Medium-density dwellings in Auckland and the building regulations

Abstract

National thermal standards have historically been set to minimise winter heating energy in detached houses. It is uncertain whether these standards are optimal for the increasing number of joined, medium-density dwellings when summer and winter conditions are considered. Using freely available software, annual heating energy use and summertime peak temperatures were calculated for a number of versions of detached and joined dwellings offering the same occupied volume and window areas. Initial results indicated that, as expected, the joined dwellings required less heating energy. The detached house exhibited a higher peak summertime temperature but a lower overall average daily temperature. Interventions such as changing insulation, glazing areas and ventilation were calculated to reduce summertime temperatures in the joined dwelling. Increasing ventilation provided the greatest improvement particularly during the sensitive sleeping hours. Changes to clauses H1 Energy Efficiency, G4 ventilation and G6 Airborne and Impact Sound are recommended if these early findings are confirmed in a more complex simulation.

This paper is a longer version of a Building Better Homes Towns and Cities National Science Challenge think-piece commissioned by BRANZ for publication in early 2018