Painting the walls a dark color, or not painting the walls at all. A key factor in the brightness of any space is the reflectances of the surfaces. The more reflective your walls, ceiling, floor, and furnishings, the less it will cost to make the room feel bright. A can of white paint is one of the most inexpensive lighting accessories you can buy.

Closing shades or draperies to keep out daylight. (Or letting the daylight in but leaving the lights on anyway.) Daylight is free, has all of the characteristics people crave in lighting - good color rendering, changing throughout the day to improve circadian rhythms, and did I mention free? Adjust the blinds to direct glare toward the ceiling, but keep the light switch off when the sun is shining.

Not using dimmers. At certain times of day or on certain days of the year people need or want more light. At other times, less is better. Dimmers save energy and increase lighting satisfaction by giving occupants control of their spaces. They're easy to install. Do it. You'll be glad you did.

Forgetting to take advantage of warranties. Sure, we've all had bad experiences with either an LED or CFL lamp. But do your research to find a high quality product from a reputable manufacturer that meets your lighting specifications. Then hold them to their warranty. If something goes wrong, don't go elsewhere. Go back to the manufacturer and get them to fulfill their warranty. That will help them improve the products in the long run, too.

Avoiding new technology. New technology does require you to understand more about lighting and the visible spectrum. You have to watch for the right color temperature and good color rendering. Lighting quality issues aren't simple. But if you choose carefully, the energy savings will be worth the extra front-end effort.

Which lighting mistakes are you making? Which is most surprising to you?

There are three viable major categories of incandescent lamp replacements available today. Think of it like an election. 
Consider all of the options and then make your selection - cast your vote. Sometimes, like in an election, you may have to pick the best of the worst...but you do have a choice, so your duty is to become informed about those options before making your selection.

This lamp type is most similar to incandescent in cost, color, physical appearance, light, dimming behavior, 
technology...in nearly every way. Halogen is about 30% more efficient than standard incandescent and lasts about 
twice as long. The advantages and disadvantages almost perfectly align with advantages and disadvantages of incandescent lamps. They provide instant-on light. They are fully dimmable, The color rendering (CRI) is 100. With 
incandescent or halogen, there are no color temperature options They do not require a ballast. They are mercury free, 
TCLP and RoHS compliant. They are not sensitive to ambient temperature. They tend to be sensitive to vibration.. 
They produce heat when they operate. An A-lamp replacement will cost under $2 and will pay you back $3.08 in energy savings over its lifetime.

This lamp type is the one consumers are being told to use instead of incandescent. CFL is about 75% more efficient 
than incandescent and lasts about ten times as long. Their function is actually quite different than incandescent, but 
they have been fairly common for fifteen years now, so people have grown accustomed to their strengths and weaknesses. They aren’t exactly “instant-on”, but require a brief warm-up, so they are not the best option for very transient spaces or spaces controlled by occupancy sensors. They can be partially dimmable with the proper ballast, The color rendering (CRI) can be low - and that is one reason the CFL has gotten a bad reputation, but look for a CFL lamp with a CRI in the mid-80s for satisfactory color rendering. 
Often I hear people say, “I just hate the color of fluorescent light.” Fortunately, fluorescent is available in a variety of colors. Be aware of that and be sure to get a color that you DO like. Once upon a time, lamps available in big box stores did not display the information needed to select the color. But now that is changing. Starting in 2011, the Federal Trade 
Commission began requiring lamp packaging to bear a label like this:

Notice the section called "Light Appearance" which indicates how warm or cool the light looks. The warm colors more closely resemble incandescent.

This will be an even more useful tool when CRI is included, shown as “Color Accuracy” in the above DOE Lighting Facts label for LED. CFL lamps do require a ballast. They are not mercury free, but the small amount of mercury used in a high quality lamp can make it TCLP and RoHS compliant. They are sensitive to ambient temperature, and don’t operate as well in cold weather. However, there are lamp ballast combinations available that work well in temperatures down to -10 degrees F. Compared to incandescents, they are not particularly sensitive to vibration. However, if used in an application where they are turned on and off frequently (less than 3 hours per start) the lamp life will be significantly shortened. A 100W A-lamp replacement will cost about $5 and will pay you back about $50 - $100 in energy savings over its lifetime!

While this replacement option is generally being written off by consumers as too expensive, it is an incredibly hot 
item in the specification market. LED is currently about 85% more efficient than incandescent (and its efficacy is still 
improving because the technology is still young) and lasts about fifty times as long. Unlike fluorescents, they do provide instant-on light. They can be partially dimmable, typically down to 10% with the proper equipment coordination, The color rendering (CRI) is often similar to fluorescent - but look for a CFL lamp with a CRI over 90 for very good color rendering. LED lamps require a driver, which is similar to a ballast. They are mercury free, and unlike all of the other lamps, they are virtually UV and IR free, so they will not fade fabrics or art. They are sensitive to high temperatures, but they love cold weather. Heat is their enemy, and the astute designer will look for good heat-sinking to ensure that LED junction temperature is maintained at its ideal level. They are not particularly sensitive to vibration. Some look yellow when they are not in use. Others are available in a more traditional looking white color. An A-lamp replacement will cost about $25 - $40 and will pay you back about $240 in energy savings over its lifetime!

This is an exciting time in the lighting industry, with the pace of change increasing exponentially! How can you possibly keep up with it all? My recommendation is to hire a lighting designer. It is my job to keep up with all of these changes, and it has been my privilege to share them with you! I believe that the importance of having a lighting designer on your projects will continue to increase as the technology changes, because lighting designers dedicate themselves to the art and technology of light, and can help you avoid the pitfalls of selecting the wrong technology or even the wrong version of the right technology.

Color is so much stranger than it seems at first glance. When we were children learning red, green, yellow, orange, blue...it seemed so straightforward. So easy to get the right answer. When did you realize that it was all a sham? An illusion? For me it happened in high school when I always wore socks to match my shirt (yea 80's!) I bought a pair of royal blue socks - perfect - until I got them home under the incandescent light. They were purple. What? Okay, then, fine. I'll wear them with my purple shirt - until - I got to school and they were blue again. How mortifying. What had happened?

In the previous post we looked at the color temperature, or color of the light. That actually has little to do with color rendering, which is the color of the objects under the light. See the difference? Either a warm source like incandescent or a cool source like daylight can render the color of objects nearly perfectly (my socks were blue under both.) It has to do with how much of the pigment is reflected back to your eye by the light source.

The three pictures above subtly illustrate differences in color rendering (or color accuracy) on the apple. The apple is the same, but it appears more pink, orange, or deep red under different lights. In the picture on the right the yellows in the apple are easier to see; In the middle picture, the dark lowlights are well defined; The one on the left seems smooth in color - neither the lowlights nor the yellows are obvious. It is important to know not only whether a source is warm or cool (color temperature) but also how it renders the objects under its light (color rendering.)

The new Lighting Facts Label (at left) required on light bulbs (lamps) sold in the US lists the color of the light, but not its color accuracy. Another new label (below) uses both. As a consumer of today's complex lighting sources, you need to know both. The color accuracy scale goes to 100. In most cases, choose the highest number you can afford. Something in the 80s for fluorescent and close to 90 for LED. If you have the opportunity to try multiple sources to see how they look in your final application, that is even better. Check color accuracy to avoid disappointment and purple...no, blue...no, purple socks - or worse!