First Miami Tour of Green Houses, organized by Carlos Ruiz and sponsored by AIA Miami and the Miami Association of Realtors:
Our home approaches sustainability as a set of social and ecological concerns. Social sustainability describes the way our house helps foster a sense of community from the scale of family to the scale of the neighborhood. Ecological sustainability describes the range of approaches we use to positively impact the natural environment at the local, regional and global scales.
In terms of social sustainability, our home reinforces the pedestrian nature of the neighborhood by reaching out to the street and park with two porches. The porches – and lack of walls or fences between house and street – are welcoming gestures that are analogous to the way we interact with our neighbors. Our home is a fifteen-minute walk from the shops and movie theaters of downtown South Miami, and a ten-minute walk to the Metro station. The house is also designed as a setting for family life, with an emphasis on the spaces that bring us together. The house is centered on the kitchen, courtyard, dining and living rooms, which all open onto each other.
Ecological sustainability includes a range of concerns, like the amount of energy used to build the home and furnish its materials, the use of energy and water in the daily operation of the house, the durability of the building, the air quality it maintains, and the way its landscape provides habitat for animals and food for our family.
The house minimizes the embodied energy consumed during construction by using recycled materials for more than half of the building above ground, and by using a steel structure, which represents much less embodied energy than a conventional concrete block house. The steel structure and insulated exterior panels also contribute to the house’s durability, as they resist the dynamic forces of hurricane-strength winds, are impervious to termite damage, and inhibit mold growth.
The house uses just one-quarter of the utility-supplied electricity and one-third of the utility-supplied water of a typical house. Conservation is key – we oriented the building so that the windows face north or are shaded by overhangs and trees so that the house is filled with natural daylight but receives very little direct light, thus minimizing heat gain and reducing the need for air conditioning. Artificial light is provided by LED and CFL bulbs, which produce little heat and consume little electricity. The house is well insulated (R-24 walls and R-33 roofs) and sealed, and uses a very highly efficient air conditioning system (22 SEER). A solar hot water heater eliminates another major source of energy use, and Energy Star appliances further reduce the use of electricity.
We generate most of the electricity and water used in the house. A 5kW array of photovoltaic panels on the upper roof provides roughly three-quarters of our electricity over the course of the year. We collect rainwater falling on the upper roof and filter it to make it potable; during the rainy season we don’t use any municipal water. We also collect and filter the water that goes own the bathtub and shower drains, which we then reuse to flush the toilets.
The house maintains a healthy environment by eliminating carcinogenic compounds like formaldehyde (commonly used in plywood) and other volatile organic compounds in materials like paint and adhesives. The building is oriented to increase cross-ventilation when the outdoor humidity is low, and the air conditioning system uses multiple filters to draw dust out of the air.
Our landscape is designed to provide habitat for native species and food for our family. Many of our plants help sustain butterflies, bees and birds, as well as other insects which feed our lizards, toads and other birds. We are cultivating a food forest of fruits, vegetables and herbs, which we fertilize with homemade compost. The landscape is designed to eliminate rainwater runoff (all the paving is permeable) and minimizes irrigation by substituting native plants for the customary front lawn. We designed the lower roofs of the house to hold roof gardens, which we hope to install, soon.
Here are links to our suppliers and contractors.