Raymon Gerard (plaintiff) had a daughter suffering from cystic fibrosis. Her condition required Gerard to purchase an air conditioner in order to control the temperature and humidity of her room. However, because the air conditioner only regulated the temperature in her room, the daughter was forced to stay in the room all day, which was psychologically damaging to her. Her doctor advised Gerard to purchase a central air conditioning unit so that his daughter could freely walk throughout the house. Gerard paid $1,300 for the unit. The addition of central air conditioning to his home increased the value of the home by $800. Gerard deducted the entire cost of the unit as a medical expense under section 213(a). The Commissioner (defendant) disallowed the deduction.