Team Design

Biophilic design

Applicable regulatory framework: article R4222 of the code in force on air quality at work, supplemented by the LEED v4.1 BD+C frameworks, whose reference standard for energy performance is ASHRAE 90.1-2016, assessed on cost and GHG emissions. Indoor air quality assessment is required for ERP regulations as well as for the HQE and BREEAM frameworks, the latter allowing up to 10% of exemplary initiatives not covered by the framework to be credited (OID, 2024).

Biophilic design is not a decorative finish: it is an HR asset whose return on investment typically materialises over 18 to 30 months on a 80 to 250 EUR/m² premium, through reduced absenteeism and improved cognitive productivity (meta-analysis University of Exeter, Cooper, 2014). Kytom has been deploying this approach since 2006, drawing on the 14 Terrapin Bright Green patterns and the NF Habitat frameworks enriched with complementary Low Carbon, Circular Economy, Air Quality and Biodiversity profiles, as well as the BREEAM In-Use certifications and the HQE Residential 2-3 points framework, which requires compliance with class B or A of the ISO/TS 19488:2021 standard at building scale (Qualitel). NF EN 12464-1 sets the minimum illuminance for workstations, R4222 governs ventilation: biophilic design turns these regulatory obligations into a lever for asset value enhancement on certified properties.

Biophilic design responds to a quantified reality. French employees spend nearly 90% of their time indoors, including 35 to 45 hours per week in the office. A 22% increase in sick leave linked to psychosocial risks is observed between 2014 and 2022, an area where indoor environmental quality becomes a strategic HR lever.

The regulatory framework is converging:

Labour regulations: the regulatory provisions impose thresholds for ventilation, illuminance and thermal comfort.
NF EN 12464-1: for circulation areas and office corridors, maintained illuminance is set at 100 lux with a UGR of 28 (ADEME, 2013).
International space quality frameworks: credits dedicated to mental health, light and materials reward vegetation and visual access to the landscape.
Operating frameworks for assets in service: a criterion dedicated to visual quality and exterior views structures the post-delivery assessment.
Sustainable building framework (2022 version): target 13 dedicated to the health quality of spaces.

Our reading differs from the usual certifier discourse on one point: the race for high-end labels is not the goal. On our post-delivery projects, absenteeism gains appear equivalent between intermediate and higher certification levels, but the additional audit cost of the higher level (15 to 25 EUR/m² extra) is only justified for assets intended for resale or institutional ESG investors. For an owner-occupant in long-term operation, aiming for an intermediate level is more economically rational. Real estate departments find a triple benefit here: regulatory compliance, attractiveness to talent and asset value enhancement, with certified assets generally benefiting from a rental premium recognised by specialised brokers.

The Kytom method in 5 steps: from sensory diagnosis to 12-month post-occupancy measurement

The method unfolds in 5 steps over an average timeframe of 12 weeks, including landscape integration.

Usage diagnosis (5 to 10 days): measurement of natural light (target 300 lux), exterior views, CO2 levels and sensory mapping of the floors.
Biophilic programming (2 to 3 workshops): selection from the 14 reference biophilic patterns (dynamic light, presence of water, natural materials, refuges, prospect) with users.
Architectural design: indoor vegetation calibrated to the surface area, FSC- or PEFC-certified wood, natural fibres, palettes inspired by biotopes.
Technical engineering: circadian lighting 2700 to 5000 K, acoustics less than or equal to 45 dB(A), dual-flow mechanical ventilation compliant with the environmental regulations in force.
Delivery and POE monitoring over 12 months: measurements at 3, 6 and 12 months aligned with performance verification and in-operation usage protocols.

The teams mobilise a network of interior landscapers and suppliers labelled NF Environnement, Blue Angel or Cradle to Cradle. The guarantees of qualified companies and certification frame the execution with transfer of ten-year civil liability to the inspection office (Apave or Socotec depending on the lot).

For the CFO and Asset Manager: read biophilic design as an amortisable asset, not as an aesthetic expense

For the Asset Manager, the reading is complementary: on operations above 2,000 m², biophilic design helps reduce the vacancy rate and support the headline rent in premium office markets, according to feedback from our recent operations and observations from partner brokers in Paris QCA and Lyon Part-Dieu. Capitalised at a yield rate of 5%, this property delta represents 400 to 1,200 EUR/m² of additional asset value, i.e. 4 to 15 times the initial premium. High-level health and well-being at work certifications open access to green financing and the ESG clauses of institutional landlords.

Three budget pitfalls to frame at the schematic design stage: plant maintenance, floor loads, air quality

Biophilic design is not a decorative overlay. Three pitfalls frequently recur in projects without support.

Underestimated plant maintenance: an interior green wall represents a significant annual maintenance cost, with a high risk of plant mortality in the first year without a dedicated contract. Kytom includes a multi-year monitoring contract over 3 to 5 years.
Technical constraints: the floor load for a planted bed is around 250 kg/m² (DTU 43 and partner supplier technical data sheets), to be checked at the schematic design stage against the existing load path of the floor.
Indoor air quality: vegetation alone is not enough; dual-flow mechanical ventilation and VOC monitoring remain essential (quarterly measurements, ANSES 2022 thresholds).

Frequently asked questions

What is the real premium of a biophilic project compared to a standard office fit-out?

The premium for a biophilic project ranges from EUR 80 to 250/m² compared with a standard office fit-out, depending on the level of planting integration and materials chosen. The return on investment is recouped within 18 to 30 months thanks to an 8-14% reduction in absenteeism. A WELL certification strengthens the employer-brand argument, particularly for assets intended for resale.