Performance gap reality check: Why aren’t buildings operating the way they were designed to?

Translating green building policies for new construction into practical results is challenging. Governments often focus their policies on what buildings are supposed to do, without measuring and responding to their real-world performance.

In principle, getting new buildings to use less energy and emit less carbon shouldn’t be complicated. We know what to do. The technology is proven and ready for prime time. The incrementally higher cost of better design and construction pays for itself in lower operating costs, healthier indoor environments, happier and more productive occupants, and better ability to withstand the next storm, heatwave, or power outage. And it’s far cheaper to build net-zero-ready than to retrofit buildings down the road.

Unfortunately, the strong societal case for low-carbon new construction doesn’t translate into market incentives for builders. Builders don’t pay the operating costs, or benefit financially from health, productivity or resilience benefits of green buildings. Carbon pricing, for example, is completely ineffective in new construction. Most buildings are designed to the minimum applicable regulatory standard. Which is why building codes and municipal green development standards are critical. If only it were that simple.

In theory, energy codes and standards have improved dramatically over the past three decades. A large building built to current Ontario Building Code (OBC) standards is supposed to use about 28% less energy than one designed to the 1993 OBC. A building built to current Toronto Green Standard requirements (V4) should use a whopping 47% less energy than one designed to the 1993 OBC. Yet when we look at the real performance of buildings through benchmarking programs, a very different story emerges. Buildings built in the 1990s on average have about the same energy use intensity (EUI) as buildings built in the 2000s or 2010s. What’s going on?

Over the last decade or more, TAF has identified three reasons why stronger codes and standards haven’t always translated into better real-world performance:

• Conventional building energy codes are overly complex and subject to varied interpretations, resulting in buildings that fail to meet the community’s energy and emissions goals;
• Key aspects of energy performance are assumed in energy models but never verified during construction, leading to widespread construction quality issues impacting performance;
• Even when a new building is on target in its design and construction, problems with operations and maintenance often undermine performance.

Performance is open to interpretation

The first major bottleneck is the way performance standards for large buildings are set. They’re typically based on a complicated set of guidelines with multiple compliance options. Every building proposes its own unique energy target based on the building designer’s interpretation of code requirements. Ask a handful of engineers to calculate the energy code requirement for the same exact building, and you will get different answers often varying by 30% based on professional judgement.

This system also creates an inherent conflict of interest. The professionals interpreting the code are working for the developer, whose primary interest is to complete the building as quickly and cheaply as possible. With little oversight and other firms willing to offer different interpretations, design professionals are under competitive pressure to provide clients with maximum flexibility to continue with business-as-usual. While most would prefer to design better buildings, firms that are too rigorous in interpreting energy codes may find their client list dwindling.

Some GTHA cities like Toronto, Brampton, and soon Mississauga, have sought to solve this problem by introducing absolute energy and emissions targets for each building type. Toronto led the way with version 3 of the Toronto Green Standard (TGS) in 2018, and most other municipal green standards have followed suit. For example, every new condo in Toronto has to meet a carbon target of 15 kg CO2e/m2/year (no interpretation necessary), with targets getting stricter over time. Absolute targets make it harder to game the system and put the design focus where it should be – on meeting or exceeding energy targets as cost-effectively as possible. But the benefit is muted by national and provincial building codes that still rely on the antiquated code reference approach.

How to get construction quality right

The second challenge is that compliance with codes and standards is judged based on energy models (computer simulations), which rely on certain assumptions about construction details. For example, one of the most important variables is air tightness, as leaky buildings waste a tonne of energy on heating and cooling. Air tightness depends both on design and construction quality, and the assumed values are almost never verified during construction. Evidence suggests most buildings are leakier than they were designed to be.

The only sure way to correct this is to require air tightness testing in codes and standards. This was proposed for the last edition of the national energy code but cancelled due to industry and provincial concerns about the availability of industry capacity to do the required volume of testing. This is a classic chicken-and-egg type problem, as no one wants to invest in the capacity if its not mandated, but no one wants to mandate it until there is industry capacity.

Theory meets practice  

The last big obstacle is human behaviour. Buildings are occupied and managed by people, and people make mistakes and behave in ways that models don’t predict. Almost invariably, real life falls far short of even the best design intentions.

For example, an energy model will assume that the building automation controls are optimized to get the best possible performance from heating and cooling systems. But sometimes no one bothers to optimize the controls to begin with, or building operators change the settings in ways that erode performance. There are a few factors that make this a tough problem to solve—from unrealistic energy modelling assumptions to building management teams that aren’t always trained to properly operate and maintain the equipment.

There is no easy solution to this problem. Mandated commissioning of new buildings would be a good start. Better smarter controls designed to identify and correct for human errors can help. Ultimately, getting buildings to perform as designed will likely require building performance standards for existing buildings, such as those in place in Vancouver and under development in Toronto.

Last chance to get it right

The mix of gaps and near misses won’t be solved overnight, but it must be dealt with soon.

Large buildings operate with long replacement cycles. So a new structure that goes up today will have no major equipment renewal scheduled by 2050, the year when every city’s emissions must hit net-zero, barring extraordinary effort by the owner or extraordinary incentives from governments.

That means the performance those buildings deliver tomorrow will essentially be the performance they deliver for the next 25 years.

Until now, few have paid close attention to the way new buildings perform after they’ve been built, and municipal staff have had limited resources for code enforcement. That makes the performance gap a great opportunity for learning, action, and continuous improvement. There are many practitioners across the building trades and professions who want to get this right. What’s needed now is the leadership, consistency, and day in, day out effort to turn strong standards and good intentions into buildings that work the way they should.