The Off-Grid Guest House’s unique setting brings special constraints but rich rewards. Surrounded by phenomenal views with red-tailed hawks soaring over beautiful ridgetops, it’s situated on a serene and highly sought-after piece of coastal Santa Barbara County, California.

So when the clients asked for a design that was sensitive and responsive to that special setting, architect Dan Weber at Santa Barbara–based Anacapa designed a home with generous use of sliding glass and decks that cantilever over the hillside, offering sweeping views of the surrounding hills and the Pacific Ocean.

The Off-Grid Guest House makes generous use of sliding glass and decks that cantilever over the hillside to offer sweeping views of the surrounding hills and the Pacific Ocean.

But responding to the setting also meant being sensitive to the neighbors and the environmental concerns of the land surrounding the home. “The character of the house is really a product of the owners’ sensitivities and goals, and matching with our design aesthetic,” Weber says. Although it’s located in a small space on a very exposed site, the 800-square-foot house is tucked into the hillside and covered with a green roof, allowing it to almost disappear into the hillside when viewed from above.

And the home’s remote location also meant that making it self-sufficient and sustainable was a primary goal of the project. Connecting the dwelling to electric power, sewer, and natural gas services was prohibitively expensive, with a price tag in the hundreds of thousands of dollars. So the guest house is off the grid, creating all its own power through the use of solar photovoltaic panels, a battery storage system, and propane for heating and backup power.

The home is located on a working cattle ranch with a land conservancy and a homeowners association made up of about 100 single-family homes. The homeowners association has a stringent design review body that created a huge design constraint for the home.

“That is a pretty primary goal of the project, is to figure out how to make a house that’s efficient enough that it can survive on its own,” Weber says. So while the home’s energy performance is strong enough that it can generate all its own power and meet California’s stringent building codes, Weber says the efficiency wasn’t driven simply by environmental motivations. “It was more driven by the target of what’s sustainable over the long term for these property owners and for that site.”

Off-grid power generation

While the design team determined early on that connecting to the power grid wasn’t feasible, they also knew that the cost of combining solar power with propane would be quite reasonable. “In rural residential projects, that’s just the status quo,” Weber says. “Everyone uses propane because it’s really reliable and the cost is low.” The propane option became even more attractive on the sensitive site when Weber found out he could use underground propane tanks. “I was surprised it was really not that expensive to do a subterranean propane tank.”

Due to its remote location, the house has its own well, a high-performance septic system, and a solar photovoltaic array supplemented by battery storage and a backup propane generator.

The propane supply fuels a backup generator, a key amenity for quality of life in an off-grid home, where managing power usage becomes a daily grind. “They don’t want to ever have the scenario where they had a week of cloudy weather and their batteries on their PV system have been drained and they can’t turn on the lights or run their music because they don’t have enough juice in their battery system left,” Weber says. “So it kind of is just a necessity for comfortable life in a location like that to have a backup system.”

Solar panels are also not 100 percent reliable, Weber notes, and when they fail or need maintenance, homeowners prefer to keep the lights on while they wait for repairs. This guest house automatically switches over to the generator when the batteries drop below a certain level and runs on the generator until the panels begin producing power again. “It’s just a management-free, seamless system,” Weber says. The generator runs a limited number of circuits in the home to extend the fuel supply as long as possible.

Radiant heat for comfort and cost savings

Thoughtful use of propane for the home’s space-heating and water-heating systems also helped avoid the expense of an oversized photovoltaic and battery system. Instead of the larger, more costly solar array that would be needed for electric space heating and water heating, the home uses propane tankless water heaters that provide both domestic hot water and radiant heat in the concrete slab floors. It’s a solution that’s much more efficient in terms of upfront cost.

Radiant floor heating supplied by propane tankless water heaters balances the coldness of the home’s concrete floors.

“There are those rare clients that really want to try to make everything photovoltaic, but the vast majority of clients, the number one consideration is the upfront installation cost,” Weber says.

The heating solution also offered comfort and design advantages. Weber says his clients love the luxurious feeling of radiant heat, which balances the coldness of the home’s concrete floors. The propane tankless water heaters are very efficient. And because the home forgoes air conditioning in favor of cool ocean breezes, the designers were able to eliminate ductwork entirely, a choice that works well with the home’s flat green roofs. “It’s hard to squeeze big ducts up and get a house that’s designed like this,” Weber says.

The home also utilizes propane for its clothes dryer and stove, the latter of which is a key feature in every high-quality single-family project, Weber says. “I would say out of all the houses that we’ve done, maybe 1 out of 50 has used anything other than a gas or propane stove,” he says.

Weber and the Off-Grid Guest House design team have won multiple American Institute of Architects awards for the project, highlighted by the national AIA Housing Award. He attributed the recognition to a variety of factors coming together — a great site, great architecture, great interior design, and great photography — but also a home with a good story. “I think when people look at this house, they can see how sensitive it is at responding to all those various constraints,” Weber says. “It just has a lot of soul.”

All photos by Erin Feinblatt.