Researchers test heat-recycling design in a downtown Toronto home

Tuesday, January 29, 2013 10:45:00 AM


Ryerson professor Russell Richman; and Ekaterina Tzekova and Kim Pressnail of U of T 
Ryerson professor Russell Richman; and Ekaterina Tzekova and Kim Pressnail of U of T
Civil Engineering in front of the Toronto home that will be retrofitted with their nested thermal envelope design this winter. (

Currently, space heating is the largest contributor to residential energy consumption in Canada at 60 per cent of the total. Researchers at the University of Toronto and Ryerson University are looking to cut the number down by 80 per cent.

U of T professor Kim Pressnail and doctoral candidate Ekaterina Tzekova (Civil Engineering) and Ryerson professor Russell Richman (Architectural Science) are researching a Nested
Thermal Envelop Design in a house that is constructed to employ zonal heating and will implement the design in a downtown Toronto home, beginning in January 2013.  The nested thermal envelope design has two key components to recycle heat. First, the home is divided into two different zones, the perimeter and the core. The core is the home's main living areas, while the perimeter consists of less-often used rooms. Secondly, the home would have a small heating unit that cycles heat from the perimeter into the core during the winter season. The heat pump then funnels heat lost to the perimeter back into the core of the home before it is lost to the exterior.

"Ordinarily, single-family homes have just one zone," said Professor Pressnail. "Here, by having two envelopes, we effectively create two zones in which heat moisture and air movement can be controlled separately."

Once the nested thermal envelope design is implemented into the Toronto home, the team will elect test subjects to live there, beginning with a member of their research team. Later on, the home will become a residence for visiting professors. The research team will also track behaviour patterns and get feedback from the occupants over the next five years.

"The biggest advantage is when energy prices go up or there are interruptions in the supply, it only takes a small amount of energy to keep homes comfortable," added Professor Pressnail. "Further, this isn't just about saving energy - it is about reducing our burden on the environment."

The project is funded by the Ontario Power Authority's Technology and Development Fund and the University of Toronto.

U of T faculty, staff and students can view an article on their preliminary findings in the November 2012 issue of Energy and Buildings.

This is an edited excerpt of an article found at