Guest chambers and unused rooms must be kept dry, aired, and heated to prevent health risks.

Original passage

The guestchamber should have equal care with the rooms intended for constant use. Like the other bedrooms, it should have air and sunshine, and should be provided with some means of heating, to dry out the dampness that always accumulates in a room not in constant use. Whoever sleeps in a sunless room, or occupies a bed that has not been thoroughly dried and aired, does so at the risk of health, and often of life.