U.S. Department of Energy - Energy Efficiency and Renewable Energy
Energy 101: Daylighting (Text Version)
Below is the text version for the Energy 101: Daylighting video.
The video opens with "Energy 101: Daylighting." This is followed by various shots of building interiors with many windows and large amounts of natural lighting.
Okay, so we all know that windows can provide a great view, right? But if they're placed in the right locations, they can also save you money on your utility bill…and they can help keep you more comfortable at home or work.
A montage of building interiors and exteriors appears onscreen, with windows filling the interior spaces with natural light.
It's called daylighting, and it takes a simple concept to a new level. Daylighting combines lots of things—everything from the type of window, window placement, and interior design to control how sunlight comes in. They all work to maximize benefits from natural sunlight.
An animation of a building appears onscreen. The building is covered in large windows, and the front side of the building is labeled "SOUTH" for the direction it faces. The building rotates to show the north, east, and west sides of the building as the sun moves from east to west overhead.
Check this out: windows that face south are best in the U.S. They let in the most light in the winter months, but little direct sun during the summer, keeping the inside cooler.
North-facing windows are also good for daylighting. They let in even, natural light with little glare and little summer heat.
Windows that face east and west don't work nearly as well for daylighting. They provide lots of light in the morning and afternoon, but it often comes with lots of glare and excess heat during the summer months.
The video shows exterior and interior footage of an energy efficient office building with a large amount of daylighting.
Have a look at this energy efficient office building. The windows team up with skylights to provide most of the light you need.
The video moves to shots of the ceiling and overhead lights.
Notice the light color of the ceiling; it reflects and enhances the daylight so that it fills the room. And what about all the overhead lights? Most of the time, you don't need them!
The video shows exterior footage of the office building's windows, then shows the windows from the inside the building.
To account for glare, this office building placed hoods outside, around the windows. The hoods also cut down on summer heat, keeping the office cooler and more comfortable. On the inside, louvers or tinting reduce glare and also direct light to reflective surfaces inside, allowing plenty of natural light to come in to work areas.
Various shots of the building's windows appear onscreen.
One big help to daylighting is the window technologies available today. Windows are now way more energy efficient—they insulate while still letting the light you want in.
The video shows timelapse footage of an electrochomic window darkening as more sunlight shines through the window.
And have a look at this: it's an electrochromic window. This special window changes with the brightness of the sunlight outside. As the sun tracks across the sky, it darkens to keep excess heat out. It's like giant polarized sunglasses.
The video shows footage of people working in the daylit office building.
Daylighting can have a positive effect. Studies have shown that with good daylighting at the office, productivity goes up and absenteeism goes down. And that's good for the bottom line.
The video shows various shots of building interiors with many windows and large amounts of natural lighting.
Natural lighting and heating means you use less electricity—and lower your utility bill. And the more natural lighting, the more money you can save.