There is a moldy, musty smell coming from our great room in the past
week. We cannot find any outward signs of mold, either in the room
itself or in the crwal/storage space that the room sits on. The room
is insulated, but we kept the heat off for most of the winter to avoid
heating costs (this was our first winter in the house, the previous
owners kept it heated all year as far as we know). We've seen no
signs of water or dampness (again, either in the room or underneath),
the only source of moisture I can think of is from the washer/dryer in
the hallway adjacent to the room -- but presumably there would be mold
close by?

Is it possible that mold is underneath the carpet? If so, does this
mean the carpet must be replaced? Does it also mean was must keep the
room heated in future winters?

Thanks,
Jeff