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Low Energy Buildings – Transforming HVAC Design to an Art

posted Jul 12, 2020, 6:08 AM by   [ updated Jul 12, 2020, 6:35 AM ]

Painstakingly forging three hundred layers of steel. That is what it takes to create Damascus steel that exhibits legendary hardness, ease of sharpening and the characteristic patterned banding that gives Damascus steel its beauty. It is extreme craftmanship only possible with attention to detail.

Low energy buildings share similarities. As a prerequisite towards net-zero and carbon neutral buildings, low energy buildings embody attention to detail, and a minimalist design elegance that can only emerge through application of a whole-systems approach to optimize the overall design. Amory Lovins [1] referred to this in a 2005 Scientific American article titled ‘More Profit with Less Carbon’ as: 

“Good design should rely on optimizing the whole building for multiple benefits rather than the use of isolated components. This is not rocket science; it’s just good Victorian Engineering rediscovered”

As we know, this whole building design concept refers to the integrated design process (IDP) or integrated building design (IBD) that focuses on systematic load minimization that can only be achieved via a true interdisciplinary team effort that starts at the conceptual design stage.

Today, climate change and the increasing frequency and intensity of extreme weather is fueling a demand for climate adaptable and resilient buildings. Low energy buildings exhibit such attributes because they exploit the symbiosis that exists between a building envelope and a building’s mechanical system that, taken to an extreme, can border on nothing less than transformational wizardry.

Imagine a new high-rise office building shaped in an elegant, post-modernist or classical revival style. Such styles emphasize mass and less glass over the more ubiquitous all-glass International Style that is finally being recognized as incompatible with today’s sustainable buildings.[2] [3]

Our low energy building would exhibit recessed punched windows with a window-to-wall ratio (WWR) under 30% that is below the maximum ASHRAE 90.1 or the 2017 NECB values. In a heating dominated climate like Ottawa or Montreal, the building would incorporate high performance glazing systems and a highly insulated envelope with the far-reaching and unconventional goal to eliminate the need for perimeter heating. Minimal heating would still be needed, but only at peak winter design conditions and met with temperate air through an underfloor displacement ventilation system serving the building perimter.

That same envelope would also exhibit lower solar heat gains and cooling loads thanks to proper specification of low solar heat gain coefficients (SHGC). In turn, these features would allow selection of small, semi-passive ventilation systems based on dedicated-outdoor air systems (DOAS) plus passive chilled beams, resulting in an unobtrusive and minimalist design. Gone would be the ubiquitous all-air ventilation systems with ceiling diffusers present everywhere and served by large air handling systems. To be sure, such a design would be a paradigm shift in North American design practices, but needed in the face of escalating climate change urgency.

Beyond the lower operating cost, lower carbon footprint and minimalist elegance of such a design, there would be countless benefits not readily apparent including: increased comfort afforded by the warmer surface temperatures of exterior walls in winter and lower heat gain in summer; superior air quality and removal of contaminants via the displacement ventilation system; more moderate lighting levels and less glare near the building perimeter thanks to the smaller glazing which would unexpectedly and surprisingly, result in a higher amount of daylight since blinds would likely stay up.

 All in all, a design that subscribes to the old maxim that “less is often more” and the notion that simplicity leads to good design, or as Leonardo da Vinci said:

"Simplicity is the Ultimate Sophistication"

[1] Lovins, A. “More Profit with Less Carbon”. Scientific American, September 2005. Accessed at:

[2] It’s time to Rethink the All-Glass Building. Accessed at:

[3] Are architects turning their backs on glass skyscrapers?. Accessed at: