A NATURALLY COOLED FLORIDA HOUSE

Enlarge Image Image Gallery

Although it cost non more than a comparable "surface" structure, this earth-sheltered home satisfies the majority of its own heating and cooling needs

In north Florida's subtropical panhandle region—where summertime humidity can average a clammy 82%, and temperatures in the 90's aren't even considered noteworthy enough to comment on—cooling a dwelling is usually of greater concern than is warming it. On the other hand, though, heating requirements can't be ignored altogether , since the region is subject to nearly 1,600 heating degree-days during its cold season.

Understandably enough, designing a passive solar home to suit such fluctuating conditions could present quite a challenge . . . but the folks at Tallahassee's Mad Dog Design and Construction Company felt that, by taking advantage of several "tried and true" locally popular building techniques and coupling them with modern thermal conditioning methods, they could come up with a house that would be comfortable throughout the year . . . but which would require little or no utility-supplied power for heating or cooling.

A WELL-PLANNED DESIGN

Essentially, the Florida builders used several passive methods—backed up by two active systems—to insure a pleasant interior climate during the hot summer months. First and foremost, the earth-sheltered structure relies on natural ventilation, combined with heat-gain prevention, to maintain a comfortable internal environment. Borrowing from traditional local designs (which, of course, evolved to suit the area's climate), the Sunshine Staters utilized high ceilings, continuous attic-linked soffit vents, and strategically placed windows to encourage the flow of air throughout the house.

For example, the south-facing solarium/greenhouse area incorporates ceiling mounted outlets that can be opened, in case of overheating, to allow warm air to duct into the attic and out the soffit vents. Similarly, in the house itself—which is separated from the solarium by a quartet of sliding glass doors—unwanted warmth can be vented around four movable 8' X 8' insulated ceiling shutters. These horizontally hinged overhead "flaps" are mounted in light wells which are framed into the front of the attic and faced with acrylic glazing. When the electrically operated sky shutters are three-quarters open, pockets are formed, which accumulate warm air and direct it upward . . . while permitting plenty of indirect light to brighten the rooms below.

Other heat-controlling elements in the unique design include [1] roof overhangs above the skylights, [2] solar screening over the greenhouse windows during the warmer months, [3] insulated draperies on the sliding glass doors, and [4] ceiling insulation with an R-value of 28. Additionally, the builders have taken advantage of deciduous trees to help shade the structure in the summer months.