In Japan, households are responsible for 21% of total greenhouse gas emissions. Notably, it is possible to substantially reduce carbon dioxide (CO₂) emissions by guaranteeing household energy self-sufficiency. Therefore, the authors integrally developed housing components such as photovoltaic power generation systems, storage batteries, air conditioning and ventilation systems for all rooms, and achieved to create houses equipped with a self-sufficient energy unit that contributes to reduce CO₂ emissions. In this study, we demonstrated in actual houses equipped with a self-sufficient energy unit to verify the reduction of CO₂ emissions and the contribution of convenience and comfortableness for the residents. As a result, it was verified that the CO₂ emission was reduced by 7.00 tCO₂/year compared to general housing as of FY2013. Furthermore, we have verified that we can simultaneously provide user benefits such as good temperature and air quality (the air conditioning and ventilation system for all rooms), convenience of being able to easily operate all the air conditioners in the house and home appliances (using smart app), and security that enable to evacuate at home during disasters (by using strong power supply which is useful in a power outage).