The space heating and water heating energy demands of the aged in the United States was investigated using the discrete/continuous method. It was found that the aged require more natural gas and fuel oil but less electricity for space heating. The space-heating energy requirement increases as the aged becomes older. Those persons more than 80 years old use not only more natural gas and fuel oil but also more electricity for space heating. This evidence implies that any market strategy for attracting the aged must be tied to their space heating requirements. In contrast to space heating demands, water heating energy consumption is significantly lower for the aged. This consumption rate becomes lower as the aged become older. This may be due to the less active life of the aged. As the proportion of aged persons increases, more social care and activities for the aged should be developed and planned early.