I am 54yrs old and have only 3 yrs left on mortgage.. I want to put on a new addition to house and looks like I will have to borrow $80,000.. Do I want to do home equity or remortgage? I would like to retire in 11 yrs or less

That's totally up to you. It might be better to have a home equity credit line for the future. But either way is valid.

The best thing is to compare the costs of getting each type of loan.