Engineering better energy performance since 1990
For more than 35 years, Demand Side Energy has helped commercial, industrial, institutional, and public-sector organizations reduce energy costs, improve building performance, and advance sustainability goals through practical engineering expertise.
From energy audits and commissioning to carbon management and RETScreen modelling, we help clients make confident decisions backed by data.
35+
Years of Technical Experience
1250+
Energy Efficency Projects
100+
Satisfied clients
Built on Practical Engineering Experience
Demand Side Energy was founded by Alex Fleming, P.Eng., CMVP, with a focus on helping organizations make better energy decisions through technical analysis, performance verification, and practical implementation.
Over the past three decades, the company has worked with industrial facilities, commercial buildings, educational institutions, utilities, and government organizations to identify opportunities, validate performance, and reduce operating costs.
Today, Demand Side Energy combines engineering expertise with modern energy modelling, carbon analysis, commissioning, and RETScreen methodologies to support organizations pursuing efficiency and net-zero goals.
Technical Leadership
A small, experienced team bringing engineering, sustainability, and energy systems expertise to complex building performance challenges.
Alex Fleming
Principal Engineer
P.Eng, CMVP
Founded Demand Side Energy in 1990 and has led energy efficiency initiatives across commercial, industrial, and institutional sectors. Alex brings extensive experience in audits, commissioning, DSM programs, energy performance analysis, and third-party engineering review.
Andrew Fleming
Manager, Sustainability
MA, CEM, CEA
Leads commissioning and sustainability projects ranging from office buildings to major public-sector facilities. Andrew specializes in building performance, HVAC systems, energy modelling, and operational optimization.
Ndu (Mack) Onwukeme
Manager, Energy Systems
M.Eng, CET
Provides multidisciplinary engineering coordination and energy systems expertise across power, building utility, telecommunications, oil and gas, and infrastructure projects.
Selected Project Experience
A cross-section of energy modelling, commissioning, RETScreen, and sustainability projects delivered across public, institutional, and commercial facilities.
RETScreen
Energy Modelling
Commercial Real Estate
Office buildings, retail developments, mixed-use facilities, and commercial portfolios requiring energy audits, commissioning, carbon modelling, and building performance optimization.
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RETScreen
Energy Modelling
Municipalities & Public Institutions
Recreation centres, civic buildings, libraries, water and wastewater facilities, and municipal energy management programs supporting operational efficiency and long-term capital planning.
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Ready to Improve Building Performance?
Whether you are planning a retrofit, pursuing net-zero targets, or looking for trusted engineering guidance, Demand Side Energy can help you move forward with confidence.