Green behind the scene

Green Behind the Scene – This homes showcases extreme energy efficiency

Written by: Judy Liebner
Photos by: Richard Bain

Many homebuyers focus on features such as granite counters, see-through fireplaces and hardwood flooring when they tour model homes.

In Doug Tarry’s Thornwood model home however, the elements that will most impress visitors are those that are concealed.

Tarry, director of marketing for Doug Tarry Homes in St. Thomas, Ontario, designed the house to showcase its energy efficiency. Everything from the insulation to the mechanical system was chosen to protect a potential buyer from rising energy costs.

“We wanted homes to have better performance,” says Tarry, who is also president of the Ontario Home Builders’ Association (OHBA). “It’s the coming trend that’s happening in our industry in the next 12 years. We very much wanted to be on the leading edge.”

One key feature of the home is the insulation. The walls in the lower level are insulated with R20 Roxul insulation, which adds greater warmth and resists moisture, mould and fire. It also helps to deaden sound.

The main floor of the 1,460-square-foot bungalow-style home was constructed using R27 Roxul wall insulation.

“One of the things we’re finding is how quiet this house is,” Tarry explains. “It’s very comfortable and it has consistent heat as well. We’re not losing very much in the way of heat.”

To reduce the owner’s electricity expenses, the home has been equipped with Energy Star-compliant LED lighting. The ECM motor for the fan in the en suite bathroom is barely audible and is highly energy efficient.

“It’s providing performance while saving money,” Tarry says.

Downstairs, Tarry “right-sized” the Thornwood’s mechanical system to reduce its use of electricity and maintain an even temperature throughout the lower level and the main floor. A consistent temperature is difficult to achieve as homes become tighter and more energy efficient. As a result, the main floor stays warm, but the lower level can feel uncomfortably cool.

To overcome that problem, Tarry opted for a Lifebreath Clean Air Furnace that combines a hydronic air handler and an energy recovery ventilator (ERV). The system uses water from the water heater to warm the air coming from the furnace, then returns the water to the water heater, providing a steady stream of temperate air that is more comfortable than conventionally heated air.

Overall, the system uses one-fourth of the electricity used by a regular furnace and heat recovery ventilator. It also helps remove stale air from the home and replaces it with an equal amount of fresh air while recovering 70 per cent of the heat energy. Tarry says the ERV maintains optimal humidity within the home.

An ECM high-efficiency furnace motor constantly mixes warm and cool air. “It’s being done so quietly that you don’t know it’s actually happening,” he says.

The home, priced at $299,913, also includes a solar-ready rough-in, which will allow buyers to heat their hot water with solar thermal power. When the set-up is completed, it will reduce energy costs by about 60 per cent for domestic hot water.

In addition, the home includes a drain water heat recovery system that recovers heat from warm drain water, saving 30 per cent of water heating costs; a higher-efficiency air conditioner sized to individual homes; a condensing water heater with 90 per cent thermal efficiency, and a plug-in electric vehicle rough-in, which allows for a future charging station for electric vehicles.

The home incorporates Low-E North Star low solar gain windows that are manufactured in St. Thomas. Low solar gain windows lessen heat gain in summer, which reduces cooling costs. In the Thornwood, the windows were installed on the east-facing exposure at the rear of the home. The orientation of the home and the use of overhangs will also help to limit solar heat gain in summer and warm the interior in winter.

The Thornwood is a Discovery home, one of 10 being built by members of the London Home Builders’ Association as part of the Technology Adoption Pilot (TAP). TAP is the next step in Natural Resources Canada’s Local Energy Efficiency Partnership (LEEP) program, which was launched in London, Ontario in 2006 to encourage home builders and consumers to adopt the latest in energy-saving technologies and products.

Through LEEP, builders assessed and selected the technologies that could work best for them in their construction processes. The goal is to find the ones that can be incorporated into mainstream construction as builders move towards higher-performance housing. TAP and LEEP are being coordinated by EnerQuality Corporation.

Of the 10 technologies chosen for demonstration in the London market, the Thornwood includes seven. Tarry took his own housing market into consideration when choosing the ones he would use.

“For my market, the Roxul insulation is a good way for me to go because of cost and what the market will handle. I have to find ways of doing things cost effectively because of the market I’m in,” Tarry says.

“I don’t quote dollars and cents. I talk to them (homebuyers) about comfort. It’s really about the comfort, use and enjoyment of your home.”


1. The great room features a 10-foot-high ceiling, ash hardwood flooring and a wide archway that opens to the kitchen/dining area.

2. The dining area is handy to the kitchen and also to patio doors that open to the backyard.

3. The kitchen combines maple cabinetry with laminate counters that resemble travertine marble. The workspace was designed by interior design consultant Gabi Brown and Jen Gilmore of GCW Custom Kitchens and Cabinetry.

4. The foyer is bright and wide, creating a sense of spaciousness within a compact area.

5. The ensuite bathroom can accommodate a roll-in shower for owners with mobility problems.

6. The spacious master bedroom is decorated in an old world vintage style that relies on painted woods with a distressed patina