This thesis explores energy efficiency in space heating for new single-family detached mass-market houses in two locations— Regina, Saskatchewan and Vancouver, British Columbia. The study is based on the premise that the energy efficiency of new housing is insufficient given its long life-span and the uncertainty of future energy supplies. The study investigates the process by which housing consumers, builders, government housing programs and regulations interact, in order to understand the obstacles to achieving greater energy efficiency. Seventeen builders were interviewed in Regina and Vancouver together with architects, building inspectors and other individuals closely related to the housing industry. The thesis begins by outlining the problem and justifying the method of investigation. Chapter Two briefly describes Canada's energy context, establishes a need for greater energy conservation, and examines government energy efficiency regulations and other initiatives to encourage greater energy efficiency in new housing. Chapter Three describes the techniques available to the mass-market builder for improving the energy efficiency, of the building envelope and briefly explains some passive solar design options. Chapter Four reviews the economics of residential energy conservation from the perspective of the consumer. Cost-effectiveness analysis and its limitations are described and costs and payback periods are approximated for the techniques detailed in Chapter Three. The chapter concludes with an account of the economic constraints to increasing energy efficiency in new housing. Chapter Five briefly explains the important attitudinal and regulatory barriers to energy efficient housing. Chapter Six examines the energy efficiency standards of the builders interviewed, their responses to key questions, and discusses the major issues that arose from the interviews. The final chapter outlines the major findings of the thesis, and on this basis attempts to justify government intervention to overcome the market inadequacies uncovered in the investigation. The study found that in the absence of strict government regulation of energy efficiency standards in the housing industry, builders have built to standards reflecting consumer preferences and awareness of energy efficiency which have been influenced by energy prices, government information programs and climate. Regional variation were encountered in that consumer demand was a weaker factor in Vancouver while a more severe climate and more active government participation in Regina has created a greater energy consciousness among consumers and builders. Certain builders in each location were responding to an increased energy awareness by building to higher standards than those prevalent in the market, thus acting to direct future consumer demand. The study uncovered several market inadequacies, economic constraints, social and attitudinal resistances, and government policy shortcomings currently inhibiting greater energy efficiency; among them: 1. The value of energy conserving features does not appear to be recognized in the resale housing market. 2. Projected periods of ownership for new home purchasers are less than five years and in the absence of proven resale value these purchasers are dependent on recovery of energy conserving investment through energy savings within this short period. 3. Strict government regulation of energy efficiency has been absent or so lax as to be an insignificant factor in raising energy efficiency standards. 4. The two determinants of housing energy efficiency, builders and consumers, are lacking information on energy conserving techniques and investment required to make informed choices. These problems, the special nature and long life-span of residential buildings, the consequent broader social welfare goals to be achieved by conserving an essential resource, and the need to protect the economic interests of future homeowners, make the energy efficiency of new housing a special case. As a result, the study argues that there is justification for a comprehensive program of government intervention. / Applied Science, Faculty of / Community and Regional Planning (SCARP), School of / Graduate