Skylights can increase the amount of natural light in a home. Consequently, they save on utilities by reducing the use of artificial lighting—even at night.
Nevertheless, skylights come with a few disadvantages. Sometimes they create a greenhouse-like effect and make rooms intolerably warm. As well, a skylight increases the likelihood of leaking. In the least, they need an annual inspection, but scheduling both a spring and autumn check-up is best.
Largely, vented skylights pose the biggest threat. A vented skylight has hinges or tracks so that it can open. This design introduces new opportunities for leaks, including accidental ones like being left ajar in the rain. Conversely, vented products help reduce moisture in the home and can increase the airflow. Said benefits affect both air quality and utility spending.
Of course, skylights that are properly installed and sealed add little risk. Because of how involved the process is to add one, though, many professionals recommend building them during a major roof renovation or installation. Doing so reduces the risk of damaging an existing roof when cutting into its surface and structural components.
Generally, skylights increase the cost of all roof-related projects but not the frequency. Despite common belief, they do not make roofs weaker. Skylights use tempered or laminated glass, making them highly durable. Therefore, things like branches and other debris pose no further threat to a skylight than they do to shingles.