mh utility cost 2x4 vs. 2x6 construction

[dannyell]

I am wondering if there is a significant difference in cost between the two construction methods. I currently live in a 72 pre-hud singlewide made from 1x3s have gas appliances furnace etc. My utilities run 250 a month. I live in Minnesota also. So I am looking into purchasing a double wide about double the size. Will this cost me more to heat or can I asume it will be close to what I pay now with my under insulated home. With the mortgage I would like to have it payed off in 7 years verses 20 but if my utilities double that would be impossible with the rise in insurance taxes etc. I am just looking to set a reasonable budget. Nobody seems to mention what they pay for utilities. In my research i came across an article study idk that said the uprgrade from 2x4 to 2x6 would take 78 years to break even! And a saving of $30 month. Is it even worth it? I have done some research and read most all of the posts on this forum so far with no answer so any help would be greatly appreciated. Thank you in advance.