Friday, June 26, 2009

Dark Days

The Other Solar

Daylighting Saving Time

Passive Solar 1You probably have a dark secret. No, not the one you begged your friends to take to their grave. It’s the one in your kitchen, or bathroom or hallway. It’s that spot that always seems to be dark, even with the lights on. The place where no natural sunlight can reach and the place you just wish you could go without the need of a flashlight. Unless your home was optimally designed to take advantage of natural light, odds are you have a few dim spots that could use some brightening.

Not too long ago, your only option would have been to cut a large hole in your roof and insert a skylight – literally a window to the sky. Unfortunately, the skylight probably had too many disadvantages to ever become a popular option. They tended to be leaky, they let in too much heat and after a couple of months there was a thin layer of crud blocking the view and you had to risk serious injury or death by climbing up on your roof to clean it. They have improved since those early days, but there’s still no good option to keeping them nice and clear other than a ladder and a squeegee. Nowadays we have a few more options for bringing in natural light and you don’t have to risk life or limb as most are relatively maintenance free.

Passive Solar 2

Obviously the best way to take advantage of the sun’s rays to light your home is with proper design, but for the vast majority the opportunity to design or even extensively remodel your own house doesn’t arise. Fortunately, for the rest of us, there’s light ducting. You’ve probably heard of it before, there are a lot of names for it: sun tunnels, light tubes, etc. The technology has been around for awhile, but commercial products are just now starting to gain some traction with the public. You may have even seen this type of lighting in a store and not realized what it was or what it was doing to your shopping habits. Studies have shown benefits to the bottom lines of retail operators and also to mental and physical health of those who work, learn and live with natural lighting.

Top Tips

Passive Solar 3Find the Best Fit. Most new technologies use some sort of ducting to go from your rooftop where the light is collected to the area you want to brighten up. Some products are better than others at transferring light over long distances, so do your homework on the right product for your situation. Some passive lighting fixtures have alternative sources of light installed in them so that at night you can still get usable light from the fixtures with a flip of a switch. Others will need to be supplemented with additional electric lighting.

Brighten Up a Dark Place. These types of daylighting systems work very well in areas that don’t have windows such as interior hallways, bathrooms and basements, but are also a good way to brighten up areas that don’t really capture enough light from existing windows.

A Bright Idea. Also, remember that this is natural sunlight being transferred inside so the lightmaybe a little too white or bright for some people’s tastes. Most manufacturers have diffusers that soften the light or allow you to control how much is coming in. It is best to check the products out in person if a nearby showroom offers demonstration models.

Keep Your Cool. Since the light from the sun is actually one of the coolest sources of light compared with electrical lighting, most of the daylighting systems mentioned here transfer very little heat and block out UV rays. So depending on how much electrical light you can replace with a daylighting system, you can actually reduce your cooling load during warm weather by reducing heat-emitting electric bulbs.


…to your health. According to a MIT study of natural daylighting and the effect on the body, researchers found that our bodies prefer natural sunlight to electrical light to keep circadian rhythms in balance. Sunlight has also been shown to improve productivity and a person’s feelings of well-being. This may explain why people at work are so grumpy in the morning. Considering that most people work under fluorescent lighting for about eight hours a day and are indoors the majority of the time not spent at work, bringing some sunlight in to your home might just improve your mood.

…to your wallet. Although the up-front costs of installing one of these systems may seem a little steep – anywhere from a few hundred to over a thousand dollars depending on the complexity, size and brand of the system – remember you’re getting free light from the point of installation on. The payoff period may be pretty long to be practical, but that’s not taking into consideration the health benefits that can be associated with natural light. A typical installation costs about $700 for a fixture that covers nearly 200 square feet. Factor in a 30% government rebate (on most models) and that brings the cost down to around $500. The California Public Utilities Commission estimates that daylighting can save between 23-32 cents per square foot per year. Given those numbers, you can roughly estimate that one of these will pay for itself in about 10 years.

…to the Earth. This is just one more way to reduce your carbon footprint by reducing electricity usage. If you estimate that it would take about five 11-watt compact fluorescent bulbs to light that same 200 square-foot space for 12 hours per day, you would be saving over 500 pounds of CO2 emissions per year with passive lighting. Over the 10-year payoff period, you would also be reducing your carbon footprint by more than 2 ½ tons of CO2.

Getting Started

Unless you’re really handy, you can check out our database to find a contractor in your area to install these systems. Most companies that you purchase from will also help with installation, but it still wouldn’t hurt to talk to someone who knows what’s involved.

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