Materials, Specification and Economic Implications of Moving to Carbon-Neutral Housing

Although a UK trajectory toward zero-carbon development for all new housing by 2016 has been set, the cost of building such homes and the changes implied for current constructional culture, together with lack of fiscal incentives, makes the target very difficult to achieve. Moreover, the recent governmental clarification of the definition of zero-carbon housing may make it impossible. This paper proposes a prototype construction (see also the associated paper in this issue) and examines in detail both the constructional and cost barriers to eliminating carbon emissions from tightly limited total thermal and electrical consumption targets (not more than 70 kWh/m2). Having established generous access to sunlight and daylight as prerequisites, a related health issue is air quality, especially with air-tight construction. While thermal and hygroscopic capacity can mediate between quality and efficiency, current norms for Scottish housing are notably poor in both respects. A key aim is to assess whether specification for a ‘low-carbon house’ can be cost effective. An analysis is undertaken to asses the increased cost associated with integration of energy efficient measures in the proposed prototype model. The specification of the building envelope and associated renewable technologies are addressed with reference to their cost implication on the overall build cost. Finally potential governmental incentives are proposed to not only meet the 2016 target, but also to promote enthusiasm by the end user. The paper concludes that low-carbon and zero-carbon scenarios would require radical changes of funding/fiscal and building cultures.