When my friends and I rented a house in college, we were thrilled to move out of the dorms. We finally had a place to park our cars, our own yard, and a full house all to ourselves. Although the house was extremely old and sort of run down, it had four bedrooms, two full bathrooms, and a big kitchen. We couldn’t wait to invite friends over and have parties. The rent was really cheap and the location was perfect, but we were responsible for utilities. My roommates and I agreed to be very conservative with thermostat settings. We decided to only use the air conditioner and furnace when absolutely necessary. We threw a party in late September, and the weather turned unseasonably hot and humid. With fifty people packed into the house, it got horribly overheated and sticky. We first tried opening the windows, but the majority of them were painted shut. We then set up a bunch of box fans, but they kept blowing fuses. With no other choice, we lowered the thermostat and started up the air conditioning. We expected a flow of wonderfully cool air to circulate and keep everyone perfectly comfortable. Instead, we got warm air that smelled musty, and a whole bunch of dust. I think the air conditioner actually made the house warmer, and everybody started feeling sick. The house smelled so bad, we had to move the party outside, into the hot sun and humidity. After that, we were a bit scared of starting up the furnace for the first time. We called the landlord and claimed we were worried about safety issues. We were relieved when he agreed to send an HVAC technician to service the heating system.