University of British Columbia

Building energy code boosts performance

British Columbia will be the first province to officially adopt NECB 2011
Tuesday, November 12, 2013
By Martina Soderlund

A building energy code establishes minimum performance requirements for the design and construction of buildings and their systems. In Canada, approximately 30 per cent of total energy consumption and 25 per cent of greenhouse gas (GHG) emissions are generated by the building sector.

Achieving reductions in building energy use is crucial to reduce GHG emissions and pollution that is caused by the combustion of fossil fuels and the generation of electricity. The environmental advantage of energy efficiency in buildings is a benefit at both the local and global scales, and will continue over decades of time.

The adoption of building energy codes in Canada has fallen behind compared to adoption rates of similar codes in the United States and Europe. Canada’s Model National Energy Code for Buildings (MNECB), first published in 1997, has been referenced occasionally in some jurisdictions, but has low adoption rates in provinces or territories. In an attempt to improve this, the National Research Council (NRC) published an updated version, the National Energy Code of Canada for Buildings (NECB) 2011, which offers significant improvements over the original 1997 version.

The new NECB 2011 must be adopted by provincial and territorial authorities in order to become law. In December 2013, B.C. will be the first province in Canada to officially adopt the code for all new large residential, industrial, commercial and institutional buildings. The B.C. building energy code also provides the option of using ASHRAE 90.1-2010 as alternative compliance code to the NECB 2011. Other provinces are likely to follow, but deliberations are still ongoing.

The new NECB 2011 claims to be on average 26 per cent more efficient than the preceding MNECB. Further, there are relative performance ratios between NECB 2011 and ASHRAE 90.1-2010. If there is an option to use either code, which one will lead to the best performance in the most cost-effective way?

A study completed for NRC found that NECB 2011 is generally more efficient than ASHRAE 90.1-2010, especially in colder regions, due to more stringent envelope requirements and higher efficiency heating equipment. But there are variations to note.

Envelope insulation levels for roofs, walls, windows and floors are significantly more stringent in the new NECB 2011 compared to the current version of MNECB, as well as compared to ASHRAE 90.1-2010. One significant change to note in NECB 2011 is the limitation on maximum prescriptive glazing percentage to gross wall area, which now varies with climatic region.

Vancouver‘s allowable percentage is 40 per cent, while Calgary‘s is limited to 33 per cent and Yellowknife to 20 per cent. ASHRAE keeps this prescriptive area to 40 per cent, and both codes allow trade-off options if exceeded.

Installed lighting power densities are significantly more stringent in the new NECB 2011 code compared to MNECB, and are similar to the ASHRAE 90.1-2010 requirements. More emphasis is put on electrical lighting control and integration with daylighting. There are also new requirements to limit exterior lighting based on whether the project site is urban or remote.

NECB 2011 is silent on the issue of plug-load controls, however, plug loads can account for up to 25 per cent of buildings energy consumption and is one of the most difficult end-uses to tackle for improved building energy performance in today’s device-dense world. ASHRAE 90.1-2010 requires automatic plug-load control in some spaces like offices and computer classrooms.

HVAC efficiency ratings for heating and cooling equipment have been increased slightly, and more details on ventilation heat recovery are in place, including a new NECB 2011 requirement on heat recovery for swimming pools and ice rinks. ASHRAE 90.1-2010 better addresses controls on kitchen and laboratory exhaust systems.

Renewable energies and alternative energy sources are not addressed directly in either NECB 2011 or ASHRAE 90.1-2010. The code refrains from imposing barriers on the use of renewable sources, as a variety of technologies exist and the benefits vary greatly across regional contexts. However, credit is available for renewables in the energy performance path.

It is important to assess how the new code will integrate with the energy performance targets required by the LEED (Leadership in Energy and Evironmental Design) rating system, the Living Building Challenge (LBC) and Architecture 2030. LEED Canada 2009 currently compares a proposed building design performance to the old MNECB or ASHRAE 90.1-2007, which means different code comparisons to possible adoption of NECB 2011 or ASHRAE 90.1-2010.

Streamlining the process for compliance would benefit the industry, promote rating system uptake and performance improvement, as four different options for baseline code comparison adds complexity and inefficiency. Architecture 2030 is compared to a benchmark energy intensity target for fossil fuel reductions, and the LBC is based on actual performance to verify net-zero energy. This means moving well beyond minimum energy code compliance in design.

Truly high performing buildings in today’s marketplace are much a result of voluntary efficiency measures and targets on a project-by-project basis, rather than a result of mandates from provincial or territorial energy efficiency requirements in legislation. Adopting a minimum standard for energy performance is a step in the right direction for jurisdictions where none yet exist .

But to take a big bite out of the 30 per cent of energy consumed by the building sector in Canada, targets like passive haus, net-zero energy, net-zero carbon or a regenerative approach to building design should be part of the dialogue. This means clients and design professionals need to acknowledge that moving well beyond the new energy code is a requirement for achieving a true market shift in building energy performance.

Martina Soderlund, M.Sc., is a senior sustainable building and energy advisor at Perkins+Will.

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