[We asked contractor David Jacknin to interview internationally
acclaimed architect, David Hertz, FAIA, a pioneer in the field of sustainability,
whose book on resource efficient design, The Restorative Home, was published last year. The most famous Hertz
project so far, and the cover for his book, is the house he designed out of the wings from a decommissioned Boeing 747. His involvement with the novel Skywater system for drawing water out of the air was described in the July 18, 2016 New Yorker.– Ed.] What are some of your ideas for
lessening the impact of a house on the natural environment? It starts with the idea that a house should give back more
than it consumes. It is possible to
build a house so that it produces more energy than it consumes, that takes
advantage of natural ventilation, natural lighting and that even produces its
own food and water.
Wow, so, how do we break that down
to specific steps a homeowner can take? Start by
picking a building plan that works with your site and then orienting the house
correctly in relation to the path of the sun. It’s also important to understand the prevailing breezes and how the
house can be oriented to take advantage of them. Above is David's dining room in Venice, California where large sliders allow it to become an extension of the courtyard. Recycled and FSC-certified ipe, mahogany, and fir are used throughout the house; the table and benches are made from scraps of wood leftover from making other parts of the house. The sideboard top in the background is his lightweight eco-concrete called Syndecrete.
In some of your articles you mention
embodied energy. What is it and why is
it important? It is
important for people to understand the concept of embodied energy. A material like aluminum, for example,
requires a great deal of energy in its production. If a new building material has a large
quantity of aluminum then it has a great deal of embodied energy. If, however, you repurpose aluminum that is
already in the waste stream and reuse it, this is a big win for the environment. The same goes for other materials. Repurposing has been a big part of
many of your projects. Can you tell me
more about this? Again it’s about
reducing the embodied energy. Our
culture produces a great deal of waste both at the manufacturing level and then
at the landfill level. By taking
something out of the waste stream and using it in the production of a house,
one is upcycling or giving the
material a higher and better use. This
can be done by using reclaimed flooring, lumber, doors, windows and hardware.
Your book talks
about energy generation, what are some of the systems you have used? We use PV Photo Voltaic panels to produce electricity and flat plate and
parabolic tube collectors to heat water.
Parabolic collectors are an efficient way to heat water in a small
space. Heated water then supplies
the radiant heating system embedded in the floors. We also employ
passive techniques to heat the house. By
orientating thermal masses towards the sun, the concrete absorbs energy during
the day and releases it slowly at night. What other
techniques do you use to control temperature? Many of our designs include a solar chimney
which uses convection currents to exhaust and control heat. We also use thermostatically controlled
skylights and windows to take advantage of natural ventilation and to control
temperatures. You’ve described
your concrete product as a “contemporary terrazzo made from our waste
stream.” Can you tell me more about
that? Syndecrete
is half the weight of normal concrete with a much higher compression strength. It
is
also made from 41% recycled materials, such as post consumer carpet fiber as reinforcement. Syndecrete is composed
of a high volume of fly ash and uses materials extracted from the waste stream as decorative aggregates like recycled bottle glass, plastic regrind, electronic parts, etc. This is a good example of a way to make the
house more resource efficient.
How about the claim that you make water out of
air and your use of “living walls”? I am very excited about
my association with Skywater. Skywater
is a patented atmospheric water generator
that makes water from air. With the Skywater system, homeowners can
produce their own pure drinking water at home, even using solar energy. Our designs also include vegetative walls including aeroponic food
towers that can grow a high volume of vegetables in a vertical space with a
much lower volume of water. Such a system gives homeowners immediate
access to organic food and helps create a sustainable and restorative
environment. What other steps
are you taking to protect the environment? We
make sure the woods we use are FSC certified and are harvested in a sustainable
way. We also pay attention to indoor air
quality by using zero VOC paints and designing the house to maximize natural
ventilation. What about cost…
this all sounds expensive? By using repurposed
and locally sourced materials houses often end up costing about the same amount
per square foot as conventional construction methods. Operating costs are much lower as the houses
produce their own energy. How do you think
your work can impact the larger building industry and the way people live? I’m hoping that my work can help influence
others to consider embodied energy, human connections to the natural world and
our place in it.
