Bio-dynamic Lighting Revisited
Last week I mentioned that on Grand Designs Series 19 Episode 3 the subject of bio-dynamic lighting had come up. The impression was given that the clients had ended up with this but I don’t believe that’s what they got.
First I think I’d better explain what bio-dynamic lighting is. We will start with an understanding of how natural light behaves. The colour temperature of natural light changes throughout the day. It starts with cold (blue) toned light in the mornings, moves towards warm (yellow) toned light in early afternoon towards very warm (orange) toned light later in the afternoon into evening before it gets dark. The colour temperature of light is measured in kelvins with the international notation being K. Our daylight typically starts at around 6500K and warms through to around 2700K. Therefore, bio-dynamic lighting needs to be able to at least cover the spectrum from 6500K to 2700K. This cycle is repeated daily and the proportions of blue, yellow and orange light. The proportion of light or darkness obviously varies throughout the seasons.
We evolved to live in natural daylight. How wakeful or sleepy we feel is controlled by hormones that are affected by the light levels around us. Our general well-being is now known also to be affected by amount and length of daylight in our days. Bio-dynamic lighting is artificial (electrically powered) lighting that has been designed to automatically behave like natural light. The people working or living within spaces lit by it feel like they are in or close to natural daylight. Examples of places that use bio-dynamic lighting are:
- Work places with a shift system – the bio-dynamic lighting is run for each shift. Te workers feel like they are working during standard offices hours even if they are working over night. This can help their general well-being and also improves the level of alertness that usually diminishes at night.
- Internal rooms in hospitals, care homes, schools and businesses with no or very little available natural daylight.
- Other rooms where regulating the user’s body clocks (AKA circadian rhythms) working naturally help their health and well-being. Hospitals and care homes particularly benefit from it.
The cycle of changing the colour temperature of the light needs to be carefully controlled. These subtle changes can only be sensibly done by a lighting control system with a built-in time clock. The intelligent time clock also tunes the colour temperature of the lights based on its longitude and latitude. There is a lot of technology involved in bio-dynamic lighting…
My first alarm bell about it being bio-dynamic lighting was that I didn’t believe that the downlights they used covered the required colour temperature range. I recognised the products and they came from the downlight supplier that I specify most frequently. I called them to check in case something new had come out that I hadn’t been told about! Their reply was that it was their product. I checked their spec sheet and the colour temperatures they can create ranges from 2650K to 1800K. This is far too tight a range to be considered as bio-dynamic. The second alarm bell was seeing them walk over to a standard rotary wall dimmer switch and turning the knob to change the colour temperature. Where were their lighting controls set up to emulate the natural cycle of colour temperature?
I do not believe that they have bio-dynamic lighting. It seems that they got LEDs that emulate the way that older incandescent and halogen lamps behave. It is something that all of us who had dimmers in the past took for granted but it is something that most LED lights still aren’t able to do. The colour temperature of the light produced by these LED downlights gets warmer as they dim – the same as it used to with older lighting technologies. This is commonly known these days as dim to warm or warm-dim.
On the plus side I have been able to peel my potential client off the ceiling. I had told her that the bio-dynamic downlights that I know are suitable for domestic use were around £300.00 each and that she would need a lighting control system. If she just wants what she saw on the tele then she can get the downlights for under a third of that original price and she can have normal LED rotary wall dimmers that are also a fraction of the cost.
If you or anyone you know are looking for bio-dynamic lighting or just LED dim to warm lighting or you just want your lighting designed with a transparent approach please contact me.