Skylights: More Than Just a Window in the Ceiling

During the 16th century it was very common for large estate homes to have a conservatory as part of the main building. All the walls and ceiling would be constructed of glass in an effort to provide sunlight to (primarily) citrus plants at all times of day. Perhaps the conservatory was the origin for the idea of a ‘roof lantern’, but what is undoubtedly true is the overabundance of condensation, leaks and heat loss prevalent in these structures. Up until the mid-1990’s, the same effects were being experienced in homes with just a simple skylight, let alone a full sized conservatory.

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In the interest of bringing everyone up to date on skylight technology, those who have not seen or been around skylights since the 1980’s are in for a pleasant surprise. Gone are the days of domed panels of plexiglass that seem to amplify every noise within a 20 mile radius. Single paned skylights that weep with condensation when the hot water is on for ten seconds are the dinosaurs of the homebuilding industry wholesale hotel furniture. Those leaky units that marked the drywall and caused the precise placement of buckets during the rainy season are also long gone. Having a skylight in the bedroom no longer means cranking the thermostat to account for heat loss. Yes, the skylight is definitely a different beast than it was 30 years ago. Let’s take a look.

Placement of a skylight is important to its overall performance. The general climate, altitude and type of skylight are of course important factors to consider but the rule of thumb with most circumstances dictates the skylight should equal no more than 5-9% of the floor area. More than the 9% will mean the inability to control the level of temperature transfer from outside. Less than 5% will not significantly impact the indoor area in ambiance, electricity savings or offer useful daytime lighting. To be clear, a skylight is any horizontal window – that is not something installed in a vertical manner which inevitably provides a whole host of other uses and benefits.

Skylights today are no longer domed and single paned. They are double paned, flat and made from thicker more durable glass that has been highly engineered to be energy efficient. The high tech glass is designed specifically to prevent heat loss in winter and retain cool air in summer. Plus, some of the newest features include electric venting which ultimately transform the skylight into a passive air conditioner. Another great feature is the rain sensor, whereby the first few drops of rain on the skylight will cause it to close automatically. What could be more convenient?

A state of the art skylight with all the bells and whistles is not worth very much if it wasn’t installed properly. The glass itself may be energy efficient, but what about the areas immediately around the skylight? Was the unit just nailed in place and caulked around the edges? If it was, that could be a problem. The cavities surrounding the skylight should be insulated, preferably with a closed cell spray foam which has the ability to seek out and fill in every little crack. Spray foam insulation will not only close up all gaps and prevent heat loss, it is also mildew resistant just in case there is some eventual moisture penetration.

On the subject of energy savings, consider the use of daylight instead of an electrical light – especially during the spring and summer months. In a home with many windows as well as a few strategically placed skylights, an electrical light would not be needed for most of waking hours each day. Also, with energy efficient skylights properly installed and insulated, heating and cooling costs can be greatly reduced. In the long term, one could even surmise that the mere presence of these high tech features could increase the overall value of the home and make it more desirable to buyers.

Today, the word conservatory means more than it did during the 16th century, and the word skylight means far more than it did 30 years ago. A conservatory is no longer just a greenhouse, it can also be a music school – and not necessarily one enclosed in glass. A skylight is no longer associated with leaks, condensation and pockets of cold air. Now, in this 21st century world of technical engineering and higher building standards, the skylight is associated with daylighting and energy efficient home design. It isn’t just a window in the ceiling anymore.

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