Evaluating computer aided design tools for building performance: Trusting and defining the predetermined automated inputs

BIM use is on the rise in New Zealand with popular software packages, including Revit and ARCHICAD, adopting a semi-automated simulation platform. This allows architects and designers to calculate the thermal and energy performance of their designs. This paper identifies the strengths and weaknesses of these semi-automated simulation platforms. The objective is to investigate how accurate their assumptions are in determining a reliable output for use in achieving compliance with Clause H1 of the New Zealand Building Code. To achieve this, this paper reports a comparative study that examines the program’s ability to calculate construction R-values, interpret thermal properties and simulate energy performance. The results from this study show that if used as delivered there is a significant difference between the simulation results of the two software packages, due to the assumptions built into the default settings. It also identifies the disadvantages of the inbuilt construction R-value calculators and explores a potential path to resolving this through redefining the inputs of thermal properties.