How a Milton, Ontario commercial building will produce more energy than it uses

Markham-based Del Ridge Homes has started construction on The GreenLife Business Centre in Milton, Ontario, which will be the first net-positive energy office building in Canada. It was designed by Radek Kozlowski Architect.

Over the past four or five years Markham-based Del Ridge Homes has been building a reputation for its green buildings. With a mandate of net-zero energy — meaning its buildings produce as much energy as they use — Del Ridge has set the bar high.

But its latest project goes a step further.

The developer/builder has started construction in downtown Milton on a 32,000-square-foot office building — the first net-positive energy office building in Canada, according to Dave De Sylva, who along with partner George Le Donne, runs Del Ridge.

Net-positive means more energy is produced than used. The GreenLife Business Centre on Bronte Rd. will produce about 168,000 kWh but only need about 100,000 kWh to operate annually, he says.

Designed by Radek Kozlowski Architect, it will be completed at the end of this year.

Many of the energy-saving principles employed in the new building also were used in other net-zero projects by Del Ridge, including a just-completed office building in Markham and several multi-residential projects in the Greater Toronto Area.

One of the developer/builder’s standard construction practices involves using “enhanced” insulated concrete forms (ICFs) that have insulation on both sides. It brings a wall’s insulation value to R-42, says De Sylva, an engineer by training.

Del Ridge goes a step further than many builders using ICFs by starting them not at the walls but rather at the footings. It helps maintain the ambient temperature of underground parking garages at 16-17 Celsius, which eliminates the need for heating, he points out.

Ramps to underground parking are enclosed, saving an estimated 80,000 kWh annually in energy costs.

Typically, Del Ridge installs up to 18 inches of expanded or extruded insulation in its roofs for an R value of 70 to 75, he says.

To complete the building envelope, Del Ridge specifies thermally broken triple glazed windows, he says, adding that motion sensor lighting and daylight harvesting lighting (mostly LED or compact fluorescent lighting) are specified for common areas.

To reduce the energy costs of hot water in its buildings, Del Ridge has a system of tempering the water either through geothermal equipment or decanting energy into a pre-tank on each floor from heat sources such as photo-voltaic inverters. The stored heat (24-26 Celsius) is passed to users by demand.

“It avoids thermal losses because you’re above the ambient temperature of the building,” De Sylva points out.

Geothermal and Energy Recovery Ventilation are integral to all of Del Ridge’s new buildings. “The investment in geothermal becomes extremely lucrative because we are operating at about a quarter of the actual energy demand after we have conserved everything.”

The net-positive office building in Milton will include a photo-voltaic array that produces about 120 kilowatts.

Surprisingly, De Sylva says Del Ridge’s residential and office buildings are priced at less than comparably-sized buildings without as many high efficiency features.

It costs $220-$240 per square foot for its office buildings compared to $280 a square foot for other developers’ buildings.

How does Del Ridge beat the price of standard construction?

“Go ask them,” De Sylva says, suggesting there are a number of ways that Del Ridge designs and constructs its buildings to keep costs down without sacrificing quality or energy efficiency.

“We’re practical people and very hands on,” adds De Sylva’s partner Le Donne.

“Practicality is what is missing in this industry,” Le Donne adds.

“Nobody questions their consultants (or their fees) but we have put together a group of consultants where everybody looks for ways (of keeping costs down).”

De Sylva says too many builders and developers put up buildings the same way they have done for many years. Indifference to change – how to build a better building – is commonplace.

Del Ridge doesn’t just put up a building and walk away boasting about high energy performance.

Measuring how a building performs (through energy metre consumption measurements) two or three years after completion is an important part of its agenda.

It is part of a whole package that too few developers and builders are taking seriously, the partners suggest.

“The building industry is slow to change I think because it lacks conscience,” adds Le Donne.

“We have kids and grandkids — that’s what you need to think about .”