Bad habits never die

In these times of looking for the best lighting efficiency, “changing the bulb” for a low energy one is the predominant response to the issue. Additionally the idea that a “small” low energy bulb affects only marginally our general electricity consumption remain well rooted in the common mind.

The light reflected by the surfaces and that emitted by light sources interact to produce the spectrum that is perceived by our eye. Since colors and surfaces significantly affect the lighting of a space, good lighting can not be designed without considering the characteristics of the environment itself and especially the colors present in it.
Obviously individual taste in terms of decoration, such as wall colors and furniture, must be taken in consideration. But only as much as they do not end up multiplying “small” low energy bulbs, as, in the end, all these low energy light bulbs, plus some halogen in the hall, plus a pair of table lamps and a few spots, are capable of burning one third of our electricity bill at some times of the year.

Getting back to walls color, the first thing to understand is that the white is always the brightest color, or in other terms, that white is without exception always able to amplify the brightness of a space under natural or artificial lighting. Any other color subtracts a portion of the light that the walls are able to reflect and redeem to the surrounding. The idea, for example, that a yellow hue may increase the power of light’s reflection is utterly wrong. In reality, the luminance of a colored wall is always lower than the one of a white wall.

Furniture also impacts the brightness of a space. Not because of its color, but rather because of the quantity of furniture. How often do we see clutters of cabinets, ornaments, pictures, maps, tables, chairs and more darkening entire living spaces? Before you start filling every inch of white wall or every inch of floor you better consider how much this will cost you in terms of energy. And not only for lighting, but also for vacuum cleaning...

The proper rule is to use the light as a guide for the perceptual process, leveraging its ability to “underline” the space. The light becomes the channel between the object and its shape, adjusting the contours and dramatizing the space limits.

Comparing apples to apples, at last...

In the vast background noise written on the subject of LED vs other light sources comparison, this post is a little gem. James Alexander makes an excellent job at summarizing the issue with easy to understand day to day examples. Moreover, the cited numbers are among the most up-to-date at this point in time.

Although I disagree with him on the subjective matter of using 5 mm LEDs as a "real ligh" source, this is definitively worth reading.