Daylighting and Heat: Myths and Misconceptions

Daylighting and Heat - Myths and MisconceptionsMany homeowners fear that adding a skylight to their home could make it harder to control its temperature. Business owners often have the same concerns, fearing that a skylight or large daylighting installation could make their office or retail store far more costly to cool during the warm days of summer.

These concerns are understandable, and in some cases, quite real. In past decades, many skylights lacked the most basic insulation or protective film, and created an uncomfortable hot and bright environment on hot, sunny days.

While the skylights that caused these effects have been phased out for many years, homeowners and business owners still have quite reasonable concerns. Thankfully, modern daylighting systems address the heat problem using a variety of materials and design features.

Can skylights make a room warmer?

When direct sunlight penetrates into a room, it makes it warmer. This is the case whether light enters through a window, a glass door, or a skylight. However, not every skylight will heat a room during sunny weather, and various factors such as skylight placement and the use of window treatments can affect heat transfer.

Skylights that are positioned properly can let the maximum amount of light into a room without substantially increasing its heat. A skilled architect and daylighting contractor can place skylights and other large window installations to let in light without letting in excess amounts of heat.

There are other factors, which can prevent skylights from making a room too hot during summer. Films can be applied to shade a skylight or diffuse sunlight. Both treatments reduce the amount of heat gain that occurs, making rooms lit by light from the sun feel cooler and far more comfortable during summer.

Want all the light, but not the heat? Bristolite skylights use Coollite – a spectrally selective glazing system – to block 85% of infrared and 99% of ultraviolet light without reducing light transfer. This reduced solar heat and ensures that your building is more comfortable, even at the peak of summer warmth.

Can skylights make a room cooler?

Just like skylights without insulation and window film can make a room warmer in summer, skylights without any form of insulation can make a room feel cooler when it’s cold outside.

Warm air tends to rise to the top of a room, making the ceiling an opportune place for heat to escape. This is why so many homes in cool areas are heavily insulated in the ceiling – because without insulation, large amounts of heat can escape through the roof of the home.

With the right glazing, skylights can prevent heat from escaping. Many skylights are glazed using glass for both durability and heat retention. Using tempered glass as a form of impact protection, many skylights are thick enough to prevent any feat from escaping through the roof of a home, retail store, or commercial building.

Using skylights to control a room’s temperature:

Far from making it harder to control a room’s temperature, skylights can often make it easier. While some skylights are fixed shut, many models can be opened to provide your home, office, or commercial building with a convenient and very effective form of ventilation.

Since hot air rises towards the top of a room, skylights are excellent for reducing the temperature of a room during summer. Opening a skylight allows hot air to escape from a room – air that would otherwise accumulate near the ceiling. Many skylights are easy to open and close, with some using automated control systems.

While the skylights of previous decades may have caused rooms to become too hot in summer and too cool in winter, today’s daylighting systems use a combination of glazing, window filters, and new technology to ensure that your home, retail store, or other business environment remains comfortable in all seasons.

Because of this, you can enjoy the warmth of summer and crisp weather of winter without having to worry about your daylighting system interfering with your air conditioning or interior heating system.

“Image courtesy of Kris Ubach and Quim Roser /”

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