Basking in the light of a sunny day can make you feel warm and rejuvenated. Bring that experience into the darkest nooks of your home with a skylight or sun tube. Natural light is easier on the eyes for reading and household tasks and may slow the growth of mold and mildew. A house suffused with light is also more appealing to buyers and can substantially increase its resale value.
Skylights
When you shop for a skylight, you will quickly realize there are many choices. The first is shape. Most people install a rectangular skylight, but you can also choose a circular, oval, diamond, triangle or multi-sided shape.
The glass or plastic infill of a skylight, referred to as glazing, also comes in a variety of options such as flat and “warped plane” (flat on the bottom and concave at the top). But the arched, domed and pyramidal shapes offer the most flexibility when it comes to where on a roof they can be placed. They also don’t catch debris and water as much as the flat designs. Flat skylights on low-sloped or flat roofs may need extra framing for proper drainage.
Glazing is usually plastic or glass. Plastic is less expensive than glass and isn’t as breakable, but it does scratch more easily and with time may become discolored and brittle. Glass is more expensive but more durable. Triple-glazing -- installing three layers of glass -- is the most expensive but provides the best insulation. Consider choosing a glazing that blocks ultraviolet rays and prevents damage to your furniture.
The larger the skylight, the more light it lets in, but it will also add more heat to the space. In rooms with many windows, skylights shouldn’t be equal to more than five percent of the floor area. They shouldn’t be above 15 percent of the floor area in rooms with few windows. You should also ask a roofer whether you will need to retrofit your roof to compensate for the added weight.
If you are putting your skylight in a bathroom or kitchen, you may need to buy one with ventilation. There are many options, from a manual vent you can open with a pole, to a moisture-sensitive device that closes automatically.
Because skylights are prone to leaks, make sure your contractor or roofer installs the correct type of flashing for your roof. Also make sure all joints are sealed, and it’s a good idea to install a curb-like lip around the perimeter to deflect water. Sheet waterproofing, which adds a layer of material around the skylight, may also be useful to help stop water leaks.
Insulation is important to prevent heat loss, but also keep energy efficiency in mind when selecting your skylight. Look for the ENERGY STAR label, which indicates that the skylight surpasses the minimum energy performance requirements by as much as 40 percent. Also, look for the orange and blue sticker of the National Fenestration Rating Council (NFRC). ENERGY STAR bases its ratings on the NFRC’s U-value (how much heat is transferred). U-values range from 0.20 to 1.20, with the most energy-efficient earning the lowest rating.
Skylights may add to your energy bills in the summer because, depending on placement, they may channel the sun’s heat into the room. This can be alleviated some by installing a skylight on the north side of a roof, under the shade of a tree or by installing a window blind over the skylight.
Efficient skylights also help prevent condensation that collects on the glazing and may drip into a room, a common problem in colder climates. This may necessitate the installation of a device to collect the water.
Skylights cost between $100 and $300 for a low-budget model with plastic glazing, and high-end models run $1,000 and up for custom shapes with insulated glass. Installation is extra.
Sun tubes
A sun tube, or tubular skylight, has a dome-like lens jutting out from the roof that is connected to a reflective tube that funnels light through the building and then diffuses the light into the room below.
Sun tubes are much smaller than skylights (usually between eight and 12 inches in diameter), so they can be placed in some of the smallest -- and darkest -- areas of your homes, like a bathroom, hallway or walk-in closet, even if they don’t have direct roof access.
They are less expensive, costing $200 to $600, and they probably can be installed by a handy do-it-yourselfer in a few hours. Sun tubes usually don’t have the problems associated with traditional skylights because their small, round shape doesn’t collect water and debris. However, sun tubes may still require additional insulation around the tubing to be as energy efficient as possible.
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