When most people think of skylights, they may not be focusing on energy efficiency. The most notable feature of a skylight is simply natural light. Technology still hasn’t provided an artificial equivalent for the aesthetic and mood-lifting benefits of sunlight streaming downward into living spaces from above. While windows allow indirect light into the house laterally, an overhead skylight provides the most direct way to gain the beneficial exposure to real sunlight indoors.When it comes to efficiency issues, however, a residential skylight presents both good news as well as downsides. Here are some skylight pros and cons:
Energy Efficiency Benefits
Extra heat in winter. Sunlight passing through glass carries heat energy along with it that warms rooms and helps reduce furnace expenses during daylight hours. Energy costs can be reduced during the heating season.
Free lighting. During daylight hours, a skylight reduces dependence on other electrical light sources.
Passive ventilation in summer. Skylights that are openable permit enhanced cross-ventilation by letting out rising warm air that naturally accumulates at the ceiling. This upward flow of air creates a “stack effect” in a room that continuously exhausts heat through the open skylight while pulling in fresh air through open windows.
Energy Efficiency Drawbacks
Heat gain on summer days. Solar heat entering through a skylight in summer may cause your air conditioner to run longer to compensate and increase energy costs. Placement of a skylight—such as selecting the north-facing side of the roof with less solar exposure—can reduce heat gain.
Nighttime heat loss. Once the sun goes down, glass in a skylight may allow indoor heat to radiate out of the house into the colder outdoors. In winter, this may require more heat from your furnace to compensate and energy consumption may rise. Skylights that utilize glass with low-emissivity coating can help reduce heat loss in winter.
If you're considering installing a skylight, ask the professionals at Air Assurance for more information about the potential energy efficiency pros and cons.
Our goal is to help educate our customers in the Tulsa and Broken Arrow, Oklahoma area about energy and home comfort issues (specific to HVAC systems). For more information about other HVAC topics, call us at 918-217-8273.