IF you are running your lights just to keep the temps from crashing in a cab. th
In a 60h x 30w x 48l cabinet I have used a submersible 50w aquarium heater kept in a 1 gallon glass jar of water to keep my temps plenty warm.
you can also run 10/2 + 10/2 in veg and flower for autos
or 6/1 +6/1 +6/1 + 6/1 in flower for autos.
This will give you the light hours you are looking for without the heat loss of 4 continuous hours of dark.
I have used these schedules with autos without any obvious problems, however I prefer 24/0 as it suits my lifestyle and habits and I am reasonably pleased with my results.