Today’s new high-performance commercial and institutional buildings can access construction technology delivering vastly superior levels of energy efficiency versus buildings built in past decades.
Going forward, they may have little choice but to improve. Carbon reduction goals and objectives have been established across many jurisdictions, resulting in regulatory pressure on owners. Municipal regulations in cities like Vancouver and New York will soon begin penalizing buildings, both new and old, that fail to reduce their carbon emissions.
For example, Vancouver’s Annual Greenhouse Gas and Energy Limits bylaw targets a 50 per cent reduction in construction-related embodied carbon by 2030, and 100 per cent by 2050. Owners of larger properties must start reporting their emissions this June, with fines assessed at $350 per tonne of CO2 for those exceeding preset allowable limits. Separately, the Vancouver building bylaw now mandates the assessment and reduction of embodied carbon in new construction.
An estimated 50 per cent of today’s buildings could be still standing by 2050. Owners may be faced with the choice to either tear down and replace them or retrofit existing structures.
A persuasive business and environmental case for retrofitting and repurposing existing buildings has developed alongside the awareness of the high levels of embodied carbon associated with new construction.
“While the carbon payback of new construction and retrofits can vary greatly depending on building type, location, climate and grid mix, retrofitting a building generally saves 50 to 75 per cent of embodied carbon,” according the Institute of Market Transformation.
Operational carbon savings over a building’s lifespan add up as well. When viewed in combination with the reduced embodied carbon benefits of retrofitting, the importance of these savings becomes clear.
Robin Lucidarme, business automation engineer with energy engineering firm Sustainable Project Group, says new modern buildings can reduce operational emissions by one half versus an existing building. However, retrofitting an existing building can potentially lower emissions by nearly 85 per cent.
Façades are a good place to start. They are the building’s outer skin and are fundamental to overall carbon reduction efforts since all operational functions occur inside that skin.
During a recent presentation made in conjunction with Canadian high-performance façade manufacturer GlasCurtain, Lucidarme explained how investments in the latest façade technologies, if made today, can lower emissions, reduce maintenance, and improve net present value and ROI over a building’s lifespan.
Replacing façades have been recognized in the past as providing other key benefits to owners as well, many relating to market expectations.
WZMH Architects outline in their recently-released Recladding Guide how an office tower might lose its lustre a few decades after construction, sending tenants towards “gleaming, green-certified new buildings.”
More recently, conversations with their clients have shifted.
“Now ‘net-zero’ and ‘carbon’ are often words that kick-start the conversation.”
WZMH explains each prospective façade retrofit begins with an investigation of the building’s core structure to determine how recladding can best be undertaken. From there, a number of options come forward that combine energy-efficiency objectives with esthetics, both from street level and occupant viewpoints.
Peter Dushenski, managing director of GlasCurtain, explained how high-performance building façades go beyond improving energy efficiency performance and meeting regulatory requirements. Enhanced occupant health and well-being resulting from improved outward visibility, and increased interior natural light, are also critically important.
“Buildings should enhance our living experience.”
GlasCurtain uses fibreglass framing exclusively. This reduces thermal bridging up to 99 per cent compared to typical aluminum or steel framing systems.
In fact, the company’s Thermaframe9-ph curtainwall is, “the best thermally-performing curtain wall in the world.”
Returning to the matter of embodied carbons, research by UBC confirms that, compared to aluminum, fiberglass framing can also contribute to the reduction of the embodied carbon associated with a building.
As Dushenski explained, this is due to reduced energy requirements during fibreglass manufacturing.
Duschenski made an interesting observation. As higher performance buildings are built or retrofitted, the proportion of embodied carbon is beginning to outweigh operational carbons, a reverse of the current relationship, but with measurable reduction improvements in both.
John Bleasby is a Coldwater, Ont.-based freelance writer. Send comments and Climate and Construction column ideas to editor@dailycommercialnews.com.
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