Today, energy simulation tools (ESTs) are readily available being utilised to assist designers (and builders) in achieving energy efficiency targets and fulfilling code regulations. Likewise, the United Kingdom (UK) government recommends the use of the Standard Assessment Procedure (SAP) for energy rating of dwellings. In order to facilitate the assessment procedure, the National Energy Services developed a SAP- based simulation software tool called ‘NHER Plan Assessor’. Despite the usability, or ease of application, its accuracy tends to be questioned in view of the limited sources of energy use and climatic condition applied to SAP simulation. Today, a number of similar tools are applied around the globe—e.g. Passive House Planning Package (PHPP) and HOT2000. Unlike the UK’s SAP simulation tool, PHPP and HOT2000 have widely been applied to domestic energy simulation beyond their countries of origin—i.e. Germany and Canada, respectively. This study was aimed mainly at demonstrating a way to compare the usability of these ESTs in the design decision-making process. The comparative performance study was carried out using an existing housing prototype called ‘ZEMCH 109’ in Prestwick, Scotland. This paper identifies the significance of ESTs’ information management, agility and adaptability and the correlation to the design decision-making stages, which affect the energy performance of housing. Further investigation on the application of weight evaluation approaches to criteria identified was recommended in this study.