Kendall house is a model of efficiency
Posted on Sun, Sep. 09, 2007
BY GEORGIA TASKER
ALEX KOLYER / FOR THE MIAMI HERALD
Albert Harum-Alvarez and his wife, Enid, are building a home with a low environmental footprint.
Albert Harum-Alvarez, a software designer and consultant, grew up in Kendall and has spent years planning his home among the trees. Now under construction, it will catch the southeast breezes, use a geothermal pump for optional air conditioning, and employ a composting toilet system. Harum-Alvarez believes it's the greenest home in Miami-Dade County.
Harum-Alvarez and his dancing teacher wife, Enid, wanted to save the site of the historically designated oldest house in Kendall, in which the family now is living. They also decided to build an energy-efficient Key-West style home that would face it across a walking and bike path that runs through the property but not have a larger footprint than the cottage's 1,100 square feet.
This two-thirds of an acre was never divided. The Harum-Alvarezes want to keep the feeling of a long-ago country setting.
''I wanted to design a beautiful home for my family that could be a model for building homes in Miami,'' he says. ``Green design is really nothing more than good, elegant design, and sustainability is just a broader way to talk about affordability.''
Because he wanted to keep the property roadless, and because he is including some unusual features in the home, he has encountered some bumps along the permitting route. For example, the county insisted Harum-Alvarez built a standard septic system in case the composting toilets didn't work. Yet, Miami-Dade County will expedite permits for green buildings, which at least put him at the head of the line.
The Harum-Alvarezes sketched out their plan and elevations and took them to architect Gene Farmer. Albert, 46, is acting as his own contractor. John Rogers is his builder. The 2,300-square-foot home is oriented to catch southeasterly breezes, with the long axis running east and west. The first and second floors have wrap-around porches for shade, with extra tall windows for ventilation. A central stairwell acts as a solar chimney, pulling hot air up the stairs to the cupola, where it escapes.
Because the site is sandy, Harum-Alvarez was able to excavate a basement, which allows space for the composting toilet system.
Walls are made of poured concrete using insulated concrete forms with an R-value of 54. The R value measures the resistance to heat transference, so this castle-wall thickness will keep the interior cool in summer, warm in winter. The forms have Styrofoam on either side of the concrete, making them resistant to heat gain and loss as well as noise transference.
Insurance costs are reduced because the walls can withstand 200-mile-an hour winds, and energy bills may be cut in half. A special cool-pigment metal roof reflects certain wavelengths of light, also reducing the heat load of the house; a radiant barrier beneath the roof reduces heat buildup even more.
Another feature to help reduce energy costs is an exposed concrete wall in the living area that Harum-Alvarez calls a thermal flywheel.
''It has a rough surface and can absorb humidity and give it off again,'' he says. ``It moderates the temperature.''
Solar panels on the south side of the roof will provide hot water.
The laundry room is not a part of the air conditioned space, but is just beyond the kitchen on a back porch. This will keep heat from the washer and dryer out of the house. The kitchen has the tallest ceiling in the house with dormer windows to pull out all cooking warmth from the room.
Three bedrooms and two bathrooms upstairs all have windows, transoms and extra tall ceilings. The children's rooms also have access to a sleeping porch on the east side of the house that looks into the tree canopy.
One of the most interesting green components of the home is the toilet/composting system. Waste will be converted ultimately to soil and used in the garden.
The toilets are ultra-low flush, the same units used in yachts, Harum-Alvarez says, so they flush with as little as a pint of water. That water is drained from the bottom of the composting unit. At this point, Harum-Alvarez says he and his wife are considering whether to handle the water through the septic system or a gray-water garden.
The composter has four compartments that rotate, so as one fills, a next can receive the waste. By the time the fourth compartment fills, the first can be emptied with a small shovel as composted soil.
The family also opted for the geothermal cooling/heating pump.
John Moore, one of the owners of Hi-Tech Air Service, worked on the air conditioning system for the home. He explains that a condenser takes heat from coils and discharges that into air. In a geothermal unit, relatively cool groundwater is pumped through a tube within a tube, taking the heat from freon and exchanging it with coolness from the water, then returning the water to the aquifer.
The cost is less than a standard system, Moore said, but there is the added expense of digging two wells and the pump needed to circulate the water.
''I'm sure he'll use a high efficiency pump, so yes, this will save money,'' Moore says.
Native landscaping includes preserved oaks and gumbo limbos, and along the eastern side, a to-be-planted native hammock. The original cottage will remain, perhaps to be rented.
On this unusual construction site, there is no Dumpster stacked sky-high with old boards and waste. Instead, there is a basement neatly stacked with used lumber and plywood, awaiting some future use.
They even have a plan for electric outtages.
''We hope to get an electric car,'' Harum-Alvarez says, ``and during power outtages, the batteries could supply the refrigerator.''
Costs aren't in yet because construction is ongoing.
''We expect that both our design costs and hard costs in building will be higher than the average,'' Harum-Alvarez says. ``We are essentially front-loading our expenses, so that the running costs of our household are reduced in the future.''
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Video | Building a green home
