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About Us

Purpose Building is an employee-owned enterprise created to accelerate real estate to Planet-Positive Performance. We deliver strategies and designs that create physically and financially healthy facilities that fit a circular, low-carbon economy. Founded by leaders from the green building team at Halsall Associates, we focus on collaborative service excellence for Owners, Managers, Designers and Builders seeking to achieve the next level of performance.

We operate with total commitment to Team Success, Technical Excellence, Honesty and Social Responsibility.


Creative: Integrate wisdom from multiple perspectives to develop leading edge strategies that accelerate progress for New Build, Retrofit and Operational Improvement.

Pragmatic: Apply acute market awareness, reliable data and deep technical experience to know what works, and what doesn’t, when going to the next level across all asset classes.

Focused: Align solutions with our client’s sustainability aspirations by thoroughly understanding their targets, processes and structure.

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Our Role

We fit our role to the challenges you face. We can provide sustainability strategy and design support to your project team, support creative procurement processes and/or deliver integrated project design services through collaborative team management. We always start by applying deep, diverse knowledge to define and meet your specific needs.



Our Team

A dynamic team using high-performance collaboration
to create a better future for society.


Douglas Webber, P.Eng, LEED AP

Doug has focused on creating high performance buildings for over 25 years. After general contracting and building off-grid demonstration homes, he joined Halsall in 1999. He led Halsall’s Green Planning and Design practice to become a national team serving new and existing building markets Following WSP’s acquisition of Halsall, Doug led WSP Canada’s Sustainability and Energy business line. He has delivered performance modeling, certification services, retro-commissioning and portfolio performance management across all asset classes, at all scales and all phases of asset life. He is Chair of the CaGBC’s newly formed Zero Carbon Steering Committee. Doug was recognized as one of Canada’s Clean 50 in 2013.


Eric Chisholm, P.Eng., CEM, LEED AP

Eric has been providing strategic direction and technical solutions to sustainability and energy management for over 10 years. He most recently served in the role of Manager of National Energy Performance, Sustainability & Energy at WSP. His experience delivering carbon reduction strategies, portfolio planning, energy audits, retro-commissioning, and LEED certification has supported hundreds of individual properties across Canada and portfolios representing tens of thousands of properties. Eric was named an Emerging Leader in Canada’s 2016 Clean50.

Luka Matutinovic, P.Eng., CPHC, LEED AP BD+C

Luka has spent 13 years working with the other Purpose Building Principals improving the performance of the built environment. He combines detailed knowledge of building design, operations and project delivery, and thrives on making advanced technical solutions possible. To achieve this, he focuses on integrating performance analytics into the design process to improve how people work together. The result is elevated value-creation at the project, team and organizational levels. Luka has acted as the sustainable design lead on over 100 projects in nearly all asset classes, including LEED Platinum, Passive House and Zero Carbon projects.



Peter Halsall, P.Eng, MASc

Peter excels at driving change; developing commitment and finding innovative solutions within existing supply chains and financial models. As Chairman/CEO of the Halsall group of companies, Peter led the integration of sustainability into all aspects of the businesses and services through growth to over 350 people. After Halsall’s sale to an international company, he was responsible for creating the company's global sustainability program. Most recently, at the Canadian Urban Institute, he led the development of Solutions for a Low Carbon Future. He has been recognized with Lifetime Achievement Awards by CaGBC and the Canada Building Envelope Council.


Stacy (Xi) Sun, MASc, BES, LEED GA

Stacy is an experienced building performance analyst. She is focused on integrating performance analytics - including energy, daylighting and thermal comfort - into the design process. Stacy holds a Master’s degree in Building Science and a Bachelors in Environment & Business. Before Purpose Building, she worked at WSP in Toronto and Transsolar in New York. Since 2013, she has volunteered with the CaGBC Toronto Chapter including the Emerging Green Professionals Committee. In 2018, she was recognized for her dedicated efforts as a finalist for CaGBC Ontario Volunteer Leadership Award.


Matthew Hirsch, B.A.Sc., LEED AP O+M

Matthew has nearly 10 years of experience developing practical sustainability solutions for some of Canada’s largest commercial office developments and multi-unit residential communities. He focuses on meeting each client’s particular sustainability targets through all stages of the journey. He has experience in building performance benchmarking and auditing on all  scales of projects, and has been involved with over 50 LEED projects. Matthew brings an interdisciplinary background and experience, and uses this to take a collaborative approach to understand complex problems, distill clear actions and empower clients with the strategies and tools they need to achieve their desired outcomes.


Daniele Magditsch, M.A.Sc., B.Sc., LEED AP O+M

Daniele has been providing sustainability and energy consulting for over 6 years. She has managed projects pursuing LEED, BOMA BEST, WELL, and TGS, among other sustainability certifications.  With degrees in  Environmental Biology and Environmental Applied Science, Daniele brings a passion for improving the relationship between the natural and built environments., Daniele worked with the Principals of Purpose Building for 4 years prior to joining Purpose Building and was a third-party Toronto Green Standard Evaluator for the City of Toronto.


Kristen Jaczko, M.A.Sc., LEED Green Assoc.

Kristen is a building performance analyst with a passion for improving the built environment, focusing on energy management. Her experience includes supporting sustainability certifications, existing building energy management and new construction performance analysis. While an undergraduate in Mechanical Engineering, she was part the Queen’s University team that participated in the 2013 US Solar Decathlon to design and build a solar-powered house. She completed her Master’s thesis in 2017 on Integrated Energy Systems for High Performance Building.


Elmira Reisi, M.Sc., B.A.Sc.

Elmira is a building performance analyst with global experience in delivering energy modelling, energy audits, renewable energy solutions and custom tools to evaluate outdoor thermal comfort conditions. Her focus is developing exceptionally comfortable, healthy, low-energy environments for occupants. Elmira graduated from Engineering Science at the University of Toronto where she was also deeply involved in Engineers Without Borders. She earned her Master’s in Building Technology and Climate Responsive Design at the Technical University of Munich. Prior to joining Purpose Elmira worked at Transsolar in Stuttgart and IESC in Toronto.


Emma Rohmann, P.Eng., LEED AP

Strategic Partner

Emma has over a decade of experience in green building and community design, construction, and operation. As project manager at Halsall, she led multi-disciplinary teams with a focus on existing building and community-scale projects. She was a key team member on award-winning projects that include Waterfront Toronto's Minimum Green Building Requirements and Evergreen Brickworks. Over the past 3 years, Emma has leveraged her environmental engineering and green building experience to focus on achieving indoor spaces that support long-term health. She has created engagement and wellness materials for GM Canada, Toyota Canada, and is a sought-after speaker on environmental health and green living. 

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What We Do


Sustainability Strategy

Achieving better-than-industry performance requires having a team committed to better outcomes and knowing where to shift the supply chain. To create this focus, we:

  • Benchmark leading solutions for managing carbon, energy, health factors, durability and materials

  • Implement practical measurement, tracking and reporting processes that align with client processes.

  • Communicate targets, solutions and outcomes that inspire stakeholders and the broader market

We combine extensive knowledge from existing facility performance evaluation and new development design and construction review.

Performance Analysis

Properly applying the appropriate metrics and tools ensures you achieve the desired performance over the appropriate timeframe. To establish the outcomes, build commitment and remove barriers through planning and design, we:

  • Define performance targets based on predictive modelling and experience with existing building operations and economics 

  • Develop design solutions using energy, daylight and thermal modelling and parametric, generative algorithms

  • Provide guidance to keep project teams focussed and on schedule.


Asset Improvement

Sustainability performance is increasingly important for even gracefully aging real estate assets. To achieve the full potential of a facility through each stage of planning and implementation, we:

  • Identify and realize opportunities through Audits; Recommissioning; Tune-ups; Deep Retrofit Analysis; and advanced Energy Management services.

  • Define sustainability targets and metrics; and integrate into design, procurement and construction

  • Manage certification compliance for LEED, WELL, Energy Star, Zero Carbon Building Standard, etc.

Portfolio Programming

Maximizing portfolio value involves identifying the best opportunities for performance improvement and optimizing implementation. We develop solutions through:

  • Management process design to align portfolios with sustainability mandates

  • Strategies to (re)position assets, engage stakeholders and confirm success through rating systems

  • Technical support to operationalize and implement selected strategies

  • Performance measurement and communication to make success clear to different audiences.

Contact Us

119 Spadina Avenue, Suite 600, Toronto, ON M5V 2L1 | 416-613-9113

Apply to be a member of the team


If you have some skills in performance analysis and design for new and existing facilities but want to accelerate your learning, we have the mentors for the next phase of your learning journey. If you think Purpose Building is where you can apply your talents to make a difference, learn more about the opportunity.

If you are an experienced professional seeking to have greater impact on the performance of the built environment, we are always seeking to add great people who will enhance our ability to deliver on our mission. Feel free to contact us about your career aspirations.


Submit a letter and CV that demonstrate your interest, fit and capability, to careers@purposebuilding.ca


Why you are looking. What attracts you to Purpose. What role you would like to have, and why. An example of a career accomplishment and an activity outside your career that demonstrate how you would help us achieve our mission. When you could start. How we reach you.


If we see the potential for a good fit, we will contact you for a discussion.