Skylights In Winter: How To Minimize Heat Loss

heating lightBy channeling the sunlight, skylights serve as a source of natural illumination; providing  significant health benefits as well as being pleasing to the eye. However, some home owners may be concerned about the risk of heat loss and leaks during winter.

According to, a skylight located in the roof loses 35% to 45% more heat during winter than a window positioned on the side of the house. This is mainly due to two factors:

– Convection: As we all learn in science class, hot air continuously rises. If there is a skylight in the roof however, the hot air is cooled by the contact with its surface before sinking back down again

– Radiation: Whereas windows are usually protected by trees and such, skylights have only the endless depths of the night sky above them. This lack of shielding means that much heat will be lost through radiation.

These issues are exacerbated by the fact that most skylights have a very large surface area, allowing more room for heat loss.

However, with a little preparation and planning, you can ensure that your skylights are well-equipped to handle the cold winter months.

Preventing Heat Loss

Anyone looking to install skylights will be pleased to know that modern designs  are much more efficient when it comes to regulating heat loss (as well as heat gain, which can be a concern during the summer).

One way in which they achieve this is through special low-emissivity film coverings. Though these might bring about a slight reduction in light, they are effective at blocking heat transmission.

Thermochromic coatings can also be applied, which are able to alter the appearance of the glass in response to the amount of heat making contact with its surface.

Other ways in which you can ‘winterize’ your skylights include:

– Positioning: The location of the skylight on your roof affects how much heat and light it will collect at certain times of the day, and during certain seasons. South facing skylights are best suited to winter, though they will contribute to heat gain during the summer. One way to balance it out is to ensure they are shaded by trees during the summer. These trees will then lose their leaves during the winter, allowing the skylight to gather more heat.

– Slope of the Skylight: The angle of the slope, combined with the position of the sun in the sky, affects the amount of heat that is able to pass through the skylight. A good rule of thumb is to ensure that the slope is equal to your geographical latitude plus 5 to 15 degrees.

– Ventilation: High levels of humidity in the upper areas of your home, usually caused by laundry rooms or bathrooms on the upper floor, can bring about increased condensation. Ensuring adequate attic ventilation can help prevent this.

Tubular Skylights: These are able to channel sunlight through tubes that run from the roof to the various rooms. As such, they are less susceptible to heat loss, as well as being cheaper to install.

Preventing Leaks: Positioning the skylight on a raised surface, slightly above the roof, can help prevent leaks. Regular inspections should be conducted to identify any damage done to the skylight by weather conditions or fallen branches.

Special glazing materials like those mentioned above may increase the cost of installing the skylight, but they reduce costs elsewhere. According to, winterizing your home can save as much as 30% in energy bills.

Furthermore, they ensure that the home owner can enjoy the financial, aesthetic and health benefits of skylights, without having to worry as much about the detriments.

Matthew Flax is a freelance writer who feels duty-bound to warn you about the risks that winter poses to your skylights, which kind of makes him the Ned Stark of the skylight world.

Posted in DIY