Sorry I know this has probably been answered and I've used the magic answer box but my lil brain can't figure this out. I use a 300 watt and a 400 watt cob fixtures. I run them full power to flower. One has adimmer one has a veg/flower switch. MySpace is 32" wide and 9 ' long. My space is too hot now by about 5° -10 degrees even with a/c and it's sealed for co2. would comparable qbs make a difference heat wise? Thanks a lot. I don't quite understand efficiency as it relates to heat.
Your air will only get as hot as the hottest tech. If your light operates at 88F, your air won't ever be 89F. The air needs energy to heat up, so the max temp it can ever be is possibly the temp of the hottest thing in the room.
1W in a box is 1 joule of energy added every second to a box, it's a rate. Air is only a fraction of the mass in the box that absorbs this energy. "Ambient temperature" is ONLY referring to the "air temp," so how much of that energy is absorbed by the air is what's important when talking about how much "heat" a light creates.
If your COBs are hot, then your air can also have the possibility of being hot. If you run the COB wattage but through QB's, or more COBs, your operating temps won't get as high and your temp should come down. Then it'll be a matter of the heat capacity of your room and how thermally conductive it is that will decide the rate of temp increase per watt of EM, or visible light (neglecting your AC).
Imagine a 5gal bucket with a hole in the bottom. As soon as you start to fill that bucket with water, a little bit will start to leak out the hole. Initially your rate of water going in is greater than the rate of water going out the hole, so the bucket fills up slowly. But then it gets to an equilibrium point where the rate of water going in equals the rate of water going out. If you added more holes, the water would drain faster and your equilibrium water level would drop, conversely if your filling flowrate increased the equilibrium water level would rise. The equilibrium water level is the air temp. How many holes are in the bottom of the bucket, is like how well your room transfers the EM energy it absorbed away. The size of the bucket is like the heat capacity of your room, the more mass it has the more energy it can hold without increasing its temperature, or how much water you can add before the water level rises an inch (or air temp raises 1°), like the difference between a 5gal bucket and a kiddie pool. If you've only 1 hole, your container is small, and you're pouring water in fast, or running lots of wattage, then your water level is going to rise quickly and your final equilibrium water level will be quite high before equilibrium is met. If your container is large but has only 1 hole, and the flow rate is normal, then it will take quite sometime for the water level to rise, the hole may offset the filling flow rate to the point that you don't see hardly any temp increase, and then the 12hrs of time with lights off, or the filling hose shut off, the drainage hole has been able to drain any buildup it had accumulated throughout the day. You could have a small container, high flow rate, but a high amount of holes and not notice much water level rise. Also, if the outside air or adjacent room is warm, it'll have an effect like reducing the number holes in the bottom of the bucket. Heat travels from hot to cold, so if it's hotter outside, then your room will have to be just a hair hotter before it will begin to conduct any energy away.
You can see now that there's a few factors involved when it comes to ambient temp increase and lighting. Some people may have huge increases to ambient, while some may not even notice it. The thermal conductivity of a wall or barrier, the outside temp, the mass of the wall/barrier all contribute to how a room will transfer energy, but your air temp will never be hotter than the hottest thing in the room. Keep the hottest things cool, and your air temp will also be cool.
Also maybe sealed is your gal, but I think exhausting old and bringing in fresh is a good way of maintaining CO2, also a bit cheaper to remove heat that way, but just my opinion, I don't use CO2 so I can't really give a legitament comment on growth comparison with or without.
