Which action would most likely increase the energy efficiency of a home?

Repairing caulking on windows is a crucial action for increasing the energy efficiency of a home. Caulking is essential for sealing gaps and cracks around windows where air can escape or enter. When these openings are sealed properly, it helps to maintain a consistent indoor temperature by reducing drafts and heat loss during colder months or heat gain in the summer. This not only enhances comfort within the home but also reduces the energy required for heating and cooling systems, leading to lower energy bills and less environmental impact.

While installing energy-efficient appliances does contribute to overall home energy efficiency, the immediate impact of repairing caulking specifically addresses air leakage, which is a critical factor in a home's energy dynamics. Energy-efficient appliances typically save energy during operation but do not directly influence air sealing or insulation. Incandescent light bulbs are less energy-efficient compared to LED or compact fluorescent bulbs, and leaving attic vents uncovered can lead to energy loss and inefficiency by allowing conditioned air to escape.