My basement is an old (more than 50 yrs) poured concrete basement, unfinished, no water issue but has lots of effloresces (moisture issue). It is a dry "warm" basement in the winter and dump "cool" basement in the summer (didn't use dehumidifier yet). There is no heating during the winter but the temperature always keeps at the range of 52 - 62 degree all year round.

I am thinking about finish it and have done lots of research about how to do it. I agree the rigid foam for wall and floor is the best way to go for the insulation. A well insulated basement is good to eliminate condensation in the summer but it is NOT good to get the temperature from the ground during the winter. I am worrying that we have to put heating system in the basement to avoid pipe frozen during the long winter after the insulation (in MA). If that is the case, why we need to insulate it so well?

How about the summer, do we need air conditioner down stair after the insulation?

Worry about condensation during the summer for an un-insulated basement? Use dehumidifier to keep a dry environment may be enough.

So if we think 52 - 62 degree is good in basement, we can just finish the basement without any insulation and vapor barrier. There will be no moisture and condensation problem in winter. During the summer if the dehumidifier works as expected, there should be no moisture and condensation issue as well.

What's your experience and opinion about this?