Good old HPS is good old HPS, but if you dont grow outside, why does it matter much if its summer or winter? I mean if you grow inside of your house, do you keep all the windows open in your grow room in the winter or what? I know some might be able to pull out air from outside or they grow in some cold garage, but i think most people with tents grow inside. My indoor temps are almost the same, it doesent matter if its -25C or +25C. Sure i could open all my windows in my apartment and make it really cold inside, but who would like to live that way? xD Sure if its an extra hot day in the summer, the tent temperatures might go up 2 or 3 degrees(using HPS), so LED would be better in some extra hot days. But the heat from HPS does nothing more than dry up the air in my flowering tent really, which means good humidity in the summer and waaaaay too low humidity in the winter without using a humifier. On my veg tent i have a LED and that doesent dry up the tent as much, so its good for that. Especially since i dont have as strong air removal from it, it keeps the warmth and moisture in there well.
im not against HPS and use one myself, im just pointing out that the heat from HPS does not help most people winter, unless you try to grow in some cold spaces like garage or put your tent outside in the snow.