The Green House of the Future Includes GSHP

The Wall Street Journal asked architects to draw up plans for the most energy-efficient houses they could imagine. They imagined quite a bit.

By ALEX FRANGOS

What will the energy-efficient house of the future look like?

It could have gardens on its walls or a pond stocked with fish for dinner. It might mimic a tree, turning sunlight into energy and carbon dioxide into oxygen. Or perhaps it will be more like a lizard, changing its color to suit the weather and healing itself when it gets damaged.

Those are just a handful of the possibilities that emerged from an exercise in futurism. The Wall Street Journal asked four architects to design an energy-efficient, environmentally sustainable house without regard to cost, technology, aesthetics or the way we are used to living.

The idea was not to dream up anything impossible or unlikely -- in other words, no antigravity living rooms. Instead, we asked the architects to think of what technology might make possible in the next few decades. They in turn asked us to rethink the way we live.

"This is a time of re-examining values, re-examining what we need," says one of our architects, Rick Cook, of the New York firm Cook + Fox. "We are re-examining the idea of home."

A fresh look may be long overdue, given the amount of damage that homes can do to the environment. It's easy to envision a power plant spewing pollution or a highway full of cars burning billions of gallons of petroleum. But buildings -- silent and unmoving -- are the quiet users of much of our energy, through electricity, heating and water consumption. The U.S. Energy Department estimates buildings are responsible for 39% of our energy consumption and a similar percentage of greenhouse-gas emissions.

The growing awareness of that fact helps explain why green building is one of the most pervasive trends in the construction industry -- even as the economy struggles and home-building is at its lowest level in a generation.

So, how will the green homes of tomorrow help solve the energy puzzle? Here's a gander into the future.

"I'd love to build a house like a tree," says architect William McDonough of the Charlottesville, Va., firm William McDonough + Partners. And that's what he set out to do here.

The surface of his house, like a leaf, contains a photosynthetic layer that captures sunlight. Unlike today's solar panels, which are often pasted above a roofline, these are woven into the fabric of the exterior. They heat water and generate electricity for the home -- and create oxygen for the atmosphere, to offset carbon produced in other areas of the home.

Mr. McDonough envisions a sleek, curved roof with generous eaves to provide shade, which lowers the heat load in summer, thereby reducing the need for energy-hogging air conditioning. The roof also insulates and provides an outdoor garden. (Mr. McDonough designed a similar "green roof" for a Ford Motor Co. factory -- one of the first large U.S. buildings with that design.)

The "bark" of the treelike house would be thin, insulating films that would self-clean and self-heal, Mr. McDonough says, thus avoiding the need to replace them after years of exposure to the elements.

William McDonough + Partners envisions its house like a tree. The "bark" of the house is made up of thin, insulating films that would self-clean and self-heal if damaged. A curved roof with large eaves provides shade, which lowers the heat load in summer. The "trunk," or the frame of the home, consists of carbon tubes, while the "roots" are a heat-pump system buried in the yard.

It sounds far-fetched, but some of these technologies already exist. Self-cleaning glass, for instance, has a special coating that uses ultraviolet sunlight to break down organic dirt; rainwater then washes the filth away.

Self-healing paints that contain microscopic capsules of color are in use on some car paint, for instance. These vessels break open when the surface of the paint is scratched to repair the damage. Similar ideas could expand to repair other materials such as glass or cladding.

The "trunk" -- or the frame of the home -- would eschew wood or metals. Instead, lightweight, "resource efficient" carbon tubes would keep the structure standing upright.

Finally, the "roots" of the home would be a ground-source heat-pump exchange system buried in the yard. It would take advantage of the relatively constant temperature of the soil to control the home's climate -- bringing in heat in winter, when the ground is warmer than the surrounding air, and cool in the summer, when the ground's temperature is lower. Such systems exist today, but cost puts them out of the reach of most homeowners. (Until GroundSource Geo debuts next year...-ed.)

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