VPD is determined by leaf temp, not root temp. Using a heater seems like a waste of energy to heat up the leaf temp. I figure it's better to use some HID type lighting to get the infrared heat blasting directly on the leafs, and you also get the nice side effect of photons. In winter, I will struggle to get temps above 70 with LED lighting only and no supplemental heat. Part of the issue is that I have to run lights at night when it's cooler, because the cost of running them during the day is like 4X vs at night.I read a lot of post which say this, and it makes me question if people are doing the right thing using the light to heat their environments and not floor heating to warm up the roots.
What are your temps in the winter season and what changes do you make from summer to deal with it?