Making the Invisible Visible: Designing for energy efficiency with insulation

October 28, 2015

Photo courtesy Paul Filitchkin

By Tara McClinchey
Buildings are energy hogs. Nearly half the total energy consumption[2] of commercial and industrial buildings in Canada is used for heating and cooling spaces, which contributes to 42.9 per cent of the sectors’ greenhouse gas (GHG) emissions. Thus, important measures are taken to reduce the energy consumption of buildings, with a special focus on heating and cooling loads. This has presented a challenge for design professionals over the last few years. How can a building be designed to maintain its exterior beauty while nevertheless still significantly reducing its energy consumption?

The high-rise buildings dominating most downtown cores across Canada may be pleasing to the eye, but what really counts is hidden behind the walls. Not only do wall assemblies including fibreglass, rock, and slag wool (i.e. mineral fibre) insulation provide peace of mind with effective moisture and fire protection, but they also have much to offer by reducing a building’s energy consumption.

For example, they can offer savings on utility bills, which can then be invested in business growth opportunities or improved competitiveness, such as reduced prices for consumers or higher profits for shareholders. (These savings vary, as explored in the seller’s fact sheet on R-values. Higher R-values mean greater insulating power.) Highly insulated and well-ventilated buildings can also provide its occupants improved indoor air quality (IAQ), which could have an impact on health, well-being[3], and overall productivity.

The market for energy-efficient buildings is expected to grow. These code requirements are becoming more stringent, and energy efficiency labels on buildings are growing more recognizable. Canada has adopted a benchmarking system—making it easier for building owners to track and assess their energy consumption, and to compare their performance with other buildings of a similar type. It is important buildings are designed not only to look esthetically beautiful, but also be energy efficient. This means taking mineral fibre insulation into consideration when designing the building envelope.

Examining the energy efficiency code requirements
The commercial building sector is changing as more jurisdictions across Canada move to adopt the 2011 National Energy Codes for Buildings (NECB) or their own energy efficiency codes (e.g. Supplementary Bulletin 10 [SB-10] of the Ontario Building Code [OBC]). While the 1997 Model National Energy Code for Buildings (MNECB) was the first to introduce energy efficiency standards for commercial, institutional, industrial, and large residential buildings, it is the 2011 NECB that has been effective at setting a precedent for more stringent minimum energy requirements[4] in much of the country. This has put Canada in the running with other countries[5] leading the way in energy-efficient construction.

Taking a holistic approach to design, NECB allows designers to take either prescriptive, trade-off, or performance paths. In other words, there is some flexibility in design, as long as the building does not consume more energy than it would have otherwise. A building designed with more windows, then, would be required to compensate for its higher ability to transmit heat (known as the heat transfer coefficient, or U-value) by increasing the level of insulation, for instance, in the remaining parts of the building envelope.

The national energy codes are typically revised every five years, and the next version of the NECB is expected later in 2015, but has minimal changes to energy efficiency. The plan for the version after that (to be released in 2020) is to improve energy efficiency by 20 per cent. Currently, there are numerous proposals being discussed that would affect the building envelope and required insulation levels, including lowering the maximum U-values for each climate zone, limiting trade-downs in the performance and prescriptive paths, and reducing the number of skylights allowed.

As the provinces and territories adopt the revised NECB, once high-performing buildings might lag behind new buildings. Therefore, designing buildings with insulation levels beyond what is required by code can offer building owners added value in the long run. Voluntary programs, such as building certification and benchmarking, can also provide designers the motivation to do just this, which, in turn, increases the supply of energy-efficient buildings on the market.

The market for energy-efficient buildings and certifications
Building certification has done a lot for raising awareness and opening up the demand for ‘green’ buildings that are said to be more energy-efficient than those built to code. Most people could probably identify the Energy Star label or recognize the Leadership in Energy and Environmental Design (LEED) plaque on a building. Some will even pay a premium to occupy spaces in green-certified buildings with the understanding they will save money on their energy bills and that they can advertise they are doing their part to help the environment. Certain businesses will also pay a premium for the added benefit and competitive advantage of attracting people who want to work in healthier and environmentally responsible offices.

However, spotting an energy efficiency label on a high-rise building made with large window areas raises some questions. Such as, how much energy will the building conserve? Is it actually more efficient than the uncertified ones?

For such a building to merit a strong energy label, the interior must compensate for the poor efficiency of the building envelope. However, what happens when the interior mechanicals (i.e. HVAC and hot-water systems) are not well-maintained, or a subsequent tenant replaces parts of the building interior? It is suggested the most durable, sustainable contribution to a building’s energy efficiency is its well-insulated envelope rather than its interior features.

These downtown Toronto buildings have outer shells composed mostly of glass – making insulation and energy efficiency more challenging. Photo ©

There are numerous certification programs recognized in this country, including Canada Green Building Council’s (CaGBC’s) LEED and Building Owners and Managers Association (BOMA) Canada’s Building Environmental Standards (BOMA BESt). BOMA BESt certifies existing commercial buildings after assessing the environmental performance and management, not only accounting for its energy-efficient design, but also its performance over time. Applicants are required to submit utility bills, so certification is granted to buildings that can demonstrate energy savings. Additionally, since recertification occurs every three years, the label maintains the building’s continued status as energy-efficient.

On the other hand, although the LEED standard is widely recognized and frequently adopted by governments, it has been criticized for certifying buildings that do not demonstrate higher levels of energy efficiency when compared to those built to code. This could be in part due to the certification process and to the application’s rating system. Firstly, applicants do not need to recertify after a specified amount of time. Secondly, the focus of the rating system’s energy section includes sustainable materials and resourcefulness, indoor environmental quality, and overall energy performance.

However, one of the drawbacks cited of the LEED standard is the lack of focus on the building envelope. Despite containing highly efficient mechanics or sustainable materials, a building constructed without regard to its building envelope could result in the consumption—and waste—of a large amount of energy.

The developers of the LEED program recognized certified buildings require maintenance to continue to function efficiently. For this reason, the rating system also includes a benchmarking tool that allows the buildings’ owners and managers to monitor their energy consumption, and compare its current levels to what was achieved at the time of certification.

On the path to standard benchmarking
Thanks to some benchmarking tools, owners and residents can see how their buildings’ energy consumption compares to others. These tools could result in a larger market for energy-efficient buildings.

Natural Resources Canada (NRCan) is currently in the process of adopting the U.S. Environmental Protection Agency (EPA)’s ENERGY STAR[7] Portfolio Manager. This benchmarking tool has been successful in the United States as it is the leading tool, with 40 per cent of commercial building space using it—including more than half the Fortune 100 companies, and half of the largest healthcare organizations, education facilities, and municipalities. The success story is expected to continue in Canada, as thousands of commercial buildings have already been registered and green building certification programs, such as BOMA BESt and LEED, align their requirements to it[8].

To merit an energy efficiency label, buildings with many window areas must contain highly energy-efficient mechanicals to compensate for inefficient envelopes. Photo courtesy S. Charles

In Canada, it is being adopted as the platform for the nationwide benchmarking program for existing buildings. Since its inception in July 2013, more and more building types are able to register. To date, K-12 schools, commercial office buildings, hospitals, supermarkets or food stores, and medical offices can register, with more to be added.

Municipalities have used the tool to motivate building owners and managers to benchmark and retrofit their buildings. For example, the Great Toronto Civic Action Alliance’s Race to Reduce [10]aimed to lower the energy consumption of registered office buildings by 10 per cent within four years. The City of Richmond, B.C., has the EnergySave program[11] where they set a goal to lower GHG emissions by 33 per cent by 2020.

As an alternative compliance path, NECB is currently evaluating CSA Group’s C873 Series-14, Building Energy Estimation Methodology (BEEM)[12]. Adapted to the Canadian market, it provides simplified building energy calculations with results similar to those modelled in CanQuest—Canada’s building energy simulation software that can be used to demonstrate performance path compliance with the NECB—and has a proven track record of more than eight years in Germany. If the proposal for its adoption into the NECB is accepted, it will allow existing buildings to benchmark their energy performance to new builds. This could be the motivation owners and managers of existing buildings need to invest more in energy efficiency.

What makes benchmarking different to other ‘green’ initiatives is it shows people how their buildings measure up, and where their strengths and weaknesses are when it comes to energy efficiency. Perhaps their mechanicals are poorly functioning, their technology is outdated, or the building is insufficiently insulated. Benchmarking would show a building with highly efficient mechanicals, but poor insulation is still a leaky energy hog.

Though energy efficiency codes push for tighter building envelopes and energy labelling helps grow the market for ‘greener’ buildings, it is energy benchmarking that is changing the game. It shows building designers, owners, and managers which measures will have the largest impact on reducing energy consumption, and they can see whether their buildings are energy efficient or not. Benchmarking makes the invisible visible, and it shows preference for energy-efficient designs, rather than purely esthetic ones.

author[13]Tara McClinchey serves as the research/communications co-ordinator for NAIMA Canada, an association for manufacturers of fibreglass, rock, and slag wool insulation conducting business in Canada. Through her research and marketing efforts, she has promoted energy efficiency and environmental preservation through the use of insulation. She can be contacted at[14].

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