I have a one level home with a fairly flat roof, crawl space, electric forced air wall heaters, and in the winter when it gets cold, the humidity levels go crazy high. The roof is only two years old and does not appear to be leaking. The crawl space has a concrete floor and not a whole lot of crawl space vents. The walls have a little insulation we can see when we open up the plugs. The roof, well it is hard to tell. Not very thick though so it doesn't have too much insulation. Keeping the place warm in the winter is very expensive and in the summer it gets quite warm so I assume the insulation above is not great. We need to get the humidity levels down though as it is actually pooling at the bottom of the windows. It is beading on the windows, almost all new double paned windows, hardiplank siding (both windows and siding installed before we owned it but we checked and it is papered under the siding.) Now, one weird thing is the sidewalk comes right up to the siding on one half of the house. It is almost as if someone raised the level of the ground at some point, as the neighbor is lower as well. The humidity levels at the other end of the home are just as bad though, if not worse. We do have a hard time heating the place though. What do you recommend? Should I add insulation to the roof? If so, how?
Should I tear out the sidewalk around the part of the house? If so, the grade would slope toward the home...
Should I add vents to the basement? I actually did put in vents in the basement on the one side where the sidewalk covered the old vents this summer but it is not helping the condensation this winter. The windows right above the vents are still covered with condensation.

Are we just not keeping it warm enough?

Any advice?

Thanks!

Oh, and I did put black 6 mil plastic over the concrete in the crawlspace last spring. Did not help it this winter...