Daylighting means using the sun as your main light source during the day. You may be able to increase the amount of free light you get from the sun by making a few basic changes. Start by looking at your furniture arrangement: Could you move a desk or reading chair closer to a window?
Daylighting offers too many benefits to pass up:
- Sunlight is free.
- Daylighting decreases your dependence on the power grid.
- When you use less electrical lighting, you lower your contribution to greenhouse gas buildup.
- Sunlight is dynamic, constantly changing in direction, intensity, color, and warmth.
- Sunlight makes you feel good. It links your internal clock to the sun’s cycles. Regular, prudent exposure to sunlight may even improve your health and mood.
Because the sun follows a predictable path, you can plan your daylighting based on your family’s schedule. You might turn a dark corner of your kitchen into a cozy breakfast nook that catches the morning sun, or put a window in a solid door to light up a dark foyer.
Pay attention to where the sun shines into your house, and how that shifts throughout the day and the year. Are some rooms too dark, and others too bright? Make notes on how you’d like to change the daylighting in each room.
Now explore ways to add, remove, block, or treat windows to let in more sunlight where you want it. If you live in a hot climate, you’ll be glad to know that you can choose windows or apply special treatments to keep out the sun’s heat while letting in its light.
Look around the outside of your house. Are your landscape plantings supporting your daylighting schemes? Trimming, adding, or removing vegetation can significantly change the daylighting in a room. Roof overhangs, shade trees, plants, and the ground surface outside your home also affect how light comes through your windows.
If you’re planning an addition, you have the opportunity to design for daylighting from the start. Be sure to also take into account how the addition will change the way sunlight falls into existing rooms.
Plan Your Daylighting
To best use daylight, think about how each room will be used:
- Is it a space for paying bills or reading? Place desks and reading chairs near windows, but facing away from them if glare is a problem.
- Will people gather there? If sunlight will shine directly into people’s faces, install blinds that direct light toward the ceiling, hang curtains to diffuse the light, or simply rearrange the seating.
- Does your family watch TV, play video games, or use computers there? Position fixed screens so they don’t reflect a window (or an electric light), and consider where people will sit to use portable items. Test the reflection by holding a mirror where the TV or monitor will be situated. If you see a window or a light in the mirror, there will be a reflection on the screen.
Designing Windows for Light
Windows are the key to sunlit rooms. Here are some helpful rules of thumb for designing and using windows to admit light:
- An unobstructed glass area equal to 5% of a room’s floor area should provide adequate ambient light.
- Windows on more than one wall make a room feel lighter and more dynamic.
- The higher the window, the farther sunlight can reach into the room.
- Clerestory windows (a series of windows high in a tall wall) can light spaces directly, or indirectly by reflecting sunlight off walls and ceiling.
- Unobstructed north windows provide relatively glare-free lighting.
- Borrowed light makes use of glazed interior openings to transmit light from a sunny room to a darker room or hallway. To maintain privacy, use textured glass or glass block.
Sunlight from above makes a space feel open and lively while reducing the need for electric lighting. Skylights needn’t be large; a skylight can illuminate a room twenty times its size.
Tubular skylights have a highly reflective inner surface that bounces sunlight into the living space. A tubular skylight can be a good choice for a small, dark space, such as an interior hallway or a windowless bathroom.
If you choose a conventional skylight, you can distribute sunlight more broadly into the room by angling the walls of the light well through the attic. For either type of skylight, make sure the light well or tube penetration is insulated where it passes through the attic, and that it is well sealed against air and moisture from the attic and outside.
Balancing Daylight and Solar Heat
Too much sunlight may make your house too warm. Here are some ways to avoid this problem:
- Install rollup shades inside or outside the window; exterior retractable shading blocks solar heat more effectively than interior.
- At south-facing windows, add an awning or overhang to block direct sunlight.
- Apply reflective film to windowpanes.
- If your winter heating costs are low and your summer cooling costs are high, choose window glass with a low solar heat gain coefficient.
- Plant deciduous bushes and trees outside east- and west-facing windows—or train a vine up a vertical trellis—to filter hot summer sunlight and admit winter sunlight.
Daylighting on a Budget
If the daylighting in your home isn’t ideal—and your budget doesn’t include new windows—try some of these low-cost tricks:
- Light-colored walls and floors bounce light around a room and make the space feel bigger and brighter.
- Semisheer curtains or glare-reducing window treatments diffuse intense sunlight.
- Blinds or plantation shutters let you control how much light gets in. For large, wide windows where horizontal blinds would be heavy and difficult to manipulate, try vertical blinds.
- Light surfaces outside your windows (such as a light-colored patio or path) will reflect sunlight into a room, while vegetation or dark surfaces will absorb light.