Summer heat waves trigger heightened demand for water along with electricity. Most large commercial buildings rely on chillers working in tandem with cooling towers to condition the air — accounting for 25 to 50 per cent of a building’s water consumption.
“The cooling tower’s job is to reject heat from the building, which it does by spraying water across a heat exchanger,” explains Eric Chisholm, technical lead with the engineering firm, WSP Canada Inc. “The more heat the building has, the more water the cooling tower has to use. On a hot, hot summer day, cooling towers are running full-out.”
Add irrigation and increased household demand (more showers, laundry and pool top-ups) and water use spikes upward. That also cycles back to electricity demand since municipal pumping stations and water treatment facilities are major consumers. Notably, the Toronto Water website admonishes that a tap left running for five minutes is the equivalent to a 60-watt bulb burning for 14 hours.
Unlike electricity, water rates do not vary on short-term intervals to reflect peak demand or the cost of supply, but they have been climbing steadily to help local governments fund needed upgrades to aging infrastructure. Toronto’s current rate of $3.1945 per cubic metre (m3) is 55 per cent higher than just five years ago as the city continues a multi-year program of annual rate increases.
Based on estimates that the average resident of Canada uses 0.3 m3 per day, that equates to about $350 per year or $1,400 for a family of four and still doesn’t necessarily create a significant financial incentive for conservation in the residential sector. Cost increases flow through much more noticeably to multi-residential and commercial water bills, though, prompting increased interest in efficiency and more precise user-pay formulas.
Many municipalities have now installed or are installing smart water meters, which have the ability to remotely collect consumption data (time-of-use as well as volume). Within commercial buildings, businesses in food courts have long been sub-metered for water to account for their higher consumption per-square-foot than other types of tenancies, but a broader range of owners and developers have begun to consider those economics.
“We’re doing a lot of water sub-metering in new condos now, which is a change,” reports Vince Brescia, president of Wyse Meter Solutions, a firm more often identified with sub-metering for electricity. “A couple of years ago, very few developers were sub-metering for water. They just didn’t think of it or see it as a priority.”
That’s likely due to the added complexity of water sub-metering in high-rise buildings, in which water enters a unit via several different risers — serving stacks of kitchens, bathrooms, ensuite bathrooms, etc — each requiring a meter. However, there is new impetus to pull water costs out of the general condo fees, allocated on a per-square-foot basis, and offer prospective buyers more flexibility to control their costs directly.
“Installing water sub-meters is not a problem in new construction,” Brescia says. “However, for a lot of the existing high-rise building stock, it’s not feasible due to a riser system design.”
With limited potential to pass costs through, landlords and condominium corporations may have more success adopting water-efficient technologies and promoting water-conserving behaviour. This is also in sync with the green building movement and corporate responsibility and sustainability mandates.
On that front, the Real Property Association of Canada (REALpac) sponsored a pilot water use benchmarking exercise in 2012 — drawing on data from 83 office buildings, representing 36 million square feet of gross floor area — to underpin the development of a water benchmarking methodology. A new water benchmarking program and database will be rolled out later this year as a companion to REALpac’s now well-established energy benchmarking program. Together, the programs are intended to provide real estate operators with a means to compare their buildings’ performance against others, and provide context for setting energy and water efficiency targets.
“For the industry at large, collective participation allows for greater transparency, which moves the needle of performance and pride even further,” says Julia St. Michael, REALpac’s director of research and sustainability.
Stewardship and tenant engagement
BOMA BESt environmental performance certification and the Certified Rental Building (CRB) program’s new Living Green component also focus on water, while Landscape Ontario has just launched the Water Smart Irrigation Professional (WSIP) certification in partnership with the Region of Peel and the Regional Municipality of York.
“It’s about looking at water from a stewardship perspective,” says Tony DiGiovanni, executive director of Landscape Ontario. “It’s based on measuring water use and reducing what you use in balance with what you need.”
After cooling towers, irrigation can be one of the next largest uses of water. DiGiovanni laments that it’s also often wasted unnecessarily. Sprinklers on timers set to activate regardless of recent or in-progress rainfall are on-the-ground culprits. In the bigger picture, he critiques development patterns and construction/engineering practices that escalate storm runoff rather than capturing a critical resource.
“The landscape doesn’t even like treated water. The landscape likes the water that falls from the sky,” he asserts.
In commercial buildings, tenants’ actions can have a direct and significant impact on electricity consumption, whereas with water, landlords really just need philosophical buy-in for water-saving features such as recycling rainwater or grey water for use in toilets.
“Water has challenges in terms of tenant engagement because tenants generally have limited control on water conservation levels at a building. It’s mostly about awareness building,” acknowledges Kyle Pinto, sustainability manager with the energy and environmental consulting firm, [email protected]
He recounts how adding dye to the harvested water supply was a simple solution in one Toronto office building where some tenants balked at discoloured rainwater in the toilets. Proactive openness is also important.
“We’ve been working with an anchor tenant that highlights building sustainability features as a draw to new employees,” Pinto notes. “We were able to take the prospective hires to the green roof and to the mechanical rooms to explain what makes the building unique. In this case, that includes water savings through the building’s connection to the Enwave deep lake water cooling system, which, in conjunction with other design features, has eliminated the need for cooling towers.”
Tapping into deep lake water cooling is something of a niche option for buildings located within the scoped area the system serves in downtown Toronto, but water saving results are dramatic. For example, in 2014, the average water use intensity for the office towers obtaining Level 2 to 4 BOMA BESt certification was 0.68 cubic metres per square metre (m3/m2/yr), while one building connected to the deep lake water cooling system recorded a water use intensity of 0.27 m3/m2/yr.
Alternatively, Chisholm points to much simpler interventions. “The easiest thing to do is put low-flow aerators on sink faucets. Aerators only cost a few dollars and you don’t need a plumber to replace them; you just need a good wrench,” he advises.
Chisholm sees plenty of other untapped saving opportunities that could be achieved at relatively low cost. Yet, perhaps ironically from a sustainability perspective, the durability of plumbing fixtures can be an obstacle.
“Those old inefficient incandescent bulbs didn’t last long so every month or two you’d have the opportunity to replace a few with something better, but a toilet can last for 20 years or more,” he says. “There are still a lot of old toilets out there waiting to be replaced, and all the while they’re flushing money down the drain.”
Barbara Carss is editor-in-chief of Canadian Property Management.