Why do I have condensation on ceramic tile floors when the heating system is off?

I have a geothermal system, which is turned off for the summer. The cooling system is on but not running at this time. My home is ICF (Insulating Concrete Forms) and I have a panel deck as the floor base. Last summer both the kitchen and bathroom (tile floors) were slippery with condensation. This year only the bathroom floor is very wet. The room is also very cool. I have tried opening windows, turning on the electric fireplace but nothing dries it out. What could be causing this? I thought it might be the membrane, but it doesn't affect both rooms and it didn't do this prior to the installation of the central air conditioning system and air exchanger last year. 

Suzanne,

You are experiencing a typical problem of buildings that stay cool without the use of air conditioning. Your ICF building has a high thermal mass, which is a great thing...