Glass Vs Acrylic Skylights

As usual there isn’t a standard choice for determining which skylight is best. You’ll need to know the variables and make your own choice as what works best for you and your home.

First consideration is what is the pitch of your roof? Or in layman terms is your roof slanted or is it more flat? Typically if your roof has less than a 3/12 pitch you’ll probably want to stay with an acrylic dome skylight. However, you can build your curb that holds your skylight at a slant, if you really prefer a glass skylight. This way water will roll off the glass, pulling most of the dirt with it.

Other considerations are:

1. The cost. Custom glass skylights cost more than custom acrylic skylights however, with the Velux FCM Models you’ll find that cost is nearly the same.
2. The view. Glass skylights have a near perfect image. Acrylic, by the nature of the product can have a wavy look to the view.
3. Durability. Glass has factory seals that are warranted for twenty years by the better quality manufacturers. Acrylic needs to expand and contract and this can wear out the gaskets that hold the acrylic in its frame. Poorer quality acrylic can become brittle and yellow.
4. Survivability. Tempered glass tends to survive punishment better than acrylic. Glass has to have its edges protected inside a sturdy frame and can survive most hailstorms. Acrylic will not hold the same weight as glass can.
5. Design. Most acrylic skylights are 1980’s design technology. The better ones will have thermal break aluminum frames, however glass can be installed in the same frames. Many manufacturers of aluminum framed skylights drill holes in their condensation gutters to allow the water to weep out. However, this lets cold air in that causes condensation. Catch 22! Velux FCM skylights are 2000 design technology and don’t have aluminum on the inside so you don’t have to worry about heat/cold transfers or condensation.
6. Appearance. Glass is flat and tends to look nicer than the domed acrylic skylights. Also, noise is deflected off glass better and keeps the interior of your home quieter.

In summary, my opinion from twenty-five years of experience, glass skylights are better.