As a result of a survey of the potential needs of consumers for window insulation, it was clarified that the information that motivates retrofitting differs depending on the attributes of the household (age, the presence or absence of housemates, etc.), and it is important to disseminate meticulous information. Overall, it was also clarified that there was a lack of information on how comfort is improved and that there were barriers against carrying out heat insulation retrofitting such as costs, labor, and insufficient motivations. Furthermore, the CJT analysis revealed the hidden demand of consumers to ensure the improvement of comfort, which led to the result that the "constructor reliability" and the "real experience" became more effective. From the above results, it was concluded that the "government's official approval system for constructors" and the "installation of window insulation experience showrooms" are effective measures to promote the spread of window insulation retrofitting in detached houses. It was quantified that if these measures were implemented, window insulation retrofitting implementation would increase significantly.