After a trip to Mesa Verde, he considered how ancient peoples built their dwellings to maximize the sun during the winter months and block the heat during the summer. “We visited in the middle of June and took a picture at 2 p.m.,” he recalls. “Later, it occurred to me that the dwelling was in full shade in the middle of the hottest part of the year because of the 12-foot overhang. They knew exactly how a south-facing house in the summer doesn’t get sun because of the overhang, and how in the winter the sun can reach back into the cave and heat the rock, which radiates the heat back at night for free.”

He wanted to do something similar. The Fortunatos and their team eliminated the need for air conditioning by installing a five-foot overhang along the roof, which shades the home in the summer. In winter, sun through double-pane windows on the southwest wall heats the living spaces. The garage is heated passively via a window in the insulated garage door.

A chimney in the stairwell ventilates the house; warm air rises naturally and leaves through vented skylights and a window. The team used ThermalCORE phase-change drywall on many of the ceilings and on the living-room wall to help regulate room temperatures.

The house was also super-insulated. Behind the ThermalCORE drywall are 2 “x4” framing filled with cellulose insulation and two layers of staggered BlueRidge fiberboard sheathing. The structure is air sealed. The TPO roof with a .46 reflectivity factor has an R28 value.

The Green Idea House has two drain-water heat exchangers. Upstairs, as hot water from the shower goes down the drain, a RenewABILITY Power Pipe transfers the heat to the cold-water pipes supplying the shower (a vertical drop). Downstairs, an Eco-drain hot water heat exchanger does something similar, but over a horizontal run.

The key to affordably renovating the house was to think holistically, Fortunato explains. “The overhangs, insulation, and air sealing heat and cool the house naturally. Their cost, then, would be more than offset by the smaller mechanical heating and cooling systems that needed to be installed.”

Solar-Powered Electric House 

Twenty-six photovoltaic solar panels were oriented to the southwest and produce 6.5 kW of electricity. At $18,000 after rebates, Fortunato says, they were the family's biggest expense. “Today, those solar panels cost 50 percent less, so there’s no reason not to do solar now.”

In the garage are two GE heat pump water heaters with an efficiency of 238 percent. One heats the domestic hot water. The other works with the space-heating system. Insulation and burners were stripped off the old gas hot-water tank, which is now used to preheat city water.

Other sustainable strategies used during the renovation include using FSC certified lumber in the framing. Eighty-year-old redwood salvaged from a Los Angeles building is now the living room ceiling. Recycled permeable Stepstone pavers form an outdoor path. Inside are recycled tiles from Oceanside Glass and Stonepeak. 

Moreover, the project recycled 97.5 percent of the demolition waste. The team used existing lumber when possible. A patio was busted up and the material used for garden walls. A 1,200-gallon tank captures rainwater used for landscaping.