Household solar energy products represent a rational and increasingly prevalent trend in modern life. Research on customers’ adoption processes of such products is essential, as their decisions are influenced by numerous factors. This study examines the determinants and outcomes of customers’ intention to use household solar energy products by extending the TPB framework. Primary data were collected through structured questionnaires administered to 250 Vietnamese households regarding their use of rooftop solar systems, and analyzed using SPSS and AMOS software. The results align with the TPB framework and its extended constructs. The results reveal that several factors significantly influence consumers’ behavioral intentions and payment preferences regarding household solar energy products. Specifically, attitude, subjective norms, perceived behavioral control, green moral obligation, and environmental concern all have significant positive effects on the intention to use such products. In contrast, perceived cost of use demonstrates a significant negative relationship with the intention to use, suggesting that higher perceived costs may discourage adoption. Moreover, intention to use exerts a significant positive influence on willingness to pay, indicating that as consumers’ intention to adopt solar energy products strengthens, so does their readiness to invest financially in them. This study enriches the existing literature on household solar energy adoption by providing insights from the consumer perspective, and the proposed framework offers a valuable basis for future investigations into consumer behavior within the solar energy sector.