Colliding sea surface waves generate the ocean microbarom, an acoustic signal that may transmit significant energy to the upper atmosphere. Previous estimates of acoustic energy flux from the ocean microbarom and mountain/wind interactions are on the order of 0.01 to 1 mW/m2, heating the thermosphere by tens of degrees Kelvin per day. We captured up going ocean microbarom waves with a balloon borne infrasound microphone; the maximum acoustic energy flux was approximately 0.05 mW/m2. This is about half the average value reported in previous ground-based microbarom observations spanning eight years. The acoustic flux from the microbarom episode described here may have heated the thermosphere by several degrees Kelvin per day while the source persisted. We suggest that ocean wave models could be used to parameterize acoustically-generated heating of the upper atmosphere based on sea state.