To evaluate the effectiveness of using natural energy in wooden houses, this study uses long-term measurements in actual homes to measure the extent to which the outside air load is reduced by solar heating and thermal storage, etc., and clarify the level of energy independence achieved by solar power. In this report, we used annual measurement data from houses located in the city of Fujisawa (Kanagawa Prefecture) to check outside air intake situation and the outside air load reduction effect of the natural energy ventilation system. The results the outside air load of this system is 10944 MJ / year, which is a 40.5% reduction compared to outside air load of 18394 MJ / year due to the direct intake．Roof thermal collection is 2936 MJ/year and reheating･pre-cooling of earth tube is 3842 MJ/year･640 MJ/year． Therefore outside air load was reduced good balance in each outside air intake route.
