Interior concrete floors tend to be cooler regardless their location, but not like outdoor concrete. In new construction, particularly loft renovations, etc., concrete flooring is heated, which makes it cozy. A concrete floor in Washington is no different than a concrete floor in Florida or Texas. It has more to do with construction, the heating system and insulation of the house.l

Radiant flooring is an option if one has an existing concrete floor. The radiant flooring system is installed underneath the concrete floor to heat the concrete.

The carpet and pad are insulating you from the concrete floor.

You can. You start by applying moisture barrier to the concrete--flooring stores have it--then gluing the hardwood to the concrete.

there are a lot of comparisons regarding concrete floor finishes that you can find online here is one example http://www.concretenetwork.com/concrete/polishing/ there you could a lot of floor concrete that you can compare to other.