In Vancouver single family housing is demolished to make bigger new houses, often of the same style. Yet, in this study to be published in July by University of British Columbia researchers and MountainMath Software, the perception that new is greener and better is seriously challenged.
UBC Reports notes that, “despite the better energy performance of the new homes, this cycle is likely to increase overall greenhouse gas emissions.”
Even though the City of Vancouver has a Zero Emissions Building Plan which was supposed to eliminate emissions from new building by 2030, “the teardown cycle is preventing many single-family homes from surviving long enough to ‘pay back’ the initial impacts caused by construction materials, which are not accounted for in the current plan.”
The construction of new single family residences “will result in one to three million tonnes of added emissions between 2017-2050, even though the new homes will require less energy to heat and operate. It also reports that each percentage point increase in land value will result in an additional 130,000 tonnes of emissions in Vancouver during the same period.”
Jens Von Bergmann of MountainMath Software nails down the policy approach to alleviating this problem. While it will take 168 years for efficiency gains to recover construction impacts, this teardown cycle will cause emission to increase, “unless we change residential zoning to permit denser forms of housing.”
Higher density housing forms will last longer than the single family houses they replace and provide environmental benefits sooner. Study co-author Joseph Dahman observed that low to mid-rise housing, “increases overall housing stock, addresses affordability and creates a more vibrant public realm” .
And thanks to this study, we know that density is greener too.
Images Vancouver Sun and Globe and Mail
May 25, 2018