Lighting Heat

Lighting Heat
9 November 2004

Dear Scott

I love your web site, very informative, and you always seem to be quoting from research, tests, or experiments, unlike other jerks who ram their unsubstantiated opinions down your throat like it’s fact. WELL DONE!!
Aww shucks. Now I’m going red…

Thank some of my scientifically minded customers who help me with testing these things out.

I have scanned your web site and although you talk about heat from lighting etc, I cannot find a direct reference to my questions so here goes:

Taking into consideration the heat from the globes only as the ballasts are in the roof, what will run cooler in my grow space 2 x 400 watt son-t-agro or 1 x 1000 watt lucagrow? My curtained off grow space is approximately 1.4m x 1.4m within a small bedroom approximately 2.4m x 3.0m.

800Watts (2 areas of 1mx1m) will be less hot than 1000W (1area of 1.7×1.7) and thus more efficient in distributing light. 1000W can penetrate plants ideally no more than 1.7m high, and 400W ideally no more than 1m high. (not exact figures – depends on reflection, density of plants, etc) 2x400W will not increase the height available to you. You can always tie down plants that are too high.

Also: what type of shade helps keep the heat to a minimum

A Starwing/Ultra style or a china hat ( 400 watt). (see also Cool tubes which suck air off the lamp before the heat can influence the growroom)

The Starwing will allow more heat to spill out the sides, and the smaller the reflector, the less heat can be trapped under it.

Chinahats have only a small area near the top to ventilate. Consider fan ducting (150mm diameter) attached to either reflector and stretch ducting until next to the exhaust fan and you should have some suction of heat directly off the bulb.

Is a son-t-agro more efficient burning vertical or horizontal?

The burning position is optional. A lamp which is long and thin, will tend to send more light perpendicular (90deg) to its length. So I suggest horizontal would be brighter.

I also have a 600 watt that I purchased from you ages ago but when I put it in the room with the 1000 watt the heat sky-rocketed.

1600Watts can be fairly warm. Since a percentage of energy produced is light, and some is lost in heat, a proportion more lighting should result in proportionally more heat according to its efficiency. GE lamps ran cooler than Phillips in one test we did. Some of the latest lighting has been overpowered for results and I suspect their efficiency is not what is in the figures when run with a real world ballast. e.g. run 1050-1100Watts into a 1000W no-name globe, and the manufacturer find they have the same or better output than the standard GE or Phillips. So the manufacturer publishes the figures with 50-100W more light going through the globe and do not care about the longevity of the lamp when overrun. Then sell it, and the output is fairly average in a 1000W ballast, maybe 10% less. The same power applied must go somewhere, so the loss might be in heat. The heat lost from the poor design will add to the low light output = double problems for your growing room. How efficient a lamp in converting available power into light can indicate how much heat loss is generated but not always. (i.e. good light may mean low heat but only if tested in the same ballast.)

Not sure where that lighting info comes into it – but the more you know, the better I guess.

I have 1 x 1000 watt adjusta-shade, 1 x 600 watt china hat, and 1 x 400 watt china hat. I want the coolest combination, and don’t mind purchasing whatever it is I need to achieve that.

Would very much appreciate your thoughts.

Thank you for your time.

The issue could be given the area you wish to light up (1.4mx1.4m) would be best witha 600W (1.5×1.5m max). Considering maximum results you might do better with an area 1mx1m for 2x400W.