Breaking the heating barrier - Learning from the first houses without conventional heating

When a house can be designed to require less than 10 W/m(2) of heating capacity to maintain 20 degreesC by -10 degreesC ambient conditions, a conventional heating system (i.e. a gas fired furnace, circulation pipes and radiators) can be omitted and total energy consumption drops to a small fraction of normal levels. The result is a drastic reduction in both operating costs and environmental impact. This performance has been achieved in numerous demonstration projects in Europe, including whole developments of detached and row houses as well as apartment buildings. The goal now is to penetrate the broad housing market. This is hindered by often higher construction costs. The challenge is, therefore, to better understand which design features and components contribute the most to achieving such high performance housing, and which measures can be omitted or substituted. Experience has led to a specific set of requirements which the building envelope and technical systems of a house must satisfy. However, these requirements must be fulfilled under different boundary conditions than those for conventional houses, making decisions less than obvious. Five building projects are presented here as examples of successful solutions and these are cross compared. Finally, an outlook is offered regarding what approaches and features will survive in this emerging, next generation of housing. (C) 2004 Elsevier B.V. All rights reserved.