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As chairman of the Alamo Sierra Club, local environmentalist and San Antonio native Alan Montemayor tries to walk the walk as he talks the talk.

Over the last 20 years, Montemayor and his wife Cheryl Hamilton have slowly evolved their Castle Hills home into a showcase of what San Antonio residents can do to live a greener lifestyle.

Montemayor and Hamilton, both retired — he from the Southwest Research Institute and she from special education and education administration — have chosen more sustainable options each time it came time to replace a feature of their home.

Over time, their house has evolved into a “net-zero” home, balancing the energy generated from its solar panels with the power needed to live in it.

Whether folks want to admit it or not, climate change is here, Montemayor said, pointing to Winter Storm Uri as a recent example of storms becoming more extreme.

A report released last fall by the Texas State Climatologist Office echoes Montemayor, predicting Texas will experience more severe floods, droughts, storms and wildfires as a result of climate change over the next century.

While tricking out one’s home to be more eco-friendly can be a costly endeavor likely difficult for most San Antonians to afford, small changes can add up, Montemayor said.

That can include switching to LED lights as traditional bulbs burn out, reusing items, recycling others and reducing waste overall, Hamilton said. Everything from using reusable grocery bags to sustainable water bottles is a choice, Montemayor added.

Those personal choices add up, Hamilton said, and she believes they will be critical to successfully fighting climate change.

“It has to be grassroots,” she said. “It has to be each household, each person because if we wait for the Texas state Legislature, or the governor or the City Council to make these decisions, it’s not going to happen.”

Montemayor agrees that individual actions are important, but also emphasizes that policy changes must play a role.

“We have to tackle this at all levels,” he said. “If we’re going to be successful, I mean, climate change is the 500-pound gorilla in the room, and if we’re going to tackle it successfully it’s going to take everyone working together.”

The couple invites between 50 to 200 visitors to their home twice a year to see the various technologies they’ve installed.

At first glance, the home appears similar to the others in the neighborhood. But quickly, details come into view that signal how different it actually is. Perhaps most noticeable are the solar panels on the recycled metal roof of the 1950s-era brick house.

“Before we put the solar panels on the house, we first made the house as efficient as possible,” Montemayor said. “That entailed redoing all the external doors and windows. The doors and windows are double-pane, argon-filled, low-E glass — all retrofit. We [replaced] all the bulbs with LEDs for low energy consumption and low heat generation inside the house in the summertime.”

The solar panels are sized to supply 115% of the household’s electric needs, including charging the couple’s two electric cars — with excess electricity going back onto the grid, Hamilton said. They generate an estimated 5,015 kilowatt-hours per year, she added.

The couple owns a 2014 Mitsubishi i-MiEV and a 2017 Chevrolet Bolt, which they use almost exclusively, even on long road trips to Big Bend National Park. Their level two electric car charger, which charges their cars more quickly than the more common level one charger, is a Texas rarity, they say, and the first residential one in town.

The front yard is mostly mulch, with native plants and other plotted areas scattered smartly across the lawn. Each plant species is neatly labeled with garden markers. A solar oven sits out front, silver doors open to the sky like wings, a small black pot inside. Oak trees have been allowed to grow large and low to the ground, giving shade to the home so heating and cooling systems aren’t needed as often.

Two large rain drums dominate the backyard, each of which can hold 1,600 gallons of rainwater. One inch of rain is equivalent to about 2,300 gallons, Hamilton said. The drums are attached to a rainwater sink, hose system and compost irrigator that the couple can use at their convenience.

“It’s a work in progress,” Montemayor said. “The next steps are we want to use a little bit of the rainwater to create a rainwater shower. We will have a solar heater on the rainwater so it’ll be nice and warm. And we want to take a little bit of [the rainwater] and spray it on the condenser unit of our air conditioner so the air conditioner will gain about a 5% increase in the cooling efficiency.”

The couple recognizes that not everyone has the ability, time or money to use rainwater to boost their air conditioner’s efficiency by 5%. But they hope the varied efforts they’ve taken will inspire others to do what they can.

“We like to think everybody can get a hold of the low-hanging fruit first,” Hamilton said.

Lindsey Carnett is the Science & Utilities reporter for the San Antonio Report. More by Lindsey Carnett