Leading global innovator of sustainable analysis technology

Resource-efficient, healthy and cost-effective built-environments

About IES

Over the last 25 years we have built a solid reputation as the leading global innovator in integrated performance based analysis, and we're now home to the largest building physics analytics team in the world.

Supporting resource-efficient, healthy and cost-effective built-environments, we simulate and analyse data to give those involved in their creation and management the information needed to make smarter, more sustainable decisions with confidence.
Our unique software and technology, is supported by expert consultancy. And our dedicated R&D department ensures our analytical tools and industry knowledge stays pioneering and innovative.

Our Mission

Better Buildings: Smarter Cities

We believe that every building of every city in the world can be decarbonised. Our purpose is developing the technology to make that happen. Our ultimate aim is to create a built environment that is resource and energy efficient. Eliminating global reliance on fossil fuels while promoting comfort, health and wellbeing, and fairer access to energy for every citizen in the world.

Our History

IES was founded on three fundamental observations.

1. Buildings are major consumers of energy and must be made more efficient to cut CO2 emissions, conserve fossil fuels and preserve the environment for future generations.

2. Historically buildings were generally designed on experience and simplistic performance calculations, even though performance-based building simulation had been proven to create buildings that consume significantly less energy.

3. Such building performance tools were too complex and remained in the hands of academics, making little impact on mainstream commercial design.

Meet our Directors

Don McLean

Founder and Managing Director (CEO)

Don is as passionate as it gets about building simulation and was recognised as a Star of Building Science by Building for Change in 2013. He’s dedicated the last 40 years of his life to pioneering and developing performance simulation tools that significantly improve the building design process. Don’s vision and leadership has been the driving force behind the success of IES, seeing the company grow from humble beginnings to a successful and key global player in the field of sustainable building design and operation.

Craig Wheatley

Chief Technology Officer

With over 20 years’ industry experience, IBPSA Fellow Craig is a true expert in Environmental Engineering. His technical expertise and enthusiasm combine in a commitment to transforming the way buildings are designed, built and operated. By staying alert to industry issues, Craig ensures that the commercial needs of the building simulation community continue to be met by IES’ technology, while his proactive approach has seen him form close ties with various governmental, academic and industry partners to technically evolve and further the adoption of performance analysis and regulation on an international scale.

David McEwan

Consultancy Director (Global)

David brings a wealth of engineering knowledge to the business with over 35 years’ experience in Global Building Consultancy. His considered approach to energy-efficient design has seen him act as professional adviser to a number of organisations throughout his career including The Scottish Office (Building Regulations), The Scottish Parliament, Financial Institutions, the UK’s National Health Service, Local Authorities, Manufacturers, Building Developers, Building Contractors and Universities. Under David’s guidance, the IES Global Consultancy portfolio has grown from strength to strength. His commitment to driving the industry forward means David is always keen to explore new business models with IES’ customers and partners to build new, mutually beneficial and innovative business partnerships.

Susan Falconer

Marketing Director

Susan joined IES in 1996 after graduating from the University of Strathclyde with a Degree in Marketing. Susan has been involved in all the Commercial, Financial, Administration, HRM, Sales and Marketing aspects within the company.

Susan has vast experience of creating and implementing marketing and communication strategies that have delivered consistent ROI and growth for IES. She has proven experience of using data to make insight based decisions, taking new products and services to market through innovative campaigns, and facilitating the growth of the company globally.

Scott Finlayson

Finance Director

Scott is responsible for all of IES’ financial and legal functions. An EY trained Chartered Accountant, with 20 years of post-qualifying experience working in both PLCs and growing technology companies, Scott’s meticulous approach has helped grow the business into the global success it is today, including establishing new subsidiary companies of IES in Ireland, Singapore, India and Abu Dhabi. 

Ruth Kerrigan

Chief Operating Officer

Ruth works closely with the CEO on implementing the company vision and strategy, with particular emphasis on integration with emerging and future technologies and developing new solutions for the decarbonisation of the built environment. Having worked in the R&D space for the last 20 years, Ruth has extensive experience in the areas of modern methods of construction, adaptable structures, energy efficient buildings, control systems engineering, building design and renovation, urban and master planning, energy management and integration of buildings with their resource networks. 

Rohan Rawte

Director Asia and Middle East

Rohan has been involved in the Computer Aided Engineering (CAE) industry for almost 20 years. Initially specialising in the use of digital twins for avoiding failure, extending life/warranty, and optimizing cost in the mechanical and automotive industries, Rohan transitioned from the mechanical industry to the built environment when he joined IES in 2010. Rohan now manages multiple divisions for IES across the Middle East, India and Asia. Based in Singapore, he is currently focused on developing the company’s regional HQ in Asia, drawing on his experience in facing new markets, supporting the development and sale of new products, developing global and local partnerships and fostering multi-disciplinary global teams to drive results.

Lorna Celnik

HR Director

Lorna oversees employment and recruitment matters across all staff locations globally and has supported rapid international growth, including the establishment of offices in North America, India, Singapore and the Middle East. Lorna joined IES in 2007, initially to work on a 2-year KTP (Knowledge Transfer Partnership) project, in partnership with Glasgow Caledonian University, where she gained her MSc in HR. This was the first HR KTP in Scotland and enabled IES to successfully develop HR strategy and policy, building upon the strong IES people-centric culture. Lorna is a Chartered Fellow of the CIPD and regularly guest lectures on International HRM.

Richard Fletcher

Global Sales Director

Richard has over 25 years’ experience within the construction industry, over 20 of which has been involved with the digital transformation of the built environment. Whilst holding senior roles within construction technology vendors, Richard has worked with international industry bodies, academic institutions and technology partners to progress the digitalisation of construction through close collaboration on commercial and research and development projects. Leveraging his previous experience, his prime focus within IES is to help our customers adopt our ground-breaking Digital Twin technology to help them achieve their sustainability goals.

Power Station Challenge

IES and our users have already made a significant impact on reducing the built environments carbon footprint. So far, with our technology, we have saved over 30 power stations from having to be built. We’re asking you to join us in our challenge to prevent 100 power stations.


IES is widely regarded as a world leader in intelligent sustainability solutions for the built environment. As such, IES is fully committed to carrying out all reasonably practicable measures to continually improve its own environmental performance and reduce the impact of its operations. Our biggest impacts, and therefore focuses, are our office & event operations, IT equipment use, and travel.

SME Climate Commitment

Recognising that climate change poses a threat to the economy, nature and society-at-large, IES have joined the United Nation’s Race to Zero campaign under the SME Climate Commitment. Taking action immediately in order to:

  1. Halve our greenhouse gas emissions before 2030
  2. Achieve net zero emissions before 2050
  3. Disclose our progress on a yearly basis

In doing so, we are proud to join governments, businesses, cities, regions, and universities around the world that share the same mission.



Our Customers Include:

Our Partners Include:

World Leaders

Operating in more than 13 countries around the world, across Europe, North America, Asia, Middle East, and Australia, our specialists work with a growing network of partners and associates to deliver truly valuable expertise in building analytics.

Work with us

Interested in joining our team? Visit our Careers pages to browse our current opportunities. 

Diversity and Inclusion at IES

IES employees come from a wide range of backgrounds and cultures and we firmly believe this diversity is a great asset to our company. IES values employees’ skills and performance, irrespective of age, disability, gender, relationship status, pregnancy, race, religion or sexual orientation.

IES works with organisations that help to promote a level playing field for underrepresented groups in society and we would take prompt action to address any less favourable treatment towards minority groups.

Copies of relevant company policies can be obtained from IES Human Resources: careers@iesve.com