In the Fleming house, a new high velocity heat pump system and a refrigerant coil connected to a condenser on the roof were installed to heat or cool the house according to the season. Because the house has no basement, the water heater was located in the attic on top of a safety pan connected to a drain to head off possible leaks. Quick, convenient copper pipe was used to connect the water heater to pipes in the rest of the house.

The house also incorporated passive cooling—the use of building materials and design to prevent hot air from entering the home in the first place. Ventilation from windows, wall vents, and other nonmechanical sources helped disperse heat produced by ovens, dishwashers and other appliances. The Fleming house had 16-inch thick exterior brick walls that slowed and dissipated heat as it moved inside. Outside, vines, shrubs and overarching oaks shaded the walls all year. Inside, twelve-foot-high ceilings took advantage of the natural upward flow of hot air to keep rooms cool. But, while passive cooling lowered temperatures, it did little to mitigate humidity. As a result, air conditioning was essential.

To calculate the cooling load—the amount of central air conditioning needed to keep the Fleming house at an average indoor temperature of 75 degrees—This Old House used a standard industry formula that took into account the number of occupants, the size of the house, the amount of insulation and the number of windows, doors and other sources of ventilation, including kitchen and bath fans. It also factored in a worst-case scenario: the system should be able to handle a 93 degree day at 90 percent humidity. The resulting figure was expressed in tons. (In the early days of air conditioning, the load was calculated according to the fact that it takes 12,000 BTUs to melt a ton of ice.) The Fleming house was large and Savannah humidity levels high, so three heat pumps provided the necessary 13 tons of cooling capacity—3 tons on the garden level,and 5 tons each for the top floors. Air circulated in the house through unobtrusive, 2-inch diameter outlets.

Attic Access
Up on the Roof

2nd Floor:
Guest Bedroom | Guest Bath | Bedroom
Laundry | Master Bedroom | Master Bath | Attic