ABSTRACT Compared with traditional houses, zero-energy houses (ZEHs) offer efficient and preferable living environments, e.g., reduced greenhouse gas emissions and lower health risks. Currently in Japan, such houses are not as popular as anticipated and sales do not meet the national government target. Accordingly, household buying process should be investigated to develop policies to encourage the spreading of ZEHs. Therefore, we investigated which factors influenced purchasers’ intentions and behaviors. We based our purchase process modeling on the unified theory of acceptance and use of technology, which includes six constructs, i.e., use behavior, behavioral intention, performance expectancy, effort expectancy, social influence, and facilitating conditions. Our model also considered the effects of the information content buyers obtained and the channels they used on performance expectancy. In our estimation, we used Bayesian structural equation modeling and response from 297 Japanese households. It was found that certain information content and channel combinations, e.g., health aspect information obtained from salespersons effectively enhanced performance expectancy. Although performance expectancy did not significantly facilitate the use intention, social influence and facilitating conditions effectively promoted intention leading to purchase. Our findings contribute to more appropriate information provision strategies and supporting policies to promote the spread of these houses.