Many people who live in rural areas with low disposable income are unable to acquire clean energy. This means that they are exposed to respiratory diseases and are more likely to encounter unbearable healthcare expenditures. But when stakeholders are responsive, they create a healthcare system that offers affordable and accessible and encourages the use of clean energy. When health care expenditure is high, many poor households struggle to access the services, particularly for households not covered by health insurance. Therefore, the current study sought to examine the moderating role of income on the relationship between domestic energy options and healthcare expenditure. The study used a cross-sectional research design and collected data from a random sample osf 384 households from Kisii County. The data was collected using a structured questionnaire. Data was analyzed using descriptive and inferential statistics. Findings show that most of the households were earning less than Ksh. 30,000 a month. Similarly, more than two-thirds of the households relied on solid biomass including firewood and charcoal for cooking. Findings show that domestic energy options have a significant relationship with healthcare expenditure for households in Kisii County. However, income does not moderate the relationship between domestic energy options and healthcare expenditure. The findings help policymakers to improve the uptake of clean energy options among households by subsidizing the cost of clean energy or removing tax on the products. The findings also encourage the uptake of universal healthcare among poor populations to reduce incidences of catastrophic healthcare expenditure.