Studies show that when people live and work in a well-lit environment, they are happier, healthier and more productive.

Natural lighting can also be another way to save on electricity, since it provides free light and warmth. This design technique is called daylighting.

Daylighting is the practice of placing windows or other openings and reflective surfaces, so that during the day, natural light provides effective internal lighting.

It makes sense why daylighting is becoming an international trend.

Natural light lifts spirits, makes spaces appear larger and lessens demands on electricity. Natural light also has been shown to reduce eyestrain and increase productivity.

In short, people function better in light-filled environments.

You can bring light into even the darkest nooks of your home with properly placed skylights and solar tubes.

First consider your home's design and the climate in relation to the energy performance of your skylight.

Look for an Energy Star label to assure you are selecting an energy-efficient skylight. But even with a high-performance rating, a skylight can be ineffective if the placement is wrong within the overall design of your home.

Skylights on roofs that face north provide fairly constant but cool illumination. Those on east-facing roofs provide maximum light and solar heat gain in the morning.

West-facing skylights provide afternoon sunlight and heat gain. South-facing skylights provide potential for desirable winter passive solar heat gain greater than any other location, but they often allow unwanted heat gain in the summer.

You can prevent unwanted solar heat gain by installing the skylight in the shade of deciduous, or leaf-shedding, trees, or by adding a movable window covering on the inside or outside of the skylight.

Some units also have special glazing that can help control solar heat gain.

The physical size of the skylight has an impact on the illumination and temperature of the space below.

As a rule of thumb, the area of the skylights should never be more than 5 percent of the floor area in rooms with many windows and no more than 15 percent of the room's total floor area for spaces with few windows.

Skylights are available in a variety of shapes.

The most common include rectangular, circular, oval, diamond, triangular, multisided and tubular.

Typically, non-rectangular skylights use plastic glazing instead of glass. Plastic glazing, most commonly acrylics and polycarbonates, is usually inexpensive and less liable to break than most other glazing materials.

However, these plastic surfaces scratch easily, and they may become brittle and discolored over time. Plastics also let in more UV rays, increasing fading damage to furniture.

Installation costs also increase with any shape that is not square or rectangular.

Skylight glazing can be flat, arched, domed, pyramidal or warped plane, which is flat on the low side and concave on the high side.

When the shape is sloped or curved, it allows light to enter from more extreme angles.

The raised designs also help shed moisture and leaves. You can choose clear or opaque skylight glazing, depending on whether you want a view of the sky or just added light.

In addition to adding natural light and heating, skylights can be operable, meaning that they can be opened and closed, either manually — usually with some kind of pole that allows you to reach the crank mechanism — or electrically.

If operated electrically, you can even have a moisture sensor installed that will automatically close the skylight with rain. In any case, an operable skylight can be used for moisture control and venting your home.

Skylights are often sized to fit between the rafters or trusses of your roof, which makes installation easier and less expensive.

Larger units that require a revision to the structure of your roof will obviously engender the added expense of engineering and reframing the roof.

Tubular skylights can be an effective and less invasive option. Smaller than other skylights, they capture light through a dome on the roof and channel it down through an internal reflective system.

The tubing used is flexible, similar to the material used for a dryer vent.

Because it is lined with reflective material, it is far more efficient in transmitting maximum light gain as opposed to a traditional drywall skylight shaft, which can absorb up to half the light on its way down.

Another advantage of this tubing is that it can be snaked between rafters and through trusses so it can be installed easily with no structural modification.

At the ceiling level, the diffuser resembles a recessed light fixture, which spreads the light evenly throughout the room, increasing the daylighting potential without the need for a larger skylight unit.

Because the rooftop dome has a small surface area, tubular skylights minimize heat loss in the winter and heat gain in summer.

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Almost everyone has heard a horror story regarding leaking skylights, and with good reason. After all, they are a hole in your roof!

It is essential that you select a well-designed unit from a reputable manufacturer and that you have a well-qualified contractor oversee the installation to make sure the flashing is installed to the highest standards.

If are thinking of adding skylights to your home, they can truly cheer up your space and trim down your energy bills, all the while making your family healthier, happier and more productive! See what a little sunshine can do.

Architects Ann Robinson and Annie V. Schwemmer are the cofounders of Renovation Design Group, renovationdesigngroup.com, an architectural firm specializing in home remodels. Comments and questions are always welcome at ask@renovationdesigngroup.