Residential retrofits: saving energy and money. (Technology).

Saskatchewan families can do their bit to conserve energy and save money while they are at it. That's the conclusion of a three-year study of energy retrofits on five Saskatchewan residences.

The study found that families can save up to 40 per cent or more on their natural gas and electrical bills by carrying out a retrofit. With payback times as short as 10 years, investments in residential energy conservation are at least as rewarding as returns from GIGs or Canada Savings Bonds.

In Saskatchewan, housing is a significant source of greenhouse gasses that cause climate change, such as carbon dioxide. This is largely due to our cold climate, which requires a lot of energy for space heating. Research shows that the average Canadian home produces 6.5 tonnes of carbon dioxide every year. An effective energy retrofit can reduce carbon emissions by as much as two tonnes.

The goal of the study, carried out for Canada Mortgage and Housing Corporation, was to see if it is feasible to achieve 40 per cent reductions in energy consumption at a cost that the average family might be willing to take on. Five houses of differing styles and ages were chosen and detailed energy audits were carried out. Based on computer models, the consultants then provided the homeowners with retrofit strategies that spelled out the most cost-effective ways to reduce energy use.

The best energy savings resulted from installing energy-efficient furnaces, improving airtightness, upgrading appliances, improving attic and other insulation levels, and the use of compact fluorescent lamps. Energy-efficient refrigerators or freezers, for example, have been found to reduce energy consumption by 75 per cent compared to older appliances. During the course of the project the compact fluorescent lamps available on the market improved in quality and decreased in cost, thereby allowing for extensive use by the homeowners.

Weekly utility meter readings were performed in the postretrofit period (for more than a year), concluding on December 31,2002. For the pre-retrofit period, utility readings were obtained from the local utility companies. Results comparing the pre- and post-retrofit periods show that for the five case houses natural gas consumption declined between 25.9 to 45 per cent and electricity consumption declined between 2.4 to 40.8 per cent.

As weather during the test period could deviate from historical temperatures, five control houses were also found for the project. Energy retrofits could not be carried out on these homes during the three years of the project. Regular monitoring of the utility meters in these houses and graphing of pre- and post-retrofit energy consumption was done over approximately the same time period as the five case houses.

Results from the control houses showed that gas consumption between the pre- and post-monitoring period increased by 7.7 per cent due to more severe weather. Therefore, the decline in total energy consumption of the case houses, when corrected using control house results, varied from 26 per cent to 39.6 per cent in the individual homes.

The retrofits, which were carried out at the homeowners' expense, cost an average of $7,000. Three of the five homes will be able to recoup their investment in approximately 10 years from savings on energy bills. Two of the homes will take more than 20 years to recoup costs, due to lifestyle changes, incomplete implementation of the retrofit recommendations, and low initial energy consumption. Return on investment for energy retrofits compare favorably with conservative investments like GICs and bonds, considering current interest rates.

For the Saskatchewan business community, energy retrofits may represent a significant market, given that Canada's climate change plan calls for energy-efficient retrofits of 20 per cent of the country's housing stock and 20 per cent of its commercial/institutional building stock by 2010. Awareness of the cost effectiveness of energy savings should create significant buy-in from Saskatchewan homeowners.

Tam MacDermott is an Associate Research Engineer with the Saskatchewan Research Council's Building Performance Section.