NET ZERO ENERGY MURBS

The future of Multi-Unit Residential Housing in Canada

Over the past 6 years, the Canadian Home Builders' Association (CHBA) along with an enthusiastic and leading edge group of builder members have been "pushing the envelope" on energy efficiency of residential housing. In collaboration with Natural Resources Canada, industry partners, suppliers and Building Science consultants, CHBA facilitated the voluntary industry-led Net Zero Home Labeling Program from the concept and development stage into implementation and construction of Net Zero Energy homes. After the official launch in 2016 for Part 9 houses, this voluntary program has seen success in low rise residential homes across the country and is expanding to include Multi-Unit Residential Buildings (MURBs) as well as Renovations of existing homes.

Net Zero Energy (NZE) home generates as much energy as it uses in a calendar year through the use of onsite renewables. A Net Zero Energy Ready (NZE/r) home is designed and constructed the same way as an NZE home, however the onsite renewables have not been added to the home (yet). "Net Zero Homes produce as much clean energy as they consume. They are up to 80% more energy efficient than typical new homes and use renewable energy systems to produce the remaining energy they need." www.NetZeroHome.com. Should homeowners of NZE/r homes choose, they may add the required renewables at a later date and the home could then qualify to be labelled Net Zero Energy.

Climate change has been in the news for years now. Globally, building codes are tackling energy consumption and carbon related issues by incorporating increasingly rigorous energy efficiency measures, delivered in incremental steps. This move is in response to the Pan-Canadian framework, a Canadian plan adopted by most of the provinces and territories in 2015, with set targets for reducing emissions, increasing resiliency in homes to adapt to climate change, and growing the economy by 2030. These energy conservation goals are not unique to Canada; as other countries are on the same trajectory with their building codes.

Taking incremental steps in order to achieve greater success in the long run is the correct approach. It will also be important that each step not be regulated until it can be shown to be cost effective. It can be tempting for some to want to make rapid changes, pushing to shorten the time frame for hitting Net Zero Energy Ready. However, sudden jumps in housing prices due to rapid code changes can be devastating for Canadians trying to afford a home. Currently we have a housing crisis on two fronts; affordability and availability of housing supply. Many factors are culminating to result in this crisis, including policies impacting mortgage rules, materials shortages and price increases, and the shortage of skilled labour. Sudden mandated jumps, in an effort to speedup the timeline would exacerbate an already existing crisis pushing even more Canadians out of the possibility of home ownership.

Constructing housing that's even more energy efficient than the current building code requires additional levels of training and understanding by the builder, trades and industry partners around the concepts of building science. Unintended negative consequence can occur if energy efficient measures are added to homes without understanding how the "house-as-a-system" operates. Proper training of builders and trades takes time and is necessary to avoid widespread issues, resulting in unhealthy homes. The CHBA Net Zero Home Labeling Program is voluntary for these reasons. It allows for leading edge builders to work through the process, learn the early lessons, and lay the ground work, so that these lessons can be shared with the industry at large and all will have a much higher level of success. This is a win for the builders, the trades and the industry, a win for the Canadian economy, but most importantly a win for Canadian homeowners.

Since we know these changes are coming over the next 10+ years, we need to begin the process of learning, training, and adapting our approaches to meet these new targets at a cost Canadians can afford.

The Net Zero MURB Pilot has officially launched with the objective: "To validate the use of panelized/modular construction and integrated mechanical system technologies, design and construction practices on Net Zero or Net Zero Ready MURBs to optimize energy efficient performance, reduce costs, increase construction productivity and reduce construction schedules." Essentially the goal of the pilot is to build better, faster, and for less cost. Housing affordability is crucial for Canadian families' financial futures and a healthy economy, therefore when developing a voluntary program like this, extra attention is paid to building a product that has beneficial conservation measures that have proven beneficial through a cost-benefit analysis.

This pilot is in partnership with Natural Resources Canada. Other notable stakeholders include six builders, four additional partners, fourteen product solution partners, five consulting firms and is in partnership with Natural Resources Canada.

Building Knowledge Canada is pleased to be the Lead Energy Consultant and facilitator of this pilot project.

By Province, the six builders participating in this pilot project are:

Over the course of the next few years, the pilot will run through four stages.

  1. Planning: During this stage the builders will work with their teams to design and optimize their plans to achieve the goals and outcome of the pilot program.
  2. Building: During this phase the builders will construct the homes and implementing the plans developed.
  3. Analyzing: After the homes are constructed, an analysis of the cost of construction savings as well productivity gains will be tallied and compared to standard code built homes.
  4. Sharing: Through education and training sessions, the learnings will be shared from coast to coast, to aid in capacity building and assisting builders in moving toward Net Zero Energy Ready.

Some Key Performance Indicators for the project are:

  • Energy and Emissions reduction - Optimizing building energy performance, and reducing energy usage, and carbon emissions of the home
  • Financial - Developing measures and methods for reducing the cost of construction. Developing methods for increasing construction productivity. Reducing construction timelines. Reduction in the energy usage and operating costs of the home
  • Material waste - Optimizing construction plans and materials to design out waste. Waste diversion for the remaining waste.
  • Occupant Comfort - temperature, humidity management, noise and odour reduction, daylighting

As the builder's team works in collaboration with industry partners through the design and planning process phases, some key learnings are beginning to emerge:

  • Windows, Air tightness and ventilation have the biggest impact on overall performance of the home.
  • Dual fuel hybrid systems (natural gas furnace with electric air source heat pump) are an economical choice for consumers in some areas of Canada.
  • Domestic hot water is the next big load we need to address.
  • Space cooling loads are now more of a concern than space heating loads. The Solar Heat Gain Coefficient (SHGC) of windows impacts occupant comfort, cooling loads and mechanical sizing dramatically. Strategically selecting windows with the proper SHGC is crucial.
  • Humidity control strategies must be addressed.
  • ERVs (not HRVs) may be the most appropriate option for NZE MURBs in many climate zones.
  • Proper load calculation (CSA-F280-12) are critical in rightsizing the furnaces for optimal performance and comfort.
  • Distribution of conditioned air and ventilation is critical for occupant health and comfort.
  • Selecting the right thermostats and controls is critical for system performance.
  • Cost of operating is a provincial and regional decision matrix as natural gas vs electric vs hybrid are different depending on province and region.

As these NZE/r MURB projects move forward, new learnings will be shared with the industry as we work to expand industry knowledge, training and capacity to meet the energy targets of the future. The team at Building Knowledge Canada is thrilled to be the lead energy consultant and facilitator of the voluntary CHBA Net Zero Energy MURB pilot project, and look forward to our continued work with the builders and industry partners as we move this important industry leading voluntary initiative forward.

This article was originally published by Stefanie Coleman on LinkedIn.