I have a main floor bathroom with a jacuzzi tub, the tub is so cold during the winter it is useless. There is insulation in basement joist and the basement is heated as well. I took a piece of the marble skirting off and looked underneath the tub and it was extremely cold. I placed a thermometer under there and it showed 33 degrees when the outdoor temp was 28. the outside walls are visible properly insulated. Can't figure out where the cold is coming from. So.....any suggestions? Can i blow in insulation all around it or would that cause the motor to overheat?