View Full Version : Warming Effect of Lighting

09-25-2006, 11:27 PM
I am planning on starting a small hydroponic setup in my home so that I can produce a variety of non-fruiting produce (herbs, lettuce, etc) over the winter. My concern is that during the day when my wife and I are at work we do not heat the house (I brewed last winter and my yeast went dormant). I was actually quite relieved when I heard that HID lighting systems tend to heat up the space they are in, and so now I am curious how much heat they produce so that I can decide an appropriate location for my plants. I plan on running a 400 to 600 watt switchable ballast MH/HPS setup (want to be able to expand and switch to HPS if I decide to grow fruiting produce) to start with and I may either add another next winter after I get my greenhouse built in the spring.

I currently have two options for indoor growing space:

Option 1: 8x12x8 Basement Bathroom...average temp in the winter is probably 48-52 degrees tops. Plants would be in a sizable shower using either an aeroponic or ebb and flow system based out of one or two polyethylene totes. shower is glassed in, would probably add mylar to improve heat concentration and light concentration if necessary.

Option 2: 12x14x11 bathroom with an average winter temp of between 50 and 60. Probably couldn't use mylar as it is a functional bathroom, but the added heat from the light would be a nice creature comfort early in the morning.

Any thoughts? I haven't done too much research on the optimal temperature for the plants that I am growing, but I would guess that if my light can bump the ambient room temp up in either of these rooms by about 15 degrees, i should be all set.


09-29-2006, 11:19 AM

HID lighting typically adds about 3.5-4 btu's of heat per watt. So a 600w light will give about 2000-2400 btu's of heat.

Which ever location you choose to place your garden is fine, just keep in mind that you want about 50-60 watts per square foot for correctly lighting your garden eg - a 600w light will be ideal for a 3'x3' or a 3'x4' area.

12-28-2006, 01:29 PM
Please consider plants need "fresh" air . This should be considered when you plan on using the lighting for any heating offset .

A well ventilated small area , small enough to take advantage of the heat output , and maintain an optimum temperature , might be better suited than an afterthought corner grow where your morning bath comfort comes first .

Getting temperature equilibrium with good ventilation is more art than science .

01-16-2007, 07:55 AM
I suggest that you look at the reflectors with cooling duct connections. You can connect a fan and duct to this to bring the (otherwise largely wasted) heat down to the floor level of your growing area. You are going to need to exhaust humid air from the grow area (and probably to replinish CO2 levels). Sounds like you are a good candidate of a small grow room where you can better control the atmosphere and not loose your shower.