I heat my shop with gas, and before I got the laser my gas consumption was about 700-750 cm, after the laser went in, my gas consumption is about 800-875 cm. So, the main floor of my shop is 832 sq. ft. the second floor is heated by the heat rising from the first floor and is about 650 sq. ft
so with that floor space, I only seem to use about 125 cubic metres a year more.. At night and weekends the shop is 56 deg F. and only 68 deg Mon. to Fri. My current gas cost is 12 cents a metre so my increased cost is minimal. I may be in Canada, but my latitude is further south than many of you in the U.S.