The Government of Québec writes about its demonstration projects which are showcasing how low carbon buildings can reduce emissions and create affordable homes for communities. This is part of The Climate Group’s Home2025 project.
The Société d’habitation du Québec (Quebec Housing Corporation) – a government initiative which connects citizens to adequate housing and helps 225,000 households each year – has launched a demonstration project of 40 social and community housing units in Cité Verte, an eco-neighborhood in Quebec City.
Half of the building containing the housing units was built with cross-laminated timber (CLT), while the other half was designed using light wood framing – and all of it reduces energy consumption.
The building was designed under a technical cooperation agreement between the SHQ and the Istituto Trentino Edilizia Abitativa, which is building wooden social and community housing in both Italy and Quebec. In Trento, Italy, two five-storey timber buildings have already been built, each with 14 social housing units.
By comparing building construction methods in Italy and Quebec, the project will help improve respective costs and energy and environmental performance to ensure the sustainability and comfort of social housing.
The two regions also have complementary expertise: while Quebec has a tradition of affordable, low carbon light wood framing construction, Italy has developed knowledge in the use of CLT.
QUEBEC CITY
In Quebec, the demonstration building is located in a multi-residential complex in Quebec City’s Cité Verte neighborhood.
Eventually the complex will include 800 housing units and commercial spaces, including cutting-edge facilities such as rainwater management systems, an underground pneumatic waste collection system and a centralized wood pellet heating system to burn sawmill waste.
Already, the four-storey demonstration building includes:
- A thermal insulation building envelope that will cut heating needs by half.
- A solar wall air preheating system.
- A heat-recovery ventilation system (85% efficient).
- Hot water space heating supplied from a biomass plant.
After analyzing various energy simulations and envelope compositions, the final option targets annual consumption of 25 kWh/m2. By comparison, a housing unit built to current standards would use 60 kWh/m2 a year.
Triple-pane windows, reduced thermal bridges, improved weather stripping, added insulation and an efficient mechanical system all contribute to big energy savings – but only accounted for an additional investment of 3% during construction.
And this reduction in heating load and thus environmental impact and costs will also provide an attractive return on investment.
But how will these targets be measured? Not only will sensors track various parameters within the housing units and envelopes to monitor actual energy performance, after one year, data on heating use, ventilation systems and occupant behavior will validate whether the building is performing as predicted in the design phase.
The entire life cycle of the building was also analyzed to identify the environmental impact of all materials used. For example, the use of two different wood structures allows specific comparison of the distinctive acoustic, structural and thermal benefits.
Our work will go much further than the demonstration project. All of the analysis can help identify good design practices for limiting greenhouse gas emissions in the wider housing sector.
By using materials with low intrinsic energy input such as wood, and reducing energy use during occupancy, the affordable housing showcased in Cité Verte could eventually provide low carbon housing for all.