actions for managing real estate assets | Cerema