About Us

Serving the building simulation community for over 30 years

Environmental Design Solutions Limited (EDSL)

Environmental Design Solutions Limited (EDSL) was formed in 1989 to commercially develop Tas Software. EDSL sells Tas software and consultancy services using Tas. EDSL believe that the mixing of development, consultancy and software support leads to a focused software product, with quality support available to end users.


EDSL USA Inc. was formed in 2017 to bring Tas to the North American market. Being located in midtown Manhattan has enabled EDSL to grow its presence in local and worldwide  communities. EDSL USA’s mission is to serve designers, engineers, and sustainability specialists through continually-improving software and responsive support.

Tas: Fast and Robust Building Simulation Software

Tas is a complete solution for the simulation and thermal analysis of buildings. It is built to create building models for simulation, perform climate-based daylight modeling analysis, perform design sizing calculations, and calculate energy consumption, CO2, and cost information. Tas allows users to visualize building simulation data in 2D and 3D with presentation-quality graphics.