problems with skylights

Skylights aren’t only a source of light or natural ventilation and views. They may also be an unwanted source of heat losses or solar gains, infiltration and moisture. Do not neglect possible drawbacks, when selecting and installing skylights.

Condensation

Well installed and efficient skylights are virtually immune to condensation problems. Better skylights may have interior channels to collect the condensation water, which can be evaporated later.

You just have to buy good energy-efficient skylights and have them properly installed. Avoid cheap plastic skylights, and pay attention to installation. Without a proper installation even the best skylight can cause condensation problems.

Heat Loss Problems

Modern manufacturers use modern technologies to reduce the heat loss and the inopportune solar heating associated with traditional skylights. These technologies include special glasses (double glazing and triple glassing and low-emissivity coatings) and heat-absorbing tints (see: Solar films).

Traditional skylights, without proper low-emittance glasses are prone to huge heat losses during cold weather (higher than those caused by windows). To avoid this problem, skylights should incorporate modern energy efficiency options, namely low-E glasses panes, filled with argon or other gas.

Skylights made with plastics, and skylights with a dome and ridge design are typically inefficient, and cannot incorporate energy-efficient technologies. Avoid cheap skylights, and pay attention to their rating (prefer Energy Star or other official labeling) to avoid heat loss problems.

Inopportune solar heating and UV ray damage

Skylights are typically highly exposed to hot sun, which may result in a high solar heat gains at inopportune times. Besides, traditional skylights also can cause UV ray damage to carpets or furniture.

A careful location of the skylight and a strategy involving trees and their shade, may minimize this problem. But in many situations the problem can be handled differently, namely through the using of tubular skylights or selecting smaller traditional skylights (skylights have not to be large to driven large amounts of daylight) with very low-E/spectrally selective glasses. See: Skylight glasses.

Another indirect way to face this problem is to consider skylight blinds, awnings and shades.

See:

The skylight size and installation
Skylight Buying and Selection
Skylight blinds, awnings and shades

Infiltration

Natural ventilation is a major goal associated with traditional roof skylights. These skylights can be opened during warm periods, allowing the home’s warm air to rise toward them and escape, with the resulting cooling.

But the inverse may also happen. Traditional rectangular skylight surfaces can cool the air that rises to them. Besides, improperly installed skylights are especially prone to air infiltration through spaces between their glazing and frames.

The only way to avoid these potential drawbacks is high quality skylights, and a very careful installation.

See:

Skylight Basics
Installing Flat Rectangular Skylights
Sun Tunnel Tubular Skylight Installation
Roofs, ceilings and skylights
Skylight Location