Environmental impact

The Two Sides of an Office Building’s Carbon Footprint

To understand the environmental impact of an office building, it is important to distinguish between two types of emissions that are often confused:

“Grey” carbon, i.e., construction. These are the emissions generated by the manufacture of materials (concrete, steel, glass, insulation), their transport to the construction site, and the construction itself. According to the Observatoire de l'Immobilier Durable (OID), the initial construction of an office building emits approximately 840 kg of CO2 per m². When major renovation work is factored into the life cycle, this figure rises to 1,400 kg of CO2 per m². A new 5,000 m² building therefore emits approximately 4,200 tons of CO2 before the first employee even moves in. And unlike operational carbon, these emissions are irreversible; they cannot be “offset” by optimizing building operations.

“Operational” carbon, i.e., daily use. These are emissions related to the building’s operation: heating, air conditioning, ventilation, lighting, elevators, and IT equipment. In France, an office consumes an average of 200 to 350 kWh/m²/year (depending on the building’s age and performance). Thanks to France’s energy mix (highly low-carbon due to nuclear power), this amounts to approximately 10 to 30 kg of CO₂/m²/year. This is significantly less than in countries dependent on gas or coal, but it remains substantial on the scale of the national commercial building stock.

Ultimately, the best way to reduce this footprint is to reuse before building.

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The French paradox: we’re building while millions of square meters stand empty

The French commercial real estate market presents a glaring contradiction:

On one hand, between 4 and 5 million square meters of new or renovated office space are delivered each year in the Île-de-France region. Each new square meter emits approximately 840 kg of CO2 in gray carbon (source: OID).

On the other hand, the vacancy rate in the Île-de-France region averages 8 to 9%, and exceeds 15% in certain areas. Added to this are “occupied but underutilized” spaces: companies that pay for 1,000 m² but actually use only 600 m² due to remote work.

This paradox can be partly explained by a market that operates in silos: developers build new properties because that is their business, investors buy new properties because the returns are better, and tenants want new properties because they are more efficient. Meanwhile, existing properties are deteriorating due to lack of occupancy and maintenance.

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The Commercial Real Estate Decree: What the Law Actually Requires

The Commercial Real Estate Decree (Decree No. 2019-771 of July 23, 2019) is the major regulatory requirement for office real estate in terms of environmental standards. Here’s what you need to know:

Who is affected? All buildings (or parts of buildings) used for commercial purposes with a floor area of over 1,000 m². This includes offices, as well as retail, hospitality, healthcare, and education facilities.

What are the requirements? Reduce the building’s final energy consumption by 40% by 2030, 50% by 2040, and 60% by 2050, compared to a base year chosen between 2010 and 2019. Alternative: Meet an absolute consumption threshold (which varies depending on the type of building and climate zone).

How to report? Through the OPERAT platform (Observatory of Energy Performance, Renovation, and Actions in the Tertiary Sector), managed by ADEME. Those subject to the requirement must enter their annual consumption data there.

What are the penalties? In case of non-compliance: a formal notice, followed by the publication of the company’s name on a public list (“name and shame”). The fine can reach €7,500 for legal entities. But the real risk is reputational and financial: a non-compliant building loses value and rental appeal.

The link to occupancy: an occupied building is easier to manage than an empty one. The occupant has an interest in optimizing energy consumption (and is required to do so). A vacant building, on the other hand, consumes energy “for nothing,” and its owner does not always have the means to invest in energy efficiency without rental income.

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6 concrete steps to reduce the environmental impact of your offices

1. Measure your actual energy consumption. Before taking action, quantify your usage. Track your energy consumption by category (heating, air conditioning, lighting, IT) and by area. Most companies find that 20 to 30% of their energy consumption comes from unoccupied areas that are heated and lit by default.

2. Optimize before renovating. Control systems (programming heating and air conditioning based on actual occupancy), LED lighting with motion sensors, and smart ventilation management can reduce consumption by 15 to 25% without major construction work. These are the “quick wins” of the commercial building regulation.

3. Reduce your floor space to the bare minimum. Every unused square meter consumes energy. Going from 1,000 m² to 800 m² by adopting a flex office automatically reduces your consumption by 20% and your rent by the same amount.

4. Make use of your excess space rather than leaving it empty. Unoccupied space continues to consume energy (heating to prevent freezing, minimal ventilation, emergency lighting). By entrusting it to an operator who activates and occupies it, you reduce energy waste while generating revenue. This is the “reuse what already exists” approach that Sora is based on.

5. Choose renovation over new construction. If you need to move offices, consider a renovated building rather than a new one. Renovation emits 50 to 70% less embodied carbon than new construction, for comparable energy performance.

6. Incorporate environmental criteria into your real estate decisions. Request the Energy Performance Certificate (EPC), verify compliance with the Tertiary Decree, and ask the owner about their reduction plan. An energy-efficient building will cost you less in operating expenses and enhance your CSR efforts.

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Environmental certifications to know

HQE (High Environmental Quality). The leading French certification. It evaluates 14 criteria across 4 themes: eco-construction, eco-management, comfort, and health. Three levels: Good, Very Good, Excellent.

BREEAM (Building Research Establishment Environmental Assessment Method). A British standard, widely used in Europe. Six levels from Pass to Outstanding. Particularly demanding regarding water management and biodiversity.

LEED (Leadership in Energy and Environmental Design). An American standard recognized internationally. Four levels ranging from Certified to Platinum. Strong emphasis on energy efficiency and indoor air quality.

E+C- Label. An experimental French label that anticipates the RE2020 regulations. The “E+” assesses renewable energy production, while the “C-” evaluates the carbon footprint across the entire life cycle.

These certifications are not mandatory, but they are becoming a key factor for tenants and a selling point for property owners. A building certified as HQE Excellent rents for 5 to 10% more than an equivalent non-certified building.