Are Skylights Energy Efficient?

April 2nd, 2020

When installing skylights, the placement and installation can truly make a difference. Not only can the indoor climate of the building and the day-to-day life of anyone in and out the doors be affected, but so can the amount of energy and therefore money can depend on that as well. A perfectly-placed skylight can bring in natural light during the day and even naturally heat what would’ve been a chilly room. To avoid wasteful mistakes, it’s important to make the correct decisions in the early stages of installations to make skylights energy efficient.

1: Consider your location.

Before diving into the size of the skylight (and other details), it is important to choose the best rooms for skylights based on their location. The position of the skylight can strongly affect the heat gain or loss.

In warmer climates, north-facing slopes are best for skylights to ensure that the lowest amount of solar heat sneaks in. In colder climates, south-facing slopes are the smartest. If neither slope is an option, east- and west-facing skylights are generally a safe and more neutral choice.

Choosing the best side of a commercial building based on the location and climate can make all the difference in heating and air conditioning costs in the long run.

2: Consider the skylight’s ratings.

There are two ratings that are very important to know when making crucial skylight installation decisions: (1) the Solar Heat Gain Coefficient (SHGC), and (2) the U-Factor.

The SHGC tells you how much solar heat gain a window or skylight will get, shown as a number less than 1 (the closer to 1, the more solar heat let in through the skylight). In an area that typically has a colder climate, the higher the SHGC, the better. On the contrary, an area in the south where it is typically hotter year-round, a lower SHGC is more suitable.

The U-Factor rates window insulation. The lower the number, the harder it is for heat flow to travel through a window. The average U-Factor for windows is roughly 0.20 to 1.20 (though it can range farther than that as well).

Learn more about SHGC and U-Factor here.

3: Consider the size of the room.

The size of the skylight compared to the room’s total area is an important factor to think about before installing a skylight. The Department of Energy recommends a maximum size skylight of 5% of the room’s total area if the room already has other windows installed. If the room doesn’t have windows, you may go as high as 15%.

4: Consider who is installing it.

The most important decision when installing skylights is the company you work with. Look to work with a company that wants to help make the best decision for you, your workspace, and your budget. A company that does these things in more results in high-quality skylight installation.