to insulate or not to insulate
I have a question, which will require a guesstimate from someone who knows the impact of insulating, specifically in the roof, above the ceiling.
We live in Markham, just north of Toronto, and are considering blowing insulation into the roof area of our 1700 square foot brick bungalow. We have done all the other walls in the house, and are considering doing this, when the kitchen is being renovated. However, it's going to cost us and additional $1,700 for this job, and we're not really sure if it will be economically feasible. This is an old house (double bricked) built in the late 60's when heating costs were not a majour concern. The contractor says that it is currently about R10, and that inslulating it would increase it to R50. Is there anyone out there who can give me some sort of guesstimate as to how much we might save on our heating bill (%wise), assuming cold winters. We will likely be in the house for the next 20 years, assuming we live that long.
Thanks for your help. I know this is a tricky question, but I'm really not sure if we should spend the money or not.