It has long been known that residents use about 30 per cent less energy when they pay for what they use, in contrast to those whose energy bill is included in their rent as a flat rate. Fixed energy bills are like buffet restaurants, where nearly everyone eats more compared to à la carte menus – simply because there is no direct monetary cost.
However, until now, it wasn’t clear how people in submetered homes, where residents pay by kilowatt-hour, were accomplishing energy savings. Burak Gunay, a PhD student in Civil and Environmental Engineering, and Profs. Liam O’Brien and Ian Beausoleil-Morrison recently published their findings on this topic in the Journal of Building and Environment. Gunay led the project by installing temperature loggers in 40 Ottawa apartments, 20 of which were submetered. The other 20 were bulkmetered homes, where residents have a flat energy rate or where the cost was included in rent. Gunay hypothesized that submetered apartments would be kept colder in an effort to reduce heating energy use. But after the two-winter study, they could not have predicted such a big difference between the groups: submetered homes were on average 2.5 degrees Celsius (19.5 versus 22.0 degrees Celsius) colder than bulkmetered homes.
The researchers also interviewed participants to better understand how occupants adapt to the billing scheme. People who pay for their heating usually wear more clothing to allow colder indoor temperatures. In many cases, residents exercise measures to the maximum limit of comfort and practicality, such as lowering the thermostat setting prior to departure and only heating the occupied portion of their dwelling. Industry partner Priority Submetering Solutions, a company that provides submetering services to homes, played an integral role in the study by providing energy data.
The study identified one of the lowest hanging fruits for reducing energy use in Canada. Residential energy represents about 15 per cent of Canada’s total energy use, yet about a quarter of Canadian households remain bulkmetered. Many property management companies are reluctant to upgrade to submetering because the premiums tenants are willing to pay for an all-inclusive price scheme tend to exceed their average incremental energy use. However, landlords remain vulnerable to increases in energy prices which are outpacing the legal rent increase rate by a significant margin.
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