Green value: what energy performance is really worth, homes to offices

On 1 January 2030, two regulations converge. The Décret tertiaire (France's tertiary decree on energy savings in commercial buildings) targets a 40% cut in final energy consumption^{[2][2]RegulationLégifrance, “Decree No. 2019-771 of 23 July 2019 on obligations to reduce final energy consumption in commercial buildings” (Décret tertiaire)See in sources ↓}. The BACS decree (French decree 2020-887 on building automation and control systems) requires a BMS on heating or air-conditioning systems above 70 kW^{[3][3]RegulationLégifrance, “Decree No. 2020-887 of 20 July 2020 on building automation and control systems in non-residential buildings” (BACS decree)See in sources ↓[4][4]RegulationLégifrance, “Decree No. 2025-1343 of 26 December 2025”, postponing the BACS deadline for 70 to 290 kW systemsSee in sources ↓}. In front of the buyer or the valuer who sets the sale price of a building, a label will no longer prove anything. We explain what underpins green value in real estate, from homes to offices, then how to prove it before the transaction.

What is green value and what are its criteria?

A definition: the share of market value linked to energy and environmental performance

Green value is the share of a property's market value that comes from its energy and environmental performance. The premium is a price gap. You compare two properties in the same area and of the same size, which differ only by their DPE rating (the French Energy Performance Certificate, or EPC) or their energy consumption. In France, the notion first took hold in the housing market, houses or flats used as homes.

For offices, it changes nature. A sustainable real estate asset is not judged on environmentally friendly talk. It is judged on its measured environmental impact, year after year. The green value of a building then shows in its actual consumption.

Green premium and brown discount: two readings of the same gap

The same gap reads in two directions. For the efficient property, it is a green premium, also called green value (in French you will sometimes read « valeur verte immobilier »). For the energy-hungry property, it is a brown discount: it sells less well than comparable neighbors. Both notions measure the same gap, seen from the buyer's side or from the seller's.

For a seller, a brown discount gets negotiated far faster than a premium gets demonstrated.

Home or commercial building: what underpins green value

The green value of homes rests on a document, the DPE rating. That of a commercial building rests on consumption declared every year on OPERAT, the public service platform run by ADEME, under the Décret tertiaire^{[2][2]RegulationLégifrance, “Decree No. 2019-771 of 23 July 2019 on obligations to reduce final energy consumption in commercial buildings” (Décret tertiaire)See in sources ↓}. The table below compares the two regimes on five criteria, deadlines included.

Read line by line, the table reveals a difference in nature. For a home, a better class is enough to keep it lettable. For a building, the same 2030 deadline changes the game: the BACS decree^{[3][3]RegulationLégifrance, “Decree No. 2020-887 of 20 July 2020 on building automation and control systems in non-residential buildings” (BACS decree)See in sources ↓[4][4]RegulationLégifrance, “Decree No. 2025-1343 of 26 December 2025”, postponing the BACS deadline for 70 to 290 kW systemsSee in sources ↓} requires heating and air-conditioning control that produces precisely the data a buyer will ask for.

Energy criteria: label, heating and cooling, actual operation

The classic energy criteria are well known: DPE rating, insulation, heat and domestic hot water production. An air-to-water heat pump improves the score on paper.

A class is not a performance. We have all come across that HQE building that ticks every box at handover, then overconsumes three to five years later because operation did not keep up. For an office, the deciding criterion remains the actual consumption of heating and cooling over time. A DPE for commercial buildings gives a snapshot of it. Only operation tells whether an efficient building stays efficient.

Environmental criteria: carbon, greenhouse gases and building certifications

The environmental side widens the view to carbon: the building's carbon footprint, its greenhouse gas emissions in operation and the environmental issues of its materials. HQE, BREEAM or LEED certifications structure this reading. They attest an environmentally friendly design. Actual environmental performance, however, depends on what operation does with the building once delivered. Its environmental impact is measured afterwards, never before.

How does green value influence price and what issues does it raise?

Homes: the DPE rating and the timetable for energy sieves set the discount

The green value of a home reads first as a discount. It follows the DPE rating and the timetable for the ban on letting. Energy sieves ("passoires énergétiques", homes rated G or F) rated G have been excluded from new leases since 1 January 2025. F-rated homes will be in 2028^{[1][1]RegulationLégifrance, “Law No. 2021-1104 of 22 August 2021 on combating climate change and strengthening resilience to its effects” (Climate and Resilience Act)See in sources ↓}. A better-rated house or flat sells for more, because it stays lettable.

An energy-hungry property still sells. The buyer simply deducts the works from the sale price.

Offices: green premium and brown discount work through rent, vacancy and yield

For offices, the valuer does not compare prices per square meter: they start from income. Performance acts on three variables. Achievable rent first, because a demanding tenant compares service charges before signing. Vacancy next, which lengthens on a poorly documented building. The yield last, which the valuer and the bank raise when risk increases. Green value or brown discount, a building's return comes out changed.

CRREM pathway and stranded asset: when future consumption enters market value

Decarbonization pathways set, year after year, a carbon intensity not to be exceeded. An asset that falls off the pathway becomes a stranded asset. Its future consumption, its greenhouse gas emissions and the works to plan already weigh on its market value today. The valuer must take this into account, even when the deadline seems far off. We detail this mechanism in our article on CRREM and stranded assets.

The Notaires de France studies: the green value of homes measured on transactions

In France, the most quoted measurement comes from the Notaires de France (the French notaries' national body). Their studies on the green value of homes rely on actual transactions. Each house or flat sold is matched with comparable properties that differ only by their rating. The trend tracked from one edition to the next concerns the gap between classes, not a price per square meter. A figure is read in the primary edition, with its year and its area.

Offices: what the OID and market studies measure on the green premium

For offices, the Observatoire de l'immobilier durable (OID, the French sustainable real estate observatory) and several broker studies try to isolate a real estate green premium in France. Green value appears in their analyses. Yet it reads less clearly than for homes. The sample of transactions remains narrow and each sale mixes location, tenancy status and performance. A published gap describes a market, never your building.

The limits of the figures: is green value really a selling point?

Green value ranges circulate everywhere, without a year or a primary source. In front of a buyer or a bank, they carry no weight. The impact of green value on a price is discussed with consumption data, the state of the BMS and a regulatory timetable. The market's awareness is real. It is not enough to sell for more a property that demonstrates nothing.

A premium is demonstrated property by property.

The 1 January 2030 deadline: Décret tertiaire and BACS decree converge

On 1 January 2030, two obligations meet. The Décret tertiaire targets a 40% cut in final energy consumption^{[2][2]RegulationLégifrance, “Decree No. 2019-771 of 23 July 2019 on obligations to reduce final energy consumption in commercial buildings” (Décret tertiaire)See in sources ↓}. The BACS decree requires a BMS in buildings whose heating and air-conditioning systems exceed 70 kW^{[4][4]RegulationLégifrance, “Decree No. 2025-1343 of 26 December 2025”, postponing the BACS deadline for 70 to 290 kW systemsSee in sources ↓}. The 290 kW threshold has already applied since 1 January 2025^{[3][3]RegulationLégifrance, “Decree No. 2020-887 of 20 July 2020 on building automation and control systems in non-residential buildings” (BACS decree)See in sources ↓}. A BMS that works serves both: it keeps the energy trajectory on track and produces the evidence demanded at resale.

Did you know? The BACS decree does not require any class of the NF EN ISO 52120-1 standard^{[3][3]RegulationLégifrance, “Decree No. 2020-887 of 20 July 2020 on building automation and control systems in non-residential buildings” (BACS decree)See in sources ↓}. It sets its own functional requirements, while the market keeps repeating "class B minimum". Regulatory compliance and eligibility for CEE energy-savings certificates remain two separate logics.

Environmental issues thus become documents in a file and stop being statements of intent.

Green lease and environmental annex: who owes what between landlord and tenant?

The green lease organizes a data exchange between landlord and tenant. The environmental annex to the lease lists the equipment, its consumption and each party's commitments. The landlord passes on what it has. The tenant shares its own readings. Each then takes its share of the improvement program. Without reliable meters or usable history, this annex remains a formality, signed then forgotten.

How to increase a property's green value?

Homes: thermal insulation, windows and air-to-water heat pump

To increase the value of a house or a flat, the levers are well known. Thermal insulation comes first, then the windows and the front door. An air-to-water heat pump then takes over heating and domestic hot water. These renovation works raise the home's rating. A refitted bathroom or a wooden floor improves comfort, not the green value of your home.

Commercial buildings: why works do not come first

An office building in operation rarely loses its performance because of a failed piece of equipment. The first source of erosion is post-handover drift: modified setpoints, overrides never lifted, shifted HVAC schedules. The diagram below walks through the sequence we follow before any CAPEX decision, with the deliverable each step produces.

This sequence comes down to four verbs: make reliable, stabilize, measure, then invest. Committing CAPEX on a BMS that does not hold its setpoints amounts to funding works whose effect nobody will be able to measure. The risk is twofold. Energy drift continues under the new thermal insulation, while the promised saving remains unverifiable in front of the valuer.

Let us go through the sequence step by step, starting with the actual state of the instrumentation.

Step 1: make the BMS and the meters reliable

Take a site that displays 500 meters in supervision without anyone knowing which ones are reliable. Those meters prove nothing. The BMS audit spots disconnections, duplicates, invisible drifts and data gaps. It also checks the heating and cooling points reported to the BMS (the AHU that overconsumes day after day until the filter change alarm). Thanks to this inventory, energy drift finally becomes visible.

Step 2: stabilize operation by lifting manual overrides and schedule exceptions

The VIP complaint introduces temporary settings that last for years. Operations retuning lifts, one by one:

• the manual overrides left active;
• schedule exceptions never lifted;
• HVAC schedules shifted after an event;
• setpoints raised after a VIP complaint.

Once this work is done, degraded mode stops being the norm. The building returns to stable behavior, without which no measurement makes sense.

Step 3: measure savings against a degree-day-corrected baseline

Without a baseline corrected for heating degree days (HDD, called DJU in France), a mild winter passes for an energy saving. The method sets a reference period, a weather adjustment model and takes occupancy into account. The comparison becomes verifiable by a third party. It is the best defense in front of a valuer and the foundation of any serious energy performance contract.

The deliverable is a measurement report under the IPMVP protocol, which the buyer can have audited.

Step 4: invest in a multi-year works plan based on measurements

CAPEX comes last. The multi-year works plan is sized on measured consumption rather than on ratios. Every euro invested to improve the asset becomes demonstrable: before, after, weather-corrected. Works carried out on this basis make an efficient building defensible at resale. A value-add strategy finds a quantified argument in it to increase value, without having to assume it.

How to estimate a property's green value?

Homes: the comparison method used by notaries and agents

For the green value of a home, the notary or the agent applies the comparison method. They gather properties recently sold in the same market, of similar size and area. Only the class differs. The sale price gap observed on these completed transactions gives the premium. One piece of advice: take the general condition into account, because a renovated house does not compare with a home to renovate.

Commercial buildings: why comparing sales is not enough

For an office, comparable transactions are rare and heterogeneous: location, size, tenancy status, nothing is alike. The valuer therefore estimates a building's market value from its rental income and the capitalization rate applied. Performance weighs on both. The market value obtained depends on what the seller documents. The bank financing the acquisition reads exactly the same file.

Measured consumption and control history: what the buyer looks at on resale

A label freezes the state of the building on the day of the assessment. A continuous, weather-corrected consumption history shows that performance holds, season after season. The buyer and their bank look in it for how changes of use or tenant were taken into account. The same document answers the valuer. One question remains that few owners ask themselves: who, in your organization, could produce three years of clean history in a week?

The evidence file for green value in a commercial building

For commercial buildings, green value is defended with documents, rarely with a label alone. Here are the six documents a buyer or a valuer will ask for before discussing a price. Tick those you could send tomorrow, without rebuilding anything.

The evidence file is not put together the week before the data room opens. OPERAT declarations accumulate from one year to the next, the baseline is frozen before any action and an IPMVP report assumes measurement started long ago. An empty box therefore points to a step of the sequence described above, most often making the meters reliable. With fewer than four boxes ticked, the discussion with the buyer, as with their bank, will slide toward a discount.

What Foobot brings to proving the performance of a commercial asset

BMS advisory: make the BMS and meters reliable before a due diligence

BMS advisory stands on its own: no AI phase is planned by default behind it. We first make the meters reliable, tracking down disconnections, data gaps, duplicates and invisible drifts. Our operations advisory then lifts manual overrides and restores consistent sequences. When equipment is declared obsolete, the "obsolete BMS" audit provides a second opinion before a full replacement is priced. Each completed mission ends with a deliverable that can be reviewed in due diligence.

Green value that holds up in front of the valuer starts with measurements

Green value is proven, document by document. For homes, the rating and sales comparison are still enough. For commercial buildings, the valuer, the bank and the buyer will ask for measured consumption. The 1 January 2030 deadline makes this evidence due^{[2][2]RegulationLégifrance, “Decree No. 2019-771 of 23 July 2019 on obligations to reduce final energy consumption in commercial buildings” (Décret tertiaire)See in sources ↓[4][4]RegulationLégifrance, “Decree No. 2025-1343 of 26 December 2025”, postponing the BACS deadline for 70 to 290 kW systemsSee in sources ↓}. Energy performance that is not measured is not valued. Before ordering works, go back to the six-document checklist and count what is missing. If your BMS already holds its setpoints, control can turn measured savings into a valuation argument. Let us look together at how to build this evidence on your buildings.

prove performance through control

Further reading:

• energy performance contract

FAQ - green value