EDSL

What EDSL does

EDSL (Environmental Design Solutions Limited) is a UK-based private software company headquartered in Stony Stratford, Milton Keynes, founded in 1988. It develops and distributes Tas, an integrated building performance simulation suite used for hourly dynamic thermal modeling, HVAC system design, daylight analysis, and regulatory compliance reporting. The Tas platform comprises four core applications — Tas 3D (geometry creation/import), TBD (Building Simulator), TSD (Results Viewer), and TPD (Tas Systems for HVAC plant modeling) — supplemented by specialized utilities including the TM59 Wizard for domestic overheating, the 90.1 Wizard for ASHRAE 90.1 compliance, the UK Building Regulations Studio, Climate Based Daylight Modelling (CBDM), Design Day Wizard, TasGenOpt for parametric optimization, and Ambiens 2D for CFD. The software integrates with EnergyPlus (IDF), Revit (gbXML), MEPWorx, DWG, and DOE-2, and is validated against BS EN ISO standards 13791, 13792, 15255, and 15265.

The company serves a fragmented professional user base of building engineers, energy consultants, and compliance specialists across the UK, EU, and US. Revenue is generated through four streams: software licensing (annual subscriptions sold via three multi-currency online storefronts in GBP, EUR, and USD, with both dongle and dongle-less options), discounted student licenses, professional consultancy services (BRUKLs, EPCs, overheating analysis, HVAC modeling, daylight analysis, LEED, BREEAM), and paid training courses. Go-to-market is primarily direct and self-serve — free trials, free online e-training, and own-storefront e-commerce — supplemented by content marketing via blog and documentation, and social channels (LinkedIn, Twitter/X).

The business is small (11–50 employees), privately held with no disclosed investors, parent, or subsidiaries. Recent strategic activity has centered on product expansion (TM59 Wizard, Approved Document O aperture function, BB101 2016 report, ASHRAE 90.1 multi-version support), pricing-model innovation (dongle-less digital licenses in 2022), and PLG channel expansion (free e-training portal in 2022), with sustained software release cadence culminating in v9.5.7 in February 2026.

Name

EDSL

Legal name

Environmental Design Solutions Limited

Website

https://edsl.net

Company type

Private

Founded year

1988

Operating status

Operating

Headcount range

11–50 employees

Short description

EDSL (Environmental Design Solutions Limited) is a UK-based private software company that develops Tas, an integrated building thermal simulation and compliance suite used by engineers, consultants, and compliance professionals across the UK, EU, and US for energy modeling, HVAC design, daylight analysis, and building regulations reporting.

Ownership category

akta.pro rank

Headquarters

HQ city

Milton Keynes

HQ country

United Kingdom

HQ region

Europe

Offices1 record

Markets served

GTM type

B2B

Offering type

Software

Cost components

Personnel, Technology or R&D, Operations, Marketing or Sales, Infrastructure

Revenue model

1. Software Licensing: Tas software is sold as licenses with options for dongle-based and digital (dongleless) licenses. The company operates online shops in GBP, Euro, and USD currencies for license purchases.
2. Student Licenses: Tas software is available for students at reduced pricing through dedicated student licensing.
3. Consultancy Services: Professional consultancy services for L2A BRUKLs, EPCs, overheating analysis, HVAC systems modelling, daylight analysis, LEED, and BREEAM assessments.
4. Training Services: Paid training courses including Tas Engineering Course, Introduction to Systems, Accreditation Process, and Revit gbXML Training.

Pricing tiers

Go-to-market motion1 record

Distribution channels5 records

Marketing channels6 records

Core offering

EDSL develops, sells, and supports Tas, an integrated building performance simulation software suite that performs hourly dynamic thermal modelling, HVAC plant simulation, 2D CFD airflow analysis, and climate-based daylight modelling for buildings of any size or complexity. The suite is packaged as Tas Engineering and includes purpose-built compliance studios for UK Building Regulations (Part L, EPCs, BRUKL), ASHRAE 90.1 Appendix G, CIBSE TM59/TM52, BB101, LEED, and BREEAM. In addition to software licensing, EDSL provides paid consultancy services and structured training courses to building engineers, energy consultants, and compliance professionals.

Product overview

EDSL offers Tas, an integrated building performance simulation software suite consisting of multiple interconnected modules. The core platform is Tas Engineering, which provides hourly dynamic thermal simulation for buildings. The suite is built around four main applications: Tas 3D (T3D) for geometry creation and import, Tas Building Simulator (TBD) for assigning constructions and running simulations, Tas Results Viewer (TSD) for viewing results, and Tas Systems (TPD) for HVAC plant modelling. Additional utilities include the TM59 Wizard for domestic overheating analysis (TM59/Approved Document O), the 90.1 Wizard (TPDx) for ASHRAE 90.1 compliance, UK Building Regulations Studio for Part L/EPC/BREEAM, Climate Based Daylight Modelling (CBDM) for daylight analysis, Design Day Wizard for load calculations, and Ambiens 2D (TAI) for 2D CFD. Tas integrates with EnergyPlus (IDF), Revit (gbXML), MEPWorx, DWG, and DOE-2 for interoperability.

Differentiator

Problem solved

Functional benefit

Brands

• Tas Engineering: Building thermal simulation and modeling software
• Tas Systems
• Tas 3D
• TBD (Building Simulator)
• TSD (Results Viewer)
• TPD (Tas Systems)
• Tas CFD (Ambiens)
• TM59 Wizard
• 90.1 Wizard
• UK Building Regulations Studio 2021
• Design Day Wizard
• CBDM (Climate Based Daylight Modelling)

Products and services

• Tas Engineering (v9.5.7) Industry-leading integrated building modelling and thermal simulation software suite that performs hourly dynamic thermal simulation for buildings of any size or complexity. Includes Tas 3D (geometry), Tas Building Simulator, Tas Results Viewer, Tas Systems (HVAC plant modelling), Ambiens 2D (CFD), and dedicated compliance utilities (TM59 Wizard, 90.1 Wizard, UK Building Regulations Studio, CBDM, Design Day Wizard). Targeted at building engineers, energy consultants, and compliance professionals. Sold as annual subscription licenses with dongle and dongleless digital options.
• EDSL Consultancy Services Professional consultancy services delivered by expert users of the Tas software, covering L2A BRUKLs, EPCs, overheating analysis, HVAC systems modelling, daylight analysis, LEED, and BREEAM assessments. Targeted at clients who need outsourced building performance analysis or compliance deliverables.
• EDSL Training Courses Paid training courses including the Tas Engineering Course, Introduction to Systems, Accreditation Process, and Revit gbXML Training, aimed at building engineers and consultants needing to become proficient with the Tas suite.

Quantifiable outcome

• Validated against BS EN ISO Standards 13791, 13792, 15255, and 15265 - results fall within specified margins of expected results

Segments4 records

Ideal customer profiles4 records

Technology focussed Yes

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Integration5 records

AI capability3 records

Feature10 records

Scale indicators1 record

Recent moves6 records

Expansion highlights6 records

Broad incumbents

• Bentley Systems: Bentley Systems offers OpenBuildings and integrated energy/environmental analysis within its iTwin platform, serving building designers, engineers, and infrastructure owners. It competes with EDSL by offering building performance as part of a broader digital-twin ecosystem rather than as a specialized simulation tool.
• Autodesk: Autodesk, through Revit, Insight, Green Building Studio, and the Forma platform, offers integrated energy and environmental analysis capabilities inside its dominant BIM authoring tools. As a broad AEC incumbent, Autodesk competes with Tas both directly (Insight/Forma energy analysis) and indirectly by owning the upstream BIM geometry that flows into Tas via gbXML.
• Nemetschek Group (Graphisoft): Nemetschek, the parent of Graphisoft (ArchiCAD) and Solibri, is a broad AEC software incumbent. Through ArchiCAD and the Nemetschek Group ecosystem, it competes with EDSL for architects' attention on energy/environmental design while bundling it into a wider building design portfolio.

Direct peers

• DesignBuilder Software: DesignBuilder is a UK-based building performance simulation company whose flagship product wraps the EnergyPlus engine in a user-friendly interface for thermal, energy, daylight, and HVAC analysis. It competes head-to-head with Tas in UK Part L, ASHRAE 90.1, and LEED/BREEAM compliance workflows, serving the same engineer/consultant buyer.
• Integrated Environmental Solutions (IES): IES is the most direct competitor to EDSL, offering the Integrated Environmental Solutions Virtual Environment (IESVE) for dynamic thermal simulation, HVAC, daylight, and energy compliance across UK, EU, and US standards. Both companies target building engineers and consultants with comparable prepackaged simulation suites and overlapping compliance studio offerings.
• Sefaira (Trimble): Sefaira, now part of Trimble, is a building performance design tool focused on early-stage energy and daylight analysis for architects. It overlaps with Tas's climate-based daylight modelling and conceptual energy analysis use cases, and competes for the architect/engineer persona at the front end of building design.

Emerging players

• Pollination: Pollination, founded by the creators of the Ladybug Tools suite, provides Rhino/Grasshopper-based environmental design and simulation software. It overlaps with Tas in daylight, energy, and comfort analysis but is positioned for the parametric/Grasshopper workflow niche, making it a partial-overlap emerging peer.
• cove.tool: cove.tool is a cloud-based building performance analysis and optimization platform targeting architects and developers for early-stage design decisions. It represents the cloud-native, modern-UX approach that EDSL's on-premise Tas would be benchmarked against, with partial overlap in energy modeling and daylighting.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat4 records

Key risks6 records

Key highlights7 records

Customer concentration

• Xx.com/edsltas
• LinkedInlinkedin.com/company/edsl-environmental-design-solutions-ltd-
• Facebookfacebook.com/pages/category/Software-Company/EDSL-Tas-102645415010886

Compliance4 records

Revenue estimate

Valuation estimate

Number of profiles

Funding overview

Funding rounds

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about EDSL