Conducting a building thermal efficiency retrofit (or further thermal retrofit) is a long and relatively complex decision-making process involving building owners, managers, residents/tenants, and construction industry professionals. A variety of information instruments exist to support participants at each stage of this process. This paper highlights the existing literature on information instruments used in Germany and elsewhere, describing the role that they can play during different stages of the decision-making process. Where information is available in the literature, the paper also discusses effectiveness and implementation practices.