In the sweltering heat of Pakistan’s hot-humid climate, residential buildings are often energy guzzlers, their poorly sealed envelopes and non-climate-responsive designs leading to excessive cooling loads. But a groundbreaking study led by Aamer Sajjad from Superior University Lahore is set to change that, offering a blueprint for energy-efficient, sustainable housing that could reshape the construction industry.
The research, published in the journal *Sustainable Business and Society in Emerging Economies* (translated from Urdu as *Business and Society in Emerging Economies*), focuses on a comprehensive retrofit package that combines passive design strategies with innovative materials. At the heart of this approach is Lightweight Aggregate Concrete (LWAC), a material that Sajjad and his team have rigorously tested and validated for the first time in Pakistan.
The study’s findings are nothing short of impressive. By integrating a suite of retrofits—including roof and wall insulation, reduced window-to-wall ratios, low-U double glazing, external shading, passive cooling, and enhanced cross-ventilation—the researchers achieved a staggering 60.7% reduction in Energy Use Intensity. This translates to significant commercial impacts: 38,639 kWh of avoided energy use per year, utility savings of 377,188 PKR, and a reduction of 19,320 kg of CO₂ emissions annually.
Sajjad explains, “The integrated framework not only improves thermal performance but also supports sustainable housing in hot-humid climates. It’s a win-win for both the environment and the economy.”
The LWAC samples tested in the study demonstrated remarkable properties: 15–20% lower density, approximately 48% lower thermal conductivity, and a compressive strength of at least 30 MPa. This confirms the material’s structural adequacy and enhanced thermal resistance, making it an ideal choice for envelope materials in energy-efficient buildings.
The financial implications are equally compelling. The combined retrofit and LEED v4 measures resulted in a net premium of 336,298 PKR with a simple payback period of just 0.89 years, which can be reduced to less than 0.7 years under a 6% annual tariff escalation. This rapid return on investment makes the approach highly attractive for developers and investors.
Sajjad’s research provides the first validated climate-responsive retrofit and LWAC integration framework for Pakistan’s residential sector. It demonstrates that high-performance, low-carbon housing is not only technically feasible but also cost-effective and rapidly scalable using local materials. This has significant implications for the energy sector, offering a pathway to reduce energy consumption and emissions in residential buildings.
As Pakistan and other hot-humid regions grapple with the challenges of climate change and energy efficiency, Sajjad’s work offers a beacon of hope. It provides evidence-based guidance for policymakers, designers, and developers seeking to promote sustainable construction. The study directly supports the implementation of the Energy Conservation Building Code (ECBC)-2023 and sets a precedent for future developments in the field.
In a world increasingly focused on sustainability, Sajjad’s research is a testament to the power of innovation and the potential for transformative change in the construction industry. As the sector looks to the future, this study serves as a compelling example of how energy-efficient retrofitting and innovative materials can pave the way for a more sustainable and prosperous built environment.