LED bulbs are very much on the agenda for the National Trust at the moment due to the significant energy saving they can provide, and with the larger properties containing many hundreds of bulbs the savings soon add up.
With this in mind I was interested to read an article in the New Scientist recently about how differing light colours can affect our mood and energy levels, and that there is still some way to go to produce the ideal LED bulb. The colour level of a standard bulb of any kind is fixed throughout the day, whereas natural light changes between dawn and dusk, and this is used by animals to regulate sleeping patterns. This means that in the evening, when natural light levels are preparing us for sleep, artificial light sources are telling us that it is still midday and overriding this natural effect. For the same reason it is advised not turn off TVs and computers before bedtime to allow the body to get ready for rest.
Here is the link to the article (needs subsrciption)
If you can’t view the link above, here is a similar article from GE: