When David Horobin heard the words, “I’m going to make you an offer you can’t refuse,” the words weren’t coming from Don Vito Corleone but from Nick Federoff, a television and radio host, whose shows include “Things Green” on PBS.

What Federoff envisioned for Horobin, a Napa resident and co-principal of Estudio Verde Architects, was a spin-off of “Things Green” — but this one would be called “Things Green House.”

How had Horobin, a Welsh-born, Oxford-trained architect and inventor, inspired such an idea?

Horobin has been building “green” for nearly five decades, winning both state and federal awards in energy and sustainable design.

“Green and sustainable is an integrated design philosophy in the European architectural schools,” Horobin said. “It’s the responsible way to design buildings and has been in my blood since college. My dad used to tell me stories of ways they survived World War II in the U.K. and how many of the ideas would now be considered sustainable. Transfer that philosophy into peace time and you have a responsible stewardship of our planet for us to hand down to future generations.”

Thirty years ago, Horobin discovered a German product that supported such a mission: IsoRast, an I.C.F. (insulated concrete form) used for building structures in multi-beneficial ways. The form, (think of a u-shaped mold), was made of foam instead of concrete and was, therefore, much lighter than traditional concrete blocks. And, because it was lighter, labor and construction was easier, faster, and less costly. It also offered long-term aesthetic and maintenance advantages.

“Fundamentally, IsoRast spoke to my inherent goal of building with environmentally-friendly, energy and resource-efficient materials,” Horobin said. He soon enhanced and redesigned it to meet American standards and created his own forms called SmartBlock for buildings and H-Forms for landscaping.

Using foam in this case doesn’t contradict Horobin’s sense of building green, because his blocks are made of a type of polystyrene that does not contain chlorofluorocarbons. In addition to being superior in quality and easy to assemble (like Legos), they produce almost zero waste and are highly fire-resistant.

The forms are also flexible which allow for a wide variety of design options such as Horobin’s complete H-Form system for exterior elements — fences, retaining walls, sound walls, privacy and security walls, patios, water features, and swimming pools. These landscaping features are what eventually led Horobin to his Godfather moment and PBS series.

It was at the 2015 Landscape Industry Trade Show in Ontario, while displaying his H-Form system, that Nick Federoff first approached him. Curious about the forms, and equally passionate about sustainable design, Federoff said, “It’s a shame that you can’t use these for building houses” to which Horobin replied, “I have. Hundreds of them in several subdivisions.”

The seed was planted. At the time, Federoff had been planning to add 1,600 square feet to his own home in Whittier, Calif. After meeting Horobin, he not only wanted to collaborate with him on this addition, but also wanted to use his H-Forms. From this grew the idea of “Things Green House.” Federoff successfully pitched it to PBS as a 13-part series that would take viewers through the design and building process using his own home as the example.

According to Federoff, “Things Green House” will take a true representational and education approach, unlike many HGTV and reality shows where homes are unrealistically designed and built with an inconceivably low investment.

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The series will cover topics such as explaining the benefits of using an architect, how an architect conceives a design, and how design and construction decisions are made. It will interview manufacturers about their products. It will also explain how to marry materials for safety, health and energy efficiency, how to minimize the cost of heating/cooling systems, how to orient one’s house, and how to maintain and sustain it.

To date, the design has been completed and the filming of “Things Green House” has begun. The first show is planned to air on KQED mid-February.

Federoff and Horobin have already discussed Season 2. Their goal is to find and purchase a suitable piece of property in the Napa Valley on which to build an integrated house, landscape, and edible garden using H-Forms and all green materials and strategies. They plan to create one of the most sustainable homes in the country.

There are even plans for a third season of “Things Green House” and beyond. These shows will be the same as Season 2 but with sites in different parts of the country. After meeting the environmental challenges and goals of the Napa Valley, the team will go on to address different concerns in states with varying climates and topographies such as topical hurricane-prone areas.

Contact Horobin at Estudio Verde Architects at (707) 337-4144 or email dhorobin@earthlink.net.

Patti L. Cowger is a credentialed, award-winning Napa-based interior designer and owner of PLC Interiors. For more information about her design services, visit her website at plcinteriors.com call (707) 322-6522; or email plcinteriors@sbcglobal.net.