arty, what's your very mellow temp cycle? Even in my window grow I have a pretty good day/swing, could be -30 on the other side of the glass in early spring, lol, why am I laughing?
Hi Trail
I used to run 520W of led, which was a bit over kill.
All three light had fans and so the warm air circulated nicely I also had insulated wall in my cab.
The temps stayed pretty constant and my extraction fan is dual speed with a thermostat, so 25C pretty much most of the time.
I now have the Northern Grow lights DIY LED COB light, passive heat sinks (so no additional air circulation from the light).
It draws 300W and is most probablly more efficient than my old LEDs so, I am using 220W less and the COBs are more efficient, which means a lot less heat being produced.
I have better insulation now though, so that will help keep the temps stable.
My temps don't vary much maybe 3-4C so 21C - 25C which is more of a swing than with my old lights, where it remained around 25C most of the time.
When the summer comes this cooler light will come into it's own, when things get a bit hot out side.
When the temps go above 25C outside than i'll notice inside getting a bit warmer but the temp controlled fan can help with this but if the temps rise too much then no choice to have a dark period in the hottest part of the day in the afternoon to the early evening.
As a rule I like to have a bit of time of from growing in the summer so I don't have to worry about getting home to tend my plants.