The best direction for a residential building in a community is typically the one that maximizes solar exposure and minimizes exposure to harsh weather conditions. In the United States, the ideal orientation is generally to the south, with the building's longest axis aligned east-west. This orientation allows for the longest possible daylight hours during the winter months, which is crucial for energy efficiency and comfort. According to the U.S. Department of Energy, southern exposure can reduce heating and cooling costs by up to 30% due to better natural lighting and reduced reliance on artificial heating and cooling systems.

This preference for southern orientation is supported by the geographic and climatic diversity across the United States. In regions with cold climates, such as the northern states, southern exposure ensures that the building receives ample sunlight during the shorter days of winter. Conversely, in warmer climates, southern exposure helps to keep the building cooler by reducing the heat gain from direct sunlight. Additionally, the orientation can also enhance privacy and reduce noise from neighboring buildings.

Data from the National Renewable Energy Laboratory (NREL) indicates that buildings oriented to the south have a lower risk of overheating during the summer months, as the angle of the sun is higher and the solar gain is more diffused. This is particularly important in the southern and southwestern states, where the summer sun is more intense.

Furthermore, the orientation of a residential building can also impact its energy efficiency. A study by the U.S. Green Building Council found that buildings with a high percentage of south-facing windows can reduce energy consumption for heating by up to 50%. This is due to the fact that the sun's energy can be captured and used to heat the building naturally, reducing the need for additional heating sources.

In conclusion, the best direction for a residential building in a community is generally to the south, with the building's longest axis aligned east-west. This orientation maximizes solar exposure, minimizes exposure to harsh weather conditions, and enhances energy efficiency, leading to lower heating and cooling costs and increased comfort for the occupants.