And roughly 35% of the heat put out by a 1khps is wasted. Bc its withdrawn from the grow area. Not all of it. But alot of it. How many people you know running 1khps isnt either extracting the heat bc its too much. Or cooling it with ac to get temps down. Which in turn is heat not used, and wasted electricity. Nobody runs a 1khps and the temp be right spot on. Without some type of either cooling or extraction. Which is essentially wasted. How can you say any heat extracted out to the atmosphere isnt unused heat and isnt wasted. That makes no sense. Or if you have to cool the ambient air temp with ac. The heated air you are cooling has already used electricity to produce it. And now your using more electricity to cool it. After it's already been heated up. Is wasting. Either way you look at it. That's the samething as saying I'll sell you this dollar for 1.50 you wasted 50 cents bc it's still only worth a dollar.
Edit: my point is led will outgrow hps. Plain n simple. It takes less energy to produce the same results or better.
Hello-hello! I'm not saying hps is better, I would never do that!! I suggest you read it again!
I say, heat is not just wasted energy!
HPS produces too much of it but with 1000w in a 5x5' tent you only need a 6-8" exaust to maintain the temperature at 25-26°C. AC only in midsummer but that's not what I wanted to say.
What I wanted to say is, heat is needed for the plant to grow and at only 15°C and 1500μmol/s you will not get good growth. A certain amount of heat is still needed also with LED.
HPS produce much of it and produce it directly. LED's have a cold light without the 25% infra-red of hps and the heat inside a tent is created by reflection/conversion cause light gets converted into heat when it hits a surface. For this reason also LED light feels warm even if its not so warm like HPS or sun light.
The whole calmag issues is because of the missing infra-red radiation because plants use heat radiation to regulate certain processes like transpiration. Plants in sun light can withstand 2000μMol/s and +40°C without getting damaged because they would simply reduce transpiration and close the stomata. Far/infra--red has also signalling effects and without a certain amount of heat plants would get issues.
For this reason we have to increase ambient temps with LED to get the leaf temps in the desired range so the plant can regulate the processes successfully. But higher ambient temps cause a high VPD and a higher humidity is needed to get no nutrient imbalance.
When you grow on an open space with no reflective walls its much more difficult to get the desired 28-30°C ambient temps with LED. In a siutable tent much more light gets reflected and therefor its easier to maintain the desired temps.
I know some who for example still use HPS in the coldest winter month because their basement or garages simply stays too cold for LED's.
I've no interest teasing you, bro! I only say, plants need light AND heat to really grow fast.