Trial / Demo
IES Consultants used IES Virtual Environment (IESVE) across multiple simulation workstreams, achieving credits across energy, health & well-being, and passive design categories, to support the overall aim of achieving a BREEAM Excellent rating.
IES Consulting was appointed by ML2S, an architectural company focused on sustainable solutions, to deliver a comprehensive BREEAM New Construction International V6 assessment for a new four-storey office building at Lomb Road, Budapest – a core and shell development of approximately 2,778 m² incorporating open-plan offices, meeting spaces and a large bike store. Their aim is to help their customers set and achieve environmentally conscious objectives, and IES Consultancy were vital partners in achieving their goals.
Achieving energy performance, with added variables
The project presented a distinctive challenge that’s all too familiar across commercial developments. As the building is a core and shell offering, the interior fit-out is the responsibility of individual tenants, meaning the owner could not fully control the energy performance of the completed building.
To address this, the owner introduced a legally binding green fit-out agreement covering all future tenants, committing them to LED lighting, occupancy sensors turning off all lighting within 30 minutes of vacancy, DALI-dimming systems in all regularly occupied rooms, VRF indoor units with a Specific Fan Power no greater than 0.6 W/(l/s), VAV dampers and CO₂ sensors in all high-density areas, and demand-controlled ventilation throughout.
This Tenant Lease Agreement formed a critical input to the IESVE simulation, allowing IES Consultants to model the full building, including tenant spaces, with high confidence in the projected performance – all with each item in the Tenant Lease Agreement correctly applied.
The services design was modelled in full detail within IESVE's ApacheHVAC application, including part-load efficiency curves, floor-by-floor VRF staging, and auto-sizing of cooling and heating coil capacities.
Modelling to ensure the best outcome
A key strength of the IES approach was the robust multi-scenario methodology applied to the ENE01 assessment. Rather than relying on a single base case model, IES Consultants ran various separate simulations:
1. The likely design (base case at 79.20 kWh/m²)
2. Comparing against ASHRAE 90.1 - 2019 and without Renewables (Result: 4 points)
3. A probable future weather scenario using a warmer climate file
4. A bad management factors scenario with equipment gains increased by 25% and increased % of internal gain and HVAC energy consumption as a consequence of weak maintenance procedures
5. An absence-of-passive-design scenario removing shading devices and worsening the envelope by 25%
6. And a worst-case scenario combining all adverse factors (reaching 102.03kWh/m²)
This range of off-axis studies, structured in line with BREEAM GN32, GN48 and CIBSE TM54 guidance, gave the design team and BREEAM assessor clear evidence of the building's resilience to real-world performance variability, and it also identified the passive design strategies that were subsequently modelled separately under ENE04.
The Benefits of Using IESVE
Working across four BREEAM credit categories simultaneously, the IES team used IESVE as a single, integrated platform for energy modelling, thermal comfort, passive design analysis, and daylighting, eliminating the data inconsistencies that arise when separate tools are used for each discipline. The same validated building geometry and construction data underpinned every assessment, ensuring consistency between reports and giving the design team confidence that improvements in one area would not compromise performance in another.
The ability to rapidly test passive design scenarios within a single environment meant the project team could make informed design decisions early, reducing risk and supporting a robust BREEAM submission. For a developer looking to prove outstanding performance in a competitive Central European market, IESVE provided the analytical depth and evidential rigour needed to achieve it.
