I helped install the LED light for our neighbour earlier this year, and it was pretty simple and reasonably energy efficient, although it drew around 120 watts when running at full power. It didn't have a fan, but the LEDs (hundreds of them) were bonded to a large finned heat sink. The neat thing about it was that it had a variable light adjustment, via a knob attached to the control box. I set it up for her on a time switch, so it came on early in the morning and turned off around mid-morning, to fool the seedlings into thinking the days were longer than they really were.Mr Gus wrote: ↑Mon Oct 31, 2022 11:22 am We have so many flights going over us & police / air ambulance that i've been really wary to use a decent sized led array, the idea of bust doors & search warrants for non existent drugs would probably cost the life of at least one dog if they decided to turn up.
would try first with a singular led 60 - 100 grow bulb which is what used a few years back for spot growth on a heated seedling tray. ..even the leds will cost you a lot (usually have fans built in for overhead set ups)in terms of running costs.
Seemed to work OK for tomatoes and it didn't give off a great deal of heat. Interesting design, though, as there was a mix of LED colours, mostly white, but interspersed with some red LEDs and some that looked a sort of violet/blue colour. Presumably this was optimised for the wavelengths that leaves absorb energy. I'll try and pop around to see her later and ask if I can take a photo of the light.
In her case the greenhouse is a sort of lean-to conservatory built along the rear wall of her house, with her back door opening directly into it, so the waste heat was perhaps being partially recovered by the reduced heat loss from that wall. Very obvious when the light was on, though. Her house is about 80m or so from ours and the glow from the light when it was on was very obvious when we looked out of our spare room window early in the morning. I don't believe it attracted any attention, though, even from the DCI that lives in the house behind ours and has a clearer view of her place then we do.