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Home Improvement : Shedding Some Light on Installing Skylights

January 06, 1991|JAMES DULLEY | Dulley is a Cincinnati-based engineering consultant

QUESTION: We don't have cathedral ceilings in our house, but we want to put skylights in our kitchen and bedroom for more natural lighting and for live plants. Is it still possible to install a skylight?

ANSWER: It is common practice to install a skylight in a room with a flat ceiling and pitched roof above. You must construct a light well from the skylight on the roof down to the ceiling. The construction methods are fairly simple, but you must pay close attention to detail or the lightwell/skylight can become a big energy waster.

In the initial design phase, you should plan on a light well that tapers out from the skylight to a larger opening in the ceiling. Otherwise, the light tends to get trapped and absorbed in the lightwell, reducing its effectiveness.

It is extremely important to properly size the skylight for the room size. If it is too large, there will be excessive winter heat loss, summer heat gain and possibly glare. If it is too small it will not provide adequate lighting, and you will still need electric lights.

You should select a super-high-efficiency skylight. Triple, Heat Mirror, or low-emissivity ("low-E") with argon-gas glazing are the most energy-efficient year-round. Low-E also helps block the sun's fading rays.

During the spring and fall, and if you don't air-condition in the summer, a venting skylight in a light well can provide excellent natural ventilation in addition to light. Since the well gets warm from the sun, it creates a natural upward draft to ventilate the room without fans.

You can easily build the lightwell frame, connecting the opening in the ceiling to the hole in the roof, with standard lumber. Build doubled roof rafters and ceiling joists for support. Attach short cripple studs on the sides to hold the finished wall and insulation. For maximum lighting, paint the inside of the lightwell white.

Insulate the sides heavily, just as you would the ceiling. Rigid foam insulation sheets are very effective. They provide high insulation value per inch thickness, and they are easy to install in the more-vertical position.

You should install an inexpensive reflective-type roller shade under the skylight to reduce the summer heat and glare at midday. You can leave it open in morning and afternoon, when the sun shines in at a lower angle.

Write to me for Utility Bills Update No. 110 showing simple do-it-yourself instructions and a diagram for building a skylight lightwell, a chart showing recommended skylight sizes for various room sizes and a list of manufacturers of new super-high-efficiency skylights. Please include $1 and a self-addressed stamped business-sized envelope. Send your requests to James Dulley, c/o Los Angeles Times, 6906 Royalgreen Drive, Cincinnati, Ohio 45244.

Those Little Fish Can Be Kilowatt Hogs

Q: I had all the electrical appliances and lights turned off the other day, and the wheel in my electric meter was still spinning pretty fast. Does my aquarium use much electricity?

A: An aquarium can be a significant consumer of electricity. It has an electric heater, air pump, and intensive lighting that run many hours each day. A typical 20-gallon aquarium can use several hundred kilowatt-hours of electricity each year. In an efficient house, this accounts for a substantial amount on your electric bills. A large aquarium can actually use more electricity than an efficient refrigerator.

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