You could either ask a very good local real estate professional or appraiser. I'd ask friends, family, colleagues for local real estate professionals they've used recently and been happy with. You might also contact a real estate attorney or your local mortgage professional for the name of an appraiser they trust & do business with that might also be willing to review the changes you have in mind. Some of these ideas are free, others are sometimes a nominal charge. They'll give you an idea of what your place is worth and what your ideas of improvements might bring for you.