Just out of interest, How much was your gas bill for the last month? Mine was 100,000 won and it hasn't really become too cold yet. I live in the country and our gas gets delivered and I'm wondering if the extra 100,0000 won we get for rural living is really enough. Please tell me how much your gas bill was and whether you live rurally or in a city.
Most buildings I have been in here are poorly insulated. You lose a lot of heat through the windows, doors, and walls. I would not recommend trying to keep your room at a constant temperature. Just turn the heater on when you're home and when you need it.