controlling the temp of the actual room rather than the tent
Luxury... I'm banished to the loft, battling the temps on my first 2 grows was fun but I've got it sorted now...that tent is the warmest place in the house now.
A 80w (3ft) tube heater will give you about 5-10c over all. Should do you proud as your heating your room, £20-£30 on amazon. I have mine on all the time.
I recommend getting a thermostat controller like mine, sorts it all out, no need to keep checking.