This unit of competency specifies the outcomes required to explain to clients the principles of residential building thermal performance. This includes explaining the process of heat transfer in residential buildings; the factors that impact on thermal comfort; how climatic conditions, building design and materials influence the thermal performance of residential buildings; and the principles of passive design.The unit supports the work of Nationwide House Energy Rating Scheme (NatHERS) assessors engaged in providing information on residential buildings’ thermal performance.In some jurisdictions, this unit of competency may form part of the accreditation, licensing, legislative, regulatory or certification requirements for NatHERS assessors.