With the Gulf Stream just a few miles off shore, the Florida Keys present the ideal tropical climate for a passively cooled house—one that stays comfortable without air conditioning. In the first post to his new blog, The Tropical Architect, LEED-certified architect William Hoffman proves it can be done.
For this home in the Keys, Hoffman borrowed some tricks from the Florida Seminole Indians, whose open-sided chickee huts were built on elevated platforms and roofed with palmetto fronds. “The open sides offer free air movement through and around the structure, and the thatched roof offers protection from the sun and rain,” Hoffman says.
Hoffman oriented this house on an east-west axis, with the long south façade situated to capture prevailing breezes that are cooled by the ocean, the treetops and a screened porch on the home’s southeast side. The shorter east and west walls minimize the rising eastern sun and intense setting sun. Roof overhangs shade exterior walls and allow windows to remain open during wind-driven tropical rain storms.
Hoffman prefers open walls with screen protection in tropical settings, where ventilation is necessary most of the year. In this house, a covered screen entry space protects the house from sun, rain, insects and animals while collecting as much breeze as possible. Above the stairwell leading to the roof deck, an operable windowed copula creates a “stack” effect to thermally induce air flow, with additional help from a whole house fan when required. Louvered interior doors and transoms promote air movement through the house. A water-tight, insulated and reflective Galvalume metal roof protects the home from the elements.
While these design tricks go a long way toward keeping occupants cool, Hoffman notes that “intangibles such as state of mind and clothing play an important part of staying comfortable.” To live in a tropical climate without AC, he says, you can’t let the heat of the day enter into your psyche. Wear breathable cotton clothing and a broad-brim, ventilated hat.