Novel energy retrofit
Noreen Fagan | April 20, 2015From the outside, the Victorian house at 31 Sussex Ave. in Toronto echoes the romanticism of a by-gone era but, once inside, the building transforms into an example of 21st century technologies. The 1879 red brick home is the stately research subject of Kim Pressnail, a professor of civil engineering at the University of Toronto and Russell Richman, a professor of building science at Ryerson University. The University of Toronto-owned house is part of a low-energy retrofit project designed by Pressnail and his former student, Richman. The project explores new and innovative approaches to low-energy housing. In 2013, the Sussex house was retrofitted to incorporate two-nested thermal zones. The box-within-a-box consists of a core and perimeter zone, each with separate temperature controls. The core contains the most commonly-used spaces such as the kitchen, dining room, bathroom and master bedroom while the perimeter contains non-essential spaces such as the ballroom and spare bedrooms. The house uses radiant floor heating, and has triple-glazed windows and foam insulation. But the key to saving energy lies in the ability to keep the two separately insulated thermal zones at different temperatures, which is what Pressnail and his team did for one year, beginning in December 2013. “We started out by heating the whole building, then gradually turned the heat down in the perimeter,” says Pressnail. In January, the permimeter's thermostat was set at 21 C. This allowed the researchers to see how the house would perform if all areas were heated. In February and March, the perimeter air temperature was gradually reduced to 5oC. This provided the researchers with the opportunity to evaluate the response of the ornate plaster ceiling in the ballroom. Generally, the perimeter areas can be turned down to 5oC or the average outdoor monthly temperature whichever is greater in order to achieve maximum energy savings during the winter season. But in April, as outdoor temperatures began to climb, the team allowed the perimeter temperature to increase to 10oC. “The goal was to save energy and increase the durability of the building – not degrade it,” says Pressnail. Tenants to move in The overall target was to save 75 per cent more energy compared to a home built to the 2012 Ontario Building Code (OBC) standards. In fact, the savings were 65 per cent, but if the perimeter had been operated in the maximum energy savings mode for the entire winter, they would have been closer to their goal, says Pressnail Although the initial research period has ended, the team will continue to record energy usage after new tenant – a visiting professor – moves in April 1. “We are going to monitor how the occupant, who has been given the tools to save energy, will run the house. We are going to sit back and see what happens,” says Pressnail. While Pressnail keeps tabs on the Sussex house, his future projects will include either building thermal zones into a new home or retrofitting a modern building. Although research done at Sussex house shows that thermal zoning is environmentally friendly, Pressnail doubts people will be rushing to retrofit their houses anytime soon. At a time when natural gas and oil prices are low, the cost of retrofitting outweighs the energy savings. “The game-changer will be when people start paying the true cost of what the energy is doing to the environment,” he says.