“This Old House” is the mother of all home improvement TV shows. Though in recent years entire networks such as HGTV and DIY are devoted to home design, decorating, renovation, construction and real estate, “This Old House,” debuting on Boston’s public TV station in 1979, was the first.

In 1989, original host Bob Vila was replaced by Steve Thomas. Thomas, a California native and graduate of Evergreen State College in Olympia, Wash., stayed with the job through 2003.

Before joining the show, he had done boat carpentry and sailing, and in the early 1980s, traveled to Satawai, an island that is part of Micronesia, to study “star path” navigation from a native master navigator.

After “This Old House,” Thomas, 61, worked on a similar-themed show, “Renovation Nation,” and on programs on The History Channel. In 2011, he joined with an organization he believes can change the world—Habitat for Humanity International.  Working with Habitat has taken him around the nation and the world, but Maine is home.

“Habitat for Humanity ties in with the core of who I am, and how I see myself,” he said, working to improve life for the 1.6 billion who live in poverty housing.

In the early 1990s, Thomas and wife Evy rented a house for two weeks on Monhegan Island, “and really fell in love with it,” he said.

“Maine has a way of getting under your skin. It’s the extraordinary mashing together of the land and the sea and the sky and the islands,” he said.

That experience led to the couple buying and renovating a house on Hupper Island, just off Port Clyde.  They later sold it to summer resident and built another house nearby on the island.

“We needed a shore base,” especially in the winter when crossing by boat can be hazardous, so the couple purchased a small shingle-style Victorian, built in 1905, adjacent to the Port Clyde Post Office. That’s where The Working Waterfront caught up with him for a tour, and later, a sit-down interview in a house the couple is renting just down the road.

WW: In the ’50s and ’60s, people often hired contractors to build houses and improve their homes, but that changed in the early 1970s. People got more involved with the “do it yourself” thing. Where do you think that comes from, that impetus to do it yourself, at that time?

Thomas: I’m part of that “do it yourself” [era].  I bought a house when I was still in college and renovated it and sold it. My dad used to buy, renovate and sell houses, not so much as a professional, but because he had six kids and he needed to house them all.

I think it coincided with back-to-the-land, back-to-reality, back to a different value system than the “establishment.” It wasn’t really a hippie thing, but gardening became really popular at that point. In 1974 you had the first oil [price] shock, so in part, it was reaction to that.

It was one of these periodic waves of back to “reality.” Which you’re seeing again, with the twenty-somethings you’ve been covering. They have the same values. Their value system coincides with the value system of their parents.

WW: You mentioned the energy crisis, and that actually was my next question. We’ve had these energy crises in the ’70s which spurred some interest in efficiency. But it seems like there have been bigger leaps forward in the last ten years or so in energy efficiency and innovation. Do you think that’s true, and what do you think is next in that whole realm?

Thomas: I think right now it is technologically possible on a modest budget to create a net-zero house. There’s a firm up in Belfast, G-O Logic, that’s doing passive houses that require nothing other than the equivalent of a hair dryer to heat.

The technology is there in terms of envelope technology—insulation, windows, insulated foundations and so on—and the heating and cooling technology is there with these inverter-driven heat pumps.

The big break-through was when the Japanese figured out how to convert AC to DC and used DC motors. That really brought the operating costs of driving heat pumps way down.

All of these manufacturers just hone the technology until now it’s really efficient.

There has been a swing in this direction, but the accounting for energy efficiency is faulted. People say it’s too expensive. Well, it depends on what your time horizon is. If you look at the cost of a house over its life cycle, which is 60 to 100 years, then it’s tremendously cheaper to build an energy efficient house than one that’s not energy efficient. So a mental shift has to occur.

I led a seminar a couple of years ago at Greenbuild and the purpose of the seminar was to try to figure out why green building—energy efficiency building, net-zero building, whatever you want to call it—wasn’t more widespread. And I think all of us participating in the seminar figured that, “Well, it’s because the consumer doesn’t get it, or the builder doesn’t get it.”

And we were all wrong. What we found was that one of the big drivers was the lack of the ability to finance green building. The banks don’t get it. Or can’t get it.

Why is it that a $100,000 home theater has the equal weight, in terms of the ability to finance it, as $30,000-$40,000 worth of energy upgrades that will reduce the energy cost to that house to zero? 

WW: Photovoltaics, or”¦?

Thomas: Well, start with insulation. If you look at the energy pyramid, as I call it, the base is conservation. Turn off the lights. Use less. That costs nothing, but changing habits.

Then the next one is efficiency. Upgrading your insulation, upgrading your heating and cooling equipment, your window and so on.

And finally, the top of the pyramid is renewables. So once you’ve done the first two things, you can think about renewables. Renewables don’t really pay off until you’ve done conservation and efficiency.

Most of the gains are to be had in conservation and efficiency.

WW: And other trends”¦?

You’re starting to see—and the boomers are really leading it— the “smaller is better” trend. We are boomers and we don’t want a lot of space, [but] we want high quality space that’s comfortable, that’s easy to live in, that is energy efficient.

People want to be in a city or a town center, like Belfast or”¦ Port Clyde is not quite the town center [laughs], Portland. Munjoy Hill has enjoyed this tremendous resurgence because boomers want to be there and walk to the restaurants.

WW: So what advice would you give a young couple building a house today?

Thomas: Put your money into energy efficiency. Build small. It takes a lot of discipline to build small. Put your money into quality. You want to be able to lower your operating costs and maintenance costs.

There’s really three buckets of costs in a building. One is workmanship, one is materials and one is features. Workmanship you never want to compromise on. You don’t want to skimp on workmanship.

Materials are something you can play with. You want good quality materials, but a concrete floor is a high quality floor and a Carrara marble floor is a high quality floor but the two are vastly different in cost.

Features [are things like] a swimming pool, a sauna, crown molding, wainscoting. By eliminating features, you can lower cost.

I always tell younger people, “Beware of buying a lot of stuff,” because you spend 20 years acquiring it and then you reach the age of 55 or so and then spend five years getting rid of it all. Why bother acquiring it to begin with?

WW: Let’s talk about Habitat for Humanity. You’re their national spokesman?

Thomas: I’ve followed Habitat for over 20 years, doing television. We did a story on “This Old House” on the Charlotte chapter of Habitat, then we did a two-part special on Carter’s work project in Winnipeg, Canada, and I continued to follow Habitat through my “This Old House” career. I did a five-part series for DIY on Habitat in 2003.

I’ve watched Habitat develop as an organization. It is the world’s largest housing NGO. It has worldwide reach. Its build methodology has gotten more and more sophisticated. Habitat, at last count, was the sixth largest builder in the U.S.

And every house being built in the U.S. by Habitat is being built to some green standard.

Habitat is a Christian housing ministry and the ethics of building an energy efficient house are very much foremost on Habitat’s mind. If you’re seeking to put somebody into the house for the first time—and by the way, they do buy that house, they have to qualify for the mortgage; they have to put in, typically, 500 hours of volunteer labor before they’re even in the queue for their own house—so if you’re going to put someone like that into a house for the first time, you want to make sure the operating costs are as low as possible.

So this is real work-force housing. As a kid, my dad had a series of $20,000, $25,000 houses. He’d fix them up, sell them, buy a little bigger one as the kids got more numerous.

In the big run-up in housing value in the ’80s and then ’90 and a little bit in the 2000s, it became harder and harder to get entry level housing.

That may change now, because as Gen Y starts to have the ability to have their own place to live, they don’t want big, they want small.

I had the opportunity three years ago to join Habitat full time. It’s something I’ve wanted to do for a long time. I have tremendous respect for Habitat. It is probably the most leveraged that I can achieve in the world in terms of leaving the world a better place”¦ decent, simple housing, the profound way that can change the life of a family and therefore change the life of a community, is huge.