Quote Originally Posted by keith3267 View Post
You are right that additional insulation reaches the point of diminishing returns very quickly, but the codes are not made on return on investment calculations, they are for the most part political. You can make a case though that there is an unseen ROI. If no one increased their insulation, then there would be more demand for energy and the cost of energy would go way up. Because so many people increase their insulation and furnace efficiencies, the cost of energy is lower and that reduces the visible ROI.
Lol ! I wouldn't say the required insulation value is political. Try living in a place with cold winters and see if you think the same thing.
The minimum required R value is based on a return on investment; for comfort and reduction related to HVAC operating cost and size. Exceeding the minimum amount of insulation isn't necessarily a bad thing if you can bring the heat loss or gain down to the theoretical zero mark. In most cases the cost of insulation isn't all that expensive and as one regular here , Canuk , says it doesn't cost a dime to operate or maintain.
The cost of energy isn't going down.