CIBSE Design Summer Year and Test Reference Year Weather Data Now Available in Trimble’s Sefaira Building Analysis Software

October 9, 2018 Sumele Aruofor
CIBSE Design Summer Year and Test Reference Year Weather Data Now Available in Trimble’s Sefaira Building Analysis Software

SUNNYVALE, Calif., Oct. 5, 2018—Trimble (NASDAQ: TRMB) and the Chartered Institution of Building Services Engineers (CIBSE) announced today that CIBSE’s industry-standard Design Summer Year (DSY) and Test Reference Year (TRY) weather information is now available in Sefaira’s building analysis products. The implementation unlocks greater opportunities for high-quality building performance analysis and dynamic thermal modeling, which are required for all new projects in the UK to fulfill TM49 – (Design Summer Years for London) guidelines. The guidelines enable designers to analyze the summer performance of their buildings and investigate the impact of urban macroclimatic factors and climate change when carrying out overheating risk assessments for buildings in London.

Sefaira’s Software-as-a-Service (SaaS) solution enables architects and building engineers to create designs that use less energy, have better occupant comfort, use natural daylight effectively, and have appropriately-sized heating, ventilation, and air conditioning (HVAC) systems. It is becoming more evident within the Architecture, Engineering, and Construction (AEC) industry that building analysis has to start early in the project and continue until all the major decisions are made. This ensures that the design reflects the aesthetic choices of the architect and client while performing as planned.

The UK’s Buildings Research Establishment (BRE) in its “Overheating in Dwellings” guidance document predicts that temperate Northern European countries will experience an increase of extreme weather events, including heat waves. To respond to climatic conditions, architects and building designers need accurate weather data to perform rigorous analysis on their design ideas, early and often.


“CIBSE has an established reputation in the UK for providing the industry standard for weather data,” said Hugh McEvoy, director of product management for Trimble’s Sefaira solutions. “By providing our UK customers access to CIBSE weather data, we are enabling them to design better buildings, and increase their confidence in the performance analysis results that Sefaira gives them.”

Rowan Crowley, managing director of CIBSE Services, “The collaboration between CIBSE and Trimble demonstrates a new chapter in the ways in which CIBSE data can be used and accessed. Our weather data has long been trusted as the authoritative source for building performance analytics. We believe that making it available through platforms like Sefaira contributes to moving performance analytics forward.”


Sefaira users now have access to CIBSE’s weather files without the need to independently purchase, upload or update their own weather files. Sefaira users can also continue to use their own weather files. For more information on Sefaira, visit:


CIBSE publishes Guidance and Codes which provide best practice advice and are internationally recognized as authoritative design guidance for building services. The CIBSE Knowledge Portal, which makes Guidance available online to all CIBSE members, is the leading systematic engineering resource for the building services sector. For more information about the institution please visit:

About the Author

Sumele Aruofor

Sumele contributes architecture and performance-focused content to the SketchUp blogs. When she's not writing or practicing architecture, she can be found singing, cooking up a storm, or with her head stuck in a book.

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