All categories · Q&A
🌿 Energy, Sustainability & Building Performance Analysis
Building performance analysis software takes geometry and data from a BIM model and simulates how the building will behave: energy use, heating and cooling loads, daylight, glare, thermal comfort, overheating, moisture and embodied carbon. In a BIM workflow these tools sit between the authoring model (Revit, Archicad, Rhino) and compliance or certification outputs (Part L, ASHRAE 90.1, LEED, BREEAM, EN 15978 whole-life carbon). Exchange usually happens through gbXML, IFC, IDF/OSM or direct plug-ins, and the quality of the analytical model depends heavily on how the BIM model was built.
What is IES VE and what does the 'VE' stand for?
IES VE is the Virtual Environment, a suite of building performance applications from Integrated Environmental Solutions (IES), a Glasgow-based company. All applications share one 3D model created in ModelIT, and the core dynamic thermal engine is ApacheSim. Other modules cover HVAC (ApacheHVAC), daylight (RadianceIES), solar (SunCast), CFD (MicroFlo) and UK/US compliance. The current release is VE 2026, published in September 2026.
How do I get a Revit model into IES VE?
There are three common routes. The IES Revit plug-in exports the Revit energy analytical model directly into ModelIT. Alternatively export gbXML from Revit (Analyze tab, Energy Settings, then Export gbXML) and import it in ModelIT, where constructions are assigned automatically. The third route is Pollination, whose Revit plug-in produces a cleaned model that IES lists as an official import path. In every case, check that rooms or spaces are bounded and that the analytical surfaces are closed before exporting.
Is there an official IES certification I can put on my CV?
Yes. IES runs a VE Accreditation programme with exams on the VE compliance applications. IES states that these qualifications are accepted by its accreditation-scheme partners as proof of software competency when applying to become an accredited energy assessor. Preparation options include on-demand learning, live online courses, face-to-face events and a free Getting Started course.
What simulation engine does DesignBuilder use?
DesignBuilder is a graphical front end built on EnergyPlus, the U.S. Department of Energy engine. It adds its own 3D modeller, a Radiance daylighting module and a CFD module. Because the EnergyPlus input file is accessible from the interface, advanced users can inspect or edit IDF objects directly. The vendor is DesignBuilder Software Ltd in Stroud, UK, and the current release is v2025.1.
About DesignBuilder · Certification
Do I have to buy all of DesignBuilder or can I license modules?
DesignBuilder is modular. The 3-D Modeller and Visualisation form the base, and you add Simulation, Daylighting, HVAC, Cost and Carbon, CFD, Optimisation or Scripting as needed. Licences are offered on both perpetual and subscription terms, and site network licences can combine any set of modules. A free 30-day evaluation and educational licences for universities are available.
About DesignBuilder · Certification
Can DesignBuilder be used for UK Part L compliance and is there training for it?
Yes. DesignBuilder provides SBEM and DSM (dynamic simulation) compliance workflows and publishes a list of approved versions. It runs a dedicated 'DSM Training and Exams' programme aimed at users who need UK certification, alongside overheating and SBEM courses. Approved-version lists, CIBSE weather data and SBEM/DSM manuals are provided with the training material.
About DesignBuilder · Certification
Who owns Sefaira today and which modelling tool does it work with?
Sefaira is owned by Trimble and is sold as part of the SketchUp family. You model simple massing in SketchUp with the Sefaira plug-in, then the cloud platform runs hour-by-hour annual simulations using EnergyPlus for energy and Radiance for daylight. The product is positioned for concept and schematic design, not detailed compliance.
About Sefaira · Certification
What kinds of results does Sefaira give me from a massing model?
Sefaira reports energy use and carbon emissions, thermal comfort, and three daylight metrics: daylight factor, direct sun exposure and annual daylight (spatial daylight autonomy). It also compares HVAC system types and sizes them. Results update as you change orientation, glazing ratio or shading, which is why it is used for option comparison in the first weeks of a project.
About Sefaira · Certification
Should I use Sefaira or IES VE for a LEED energy model?
Use Sefaira only for early comparative studies; it is not intended for the detailed, documented model a LEED Energy and Atmosphere credit or an ASHRAE 90.1 Appendix G submission requires. IES VE, DesignBuilder, EDSL Tas or an OpenStudio/EnergyPlus model give the control over schedules, HVAC and reporting that reviewers expect. A common pattern is Sefaira in concept design, then a rebuilt engineer's model in IES or DesignBuilder from the same BIM geometry.
About Sefaira · Certification
What is Autodesk Insight and do I need to buy it separately from Revit?
Insight is Autodesk's energy and carbon analysis service connected to Revit. It builds an energy analytical model from the Revit project, runs cloud simulation and presents energy use intensity, cost and, with Total Carbon Analysis, operational plus embodied carbon. It is included with a Revit subscription rather than sold separately. Autodesk's own learning collection 'Get started with Insight in Revit' is the official introduction.
About Autodesk Insight · Certification
Why does my Insight model show missing or strange spaces?
Insight relies on the Revit energy analytical model, which is generated from rooms or spaces and their bounding elements. If rooms are unplaced, not enclosed, or elements are not room-bounding, the analytical surfaces will be wrong. Check Energy Settings (Analyze tab) for the analysis mode, set the correct building type and location, ensure all rooms are enclosed and placed, and regenerate the energy model before sending to Insight.
About Autodesk Insight · Certification
Where does Insight get its embodied carbon factors from?
Insight's Total Carbon Analysis connects to Building Transparency's EC3 database of third-party verified Environmental Product Declarations. Revit materials and quantities are mapped to EC3 material categories so the embodied carbon can be estimated alongside the operational energy result. Because EC3 is free and open, the same factors can be checked outside Revit.
About Autodesk Insight · Certification
Is Autodesk Green Building Studio still available?
No. Green Building Studio was Autodesk's cloud energy service that ran DOE-2 and later EnergyPlus simulations on gbXML models uploaded from Revit. Its functionality was folded into Autodesk Insight, and the GBS web address now redirects to Autodesk's 'Get started with Insight in Revit' learning collection. Any tutorial that tells you to upload gbXML to GBS is out of date.
I have old Green Building Studio projects. What can I do with them now?
Green Building Studio allowed export of EnergyPlus IDF and DOE-2 INP files from a project. If you still hold those files, they can be opened in EnergyPlus (IDF) or in tools that read DOE-2 input. The original gbXML files can be re-imported into OpenStudio, DesignBuilder, IES VE or Pollination. New analysis should be started in Insight or a dedicated engine rather than trying to revive the retired service.
What does One Click LCA actually calculate?
One Click LCA is a cloud platform for life-cycle assessment of buildings and infrastructure. It calculates whole-life carbon and other environmental impacts across the life-cycle stages defined in EN 15978, supports national methods and certification schemes such as LEED and BREEAM, and can generate Environmental Product Declarations for manufacturers. The vendor says it covers more than 140 standards and methods and offers free live and on-demand training through its Academy.
About One Click LCA · Certification
How do I get quantities from my BIM model into One Click LCA?
The platform advertises more than 20 BIM and data integrations. Typical routes are the Revit and Archicad plug-ins, an IFC file export from any authoring tool, a gbXML file for energy-related data, or a spreadsheet import. After import you map each material or element to an EPD or generic dataset. The quality of the result depends on your model's material naming and on classification, so agree a naming convention before take-off.
About One Click LCA · Certification
How should I scope a whole-life carbon assessment in One Click LCA so it is comparable with other projects?
Fix the assessment boundary before modelling: reference study period (usually 50 or 60 years), included life-cycle modules (A1-A3, A4-A5, B1-B7, C1-C4 and D reported separately) and the building elements covered. Use the national or client method available in the tool (for example RICS or a national regulation template) so factors, scenarios and reporting units match. Document data quality for each mapping and keep the IFC or Revit export used for quantities with the report so the assessment can be audited.
About One Click LCA · Certification
What is Tally and which software does it run in?
Tally is a life-cycle assessment add-in that runs inside Autodesk Revit. It maps Revit materials to LCA datasets and reports embodied environmental impacts for the whole building or for design-option comparisons. It started as a joint project of KT Innovations, thinkstep and Autodesk and is now administered by Building Transparency. Tally 2025 supports Revit 2021 through 2026.
About Tally (tallyLCA) · Certification
Is Tally free?
No. The download page lists a Basic floating licence at USD 695 per year and a Premium floating licence at USD 995 per year, with a 10-day trial and educational licences on request. A rebuilt Tally 2.0, developed with C.Scale, is in beta and its site invites users to get started free, but the shipping Tally 2025 product is a paid annual licence.
About Tally (tallyLCA) · Certification
How does Tally connect to EC3?
Tally can export material quantities from the Revit model to EC3 and keep them synchronised. This lets the design team do the LCA in Tally and then hand the same quantities to procurement, where EC3 compares real product EPDs against a carbon budget. Tally 2.0 goes further by allowing product-specific EPDs inside the calculation itself.
About Tally (tallyLCA) · Certification
What is EC3 and how much does it cost?
EC3, the Embodied Carbon in Construction Calculator, is a free, open-access web tool from the non-profit Building Transparency. It contains a database of more than 50,000 third-party verified Environmental Product Declarations and lets you compare products in a category, set carbon budgets and evaluate supplier bids. The tool itself is free; only API access is priced separately.
About EC3 (Embodied Carbon in Construction Calculator) · Certification
Which other platforms feed data into EC3?
EC3 integrates with Autodesk Construction Cloud, Bentley iTwin, cove.tool, One Click LCA, Tally, Procore, 2050 Materials and Transparency Catalog, among others. In practice an LCA tool or BIM platform sends material quantities to EC3, and EC3 supplies EPD-based carbon factors back. Autodesk Insight's Total Carbon Analysis also draws on EC3 data.
About EC3 (Embodied Carbon in Construction Calculator) · Certification
Why do EC3 results show a range rather than a single number for a product category?
EC3 reports the distribution of global warming potential across all valid EPDs in a category and applies an uncertainty factor to each EPD depending on its type (product-specific versus industry-average) and data quality. Showing the conservative estimate and the range prevents teams from picking an optimistic value and helps set a realistic carbon budget. When you specify a product, choose the specific EPD so the uncertainty narrows.
About EC3 (Embodied Carbon in Construction Calculator) · Certification
What are Ladybug, Honeybee, Dragonfly and Butterfly?
They are the four main plug-ins of Ladybug Tools, an open-source environmental design toolkit for Rhino/Grasshopper. Ladybug handles weather data, sun path, radiation and comfort; Honeybee builds energy models (EnergyPlus/OpenStudio) and daylight models (Radiance); Dragonfly extends this to district and urban scale; Butterfly wraps OpenFOAM for CFD. The libraries are licensed under the GNU Affero GPL and are free to use.
About Ladybug Tools (Ladybug, Honeybee, Dragonfly, Butterfly) · Certification
What file formats does Honeybee use and can it read IFC?
Honeybee stores models in HBJSON, an open JSON schema, and Dragonfly uses DFJSON. From those it writes EnergyPlus IDF, OpenStudio OSM and Radiance files, and it can export gbXML. It does not read IFC directly; typical routes are Rhino's own IFC import, Rhino.Inside.Revit, or the Pollination Revit plug-in, which produces a clean HBJSON model. Weather comes from EPW files.
About Ladybug Tools (Ladybug, Honeybee, Dragonfly, Butterfly) · Certification
Can I run Ladybug Tools without Grasshopper, for example on a server?
Yes. The ladybug, honeybee and dragonfly Python packages can be installed with pip and used in scripts or notebooks without Rhino. There are command-line interfaces for translating HBJSON to IDF or OSM and for running simulations, which is how Pollination Cloud recipes are built. This makes it possible to batch hundreds of design variants on a Linux server or in CI, with Grasshopper used only for authoring.
About Ladybug Tools (Ladybug, Honeybee, Dragonfly, Butterfly) · Certification
How is Pollination different from Ladybug Tools?
Ladybug Tools is the free, open-source toolkit maintained by the community. Pollination is the commercial product line from Ladybug Tools LLC built on top of it: a Revit plug-in, a Rhino plug-in and a cloud platform for running simulations. The Grasshopper plug-in is free, while the Rhino and Revit plug-ins and cloud seats are paid subscriptions with a 30-day trial.
About Pollination · Certification
Which energy modelling formats can Pollination export to?
Pollination lists exports to Honeybee HBJSON, Dragonfly DFJSON, OpenStudio OSM, EnergyPlus IDF, gbXML (used by DesignBuilder and TRACE), IES VE GEM, eQuest INP, IDA ICE IDM and CBECC SDDXML. This makes it a translator between Revit or Rhino geometry and almost every mainstream BEM engine. IFC is not among the listed formats.
About Pollination · Certification
Why do BIM managers prefer the Pollination Revit plug-in over a plain gbXML export?
A native gbXML export from Revit reproduces every modelling imperfection: overlapping rooms, unbounded spaces, sliver surfaces. The Pollination plug-in extracts rooms, walls, windows and shades into a Honeybee model, offers validation and repair tools, and lets the user simplify geometry before export. The resulting model can then be written to gbXML, GEM, OSM or IDF as needed, so one clean-up serves several engines.
About Pollination · Certification
What is the difference between EnergyPlus and OpenStudio?
EnergyPlus is the simulation engine funded by the U.S. Department of Energy; it reads IDF or epJSON text files and has no graphical modeller. OpenStudio, maintained by NREL, is a software development kit that wraps EnergyPlus, adds the OSM model format, a gbXML importer and 'Measures' for scripted changes. The OpenStudio Application desktop interface is maintained separately by the OpenStudio Coalition. Both are free under BSD-style licences.
About EnergyPlus and OpenStudio (DOE / NREL) · Certification
Which operating systems does EnergyPlus run on and how often is it released?
EnergyPlus is released twice a year, in spring and autumn; the current release is 26.1.0. Installers are provided for Windows (including ARM64), macOS on Intel and Apple silicon, and Ubuntu Linux. OpenStudio SDK follows with a matching release, currently 3.11.0, and both are published on GitHub with changelogs.
About EnergyPlus and OpenStudio (DOE / NREL) · Certification
What is an OpenStudio Measure and why does it matter for enterprise workflows?
A Measure is a Ruby (or Python) script that programmatically modifies an OpenStudio model, runs the simulation or post-processes results. Firms build libraries of Measures for standard tasks such as applying an envelope package, swapping HVAC types or producing a QA report, then chain them in a workflow file. This is how large parametric studies and code-compliance baselines are automated reproducibly, instead of clicking through a GUI for each variant.
About EnergyPlus and OpenStudio (DOE / NREL) · Certification
What is ClimateStudio and what do I need to run it?
ClimateStudio is a Rhino plug-in from Solemma LLC for daylight, glare, energy, comfort and PV analysis. It requires an installed and licensed copy of Rhino 6, 7 or 8 on Windows and is sold as a subscription with commercial and educational options. It uses a fast path-tracing implementation of Radiance and EnergyPlus for energy modelling.
About ClimateStudio · Certification
Can ClimateStudio produce the LEED daylight credit metrics?
Yes. ClimateStudio computes spatial daylight autonomy (sDA) and annual sunlight exposure following IES LM-83, plus quality-view calculations, which are the inputs for the LEED v4 daylight and quality views credits. It also reports annual glare and can generate AIA 2030 reports automatically. Results are visualised directly on the Rhino geometry.
About ClimateStudio · Certification
When would I choose ClimateStudio over Ladybug Tools?
Both run in Rhino and use Radiance and EnergyPlus. ClimateStudio offers one-click wizards, a polished interface and very fast daylight results, so it suits architects who need reliable LEED daylight and glare outputs without building Grasshopper definitions. Ladybug Tools is free, fully parametric and more flexible, so it suits research, scripting and unusual workflows. Many offices use both: ClimateStudio for deliverables, Ladybug for exploration.
About ClimateStudio · Certification
What is EDSL Tas used for in the UK?
Tas, from Environmental Design Solutions Ltd in Milton Keynes, is a dynamic simulation suite used for UK Building Regulations Part L2 compliance, Energy Performance Certificates, TM52 and TM59 overheating assessments and BB101 school ventilation studies. The suite includes Tas Building Designer, Tas Engineering, Tas Systems for HVAC plant and Ambiens 2D CFD. The current version is 9.5.7.
About EDSL Tas · Certification
What formats can Tas import and export?
Tas imports gbXML from BIM tools such as Revit, and 2D or 3D DWG files for tracing plans and shading surfaces. It can also exchange EnergyPlus IDF and DOE-2 INP files, which lets US users move models to or from other engines. EDSL offers specific training on preparing Revit gbXML exports for Tas.
About EDSL Tas · Certification
Does EDSL offer accreditation for Tas users?
EDSL runs an accreditation process for Tas users alongside a free e-training portal with a Tas Engineering course and a Systems introduction. In the UK, software accreditation is usually combined with a personal competence scheme such as the CIBSE Low Carbon Consultant register to sign off Part L compliance, so check which scheme your client or local authority expects.
About EDSL Tas · Certification
What does WUFI simulate and who makes it?
WUFI is developed by the Fraunhofer Institute for Building Physics in Germany. It simulates coupled heat and moisture transport in multi-layer building components exposed to real weather, so it is used to check condensation, mould and drying risk in walls, roofs and retrofits. The family includes WUFI Pro (1D), WUFI 2D, WUFI Plus (whole building) and WUFI Passive (Passive House and PHIUS). WUFI Pro 7.2 was released in March 2026.
How is WUFI licensed?
WUFI is sold as time-limited licences rather than perpetual seats. WUFI Pro is offered as a 1-year licence with free updates and upgrades during validity, or a 5-year licence with free updates within the version and reduced-cost upgrades. WUFI Passive is available in 1-, 3- and 5-year terms. Fraunhofer also lists free WUFI versions with limited functionality.
When should a BIM project add a WUFI study on top of the energy model?
Add a hygrothermal study whenever the envelope has moisture risk that an energy model ignores: internal insulation retrofits, timber or CLT walls, flat roofs with vapour-closed layers, high-humidity spaces or unusual climates. The energy model gives U-values and loads; WUFI tells you whether the assembly will dry out or accumulate moisture over years. Take the layer build-ups from the BIM material assemblies so both models use identical constructions.
What happened to Autodesk Ecotect?
Ecotect was created by Square One Research as a visual tool for sun-path, shading, solar radiation, daylight and simplified thermal studies. Autodesk acquired it in 2008 and sold it as Ecotect Analysis until withdrawing it in 2015, pointing users to Revit energy analysis and later Insight. It is no longer sold or supported, although old tutorials still circulate.
What is gbXML and how is it different from IFC?
Green Building XML (gbXML) is an XML schema created specifically to move building geometry and thermal data from BIM tools to energy analysis tools; the current schema version listed by gbXML.org is 8.01 and it is maintained by an industry consortium including ASHRAE, DOE, NREL and Autodesk. IFC is the broader buildingSMART open standard for the whole building model. Most energy tools (IES, DesignBuilder, Tas, OpenStudio) read gbXML, while IFC is read mainly by LCA tools such as One Click LCA and by newer BIM-to-BEM converters.
Certification: Energy, Sustainability & Building Performance Analysis
Which tool should an architect use for early-stage energy feedback?
For SketchUp users, Sefaira gives fast energy and daylight comparisons in the cloud. Revit users get Autodesk Insight included in their subscription, with combined operational and embodied carbon. Rhino users can choose ClimateStudio or the free Ladybug Tools. All of these are for comparing options; once the design is fixed an engineer should build a detailed model in IES VE, DesignBuilder, Tas or OpenStudio.
Certification: Energy, Sustainability & Building Performance Analysis
What is the difference between an energy model and a life-cycle assessment?
An energy model (IES VE, DesignBuilder, EnergyPlus) predicts operational performance: heating, cooling, lighting, comfort and the resulting operational carbon. A life-cycle assessment (One Click LCA, Tally, EC3) quantifies embodied impacts from materials over stages such as production, construction, use and end of life, following EN 15978. Whole-life carbon combines both, which is why Autodesk Insight now shows operational and embodied results together.
Certification: Energy, Sustainability & Building Performance Analysis
How should I model in Revit or Archicad so the energy export works first time?
Place a room or space in every enclosed area and make sure walls, floors and roofs are room-bounding. Avoid overlapping or unenclosed rooms, keep levels consistent and model curtain walls and windows as actual openings. Use the authoring tool's energy settings to define analysis mode and building type, then export gbXML or use a plug-in such as Pollination. Note that Archicad's built-in Energy Evaluation and Vectorworks' Energos give quick in-tool checks before the handover.
Certification: Energy, Sustainability & Building Performance Analysis
What professional certifications exist for building energy modellers?
ASHRAE's Building Energy Modeling Professional (BEMP) is an ANSI-accredited certification covering modelling with the full range of physics and interpreting software results. In the UK, the CIBSE Low Carbon Consultant register covers Part L compliance work. Software vendors add their own accreditations, notably IES VE Accreditation, DesignBuilder's DSM exams and EDSL's Tas accreditation. Passive House designers use the Certified Passive House Designer exam based on PHPP.
Certification: Energy, Sustainability & Building Performance Analysis
Where does performance analysis fit in an ISO 19650 information delivery plan?
Treat each analysis model as an information container with its own purpose, level of information need and delivery milestone in the task information delivery plan. Define who exports the analytical model, which format (gbXML, IFC, HBJSON) is used, and which BIM model version it is derived from, so results can be traced. Record simulation assumptions as metadata and issue reports through the common data environment like any other deliverable.
Certification: Energy, Sustainability & Building Performance Analysis
How can a firm automate hundreds of design variants for energy and carbon?
Use a scriptable engine and a parametric front end: Honeybee or Pollination to build HBJSON models from Rhino or Revit, OpenStudio Measures to apply variants, and EnergyPlus running in parallel on a server or Pollination Cloud. Results can be written to CSV or a database and visualised in dashboards. For embodied carbon, use the One Click LCA API or EC3's openEPD API to pull factors programmatically. Keep the geometry source of truth in BIM and generate the analytical models rather than editing them by hand.
Certification: Energy, Sustainability & Building Performance Analysis
My gbXML export imports with missing surfaces or wrong adjacencies. What is the usual cause?
Almost always geometry, not the file. Rooms that are not fully enclosed, walls that are not room-bounding, gaps between floor slabs and walls, or duplicate overlapping elements produce open shells and sliver surfaces. Fix the BIM model first, regenerate the energy analytical model and re-export. If the model is legacy or too detailed, run it through Pollination's Revit plug-in or rebuild a simplified thermal model; a simpler correct model beats a detailed broken one for simulation.
Certification: Energy, Sustainability & Building Performance Analysis
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About this database
Product names are trademarks of their respective owners. Facts are verified against vendor documentation and dated sources; pricing is described by model only. Spotted an error or a missing tool? Write to [email protected] and we will correct it. Database updated: 2026-09-15.