Neighbors driving by Barbara and Gary Gardner’s new house in Beaver County can’t tell it’s super energy-efficient and Passive House-certified. But they like the way it looks.

“I called a building supply company in Chippewa for concrete block to build a fire pit,” Mr. Gardner said.

When he gave his address, he heard a laugh on the other end.

“The new house? Oh that’s pretty. I live down the road,” the man said.

Drive-bys in Brighton can glimpse the house’s large windows, fiber cement siding, rain chains and ornamental grasses. But they can’t see the really pretty parts: 8½-foot ceilings, hickory floors and doors, granite counter tops and a sleek, funky Roman tub that doubles as a shower. People who have seen the inside give it rave reviews.

“They’re surprised by how much they like the aesthetics,” said Mr. Gardner, a retired architect who works as a consultant in sustainability and Passive House design.

Designers, contractors and other “green” professionals from around the world will get to tour the three-bedroom, two-bath house during the North American Passive House Network national conference Oct. 17-21 (https://naphnconference.com) at the David L. Lawrence Convention Center, Downtown. The Gardners enjoy being guinea pigs for Passive House, a rigorous standard for energy efficiency that results in low energy use and small utility bills (the Gardners pay an average of $100 a month). They have lived in three conventional houses in Western Pennsylvania — two in Mt. Lebanon and one in Edgewood — and say this is the most comfortable by far.

“The air is really fresh. I never feel like it’s too dry,” Mrs. Gardner said. “It’s a lot different comfort-wise than any other house.”

They set the thermostat at 68 degrees in winter, but they’re never cold. Mr. Gardener said that’s because comfort is about the surface temperature of walls and windows, not air temperature. Old house’s walls are generally colder than the air and drafty. These R-70 walls contain 5 inches of spray foam insulation and 6 inches of foam board; the roof packs nearly 18 inches of foam and board for an insulation value of R-74.

The thermostat is set at 76-78 degrees in summer and stays there due to 4-foot-deep overhangs and one 9,000-Btu air conditioner for its 2,400 square feet of living space. Compare that to the two 20,000-Btu units needed to air-condition their old 6,000-square-foot house in Mt. Lebanon.

In winter, the sun shining through triple-pane windows at a lower angle helps to passively heat the house, raising the interior temperature by 2 degrees on a sunny day. A small electric heat pump takes care of the rest.

Water is heated on demand for dish washing, showers or bathing their three grandchildren in the 14-inch-deep Roman tub. Mr. Gardner said it takes about 10 seconds for warm water to arrive via PEX plumbing, much less time than in their old houses.

“It’s like waiting for an elevator,” he said.

The house’s main storage space is the super-insulated attic and above the two-car detached garage. There is no basement because “every basement leaks,” Mr. Gardner said.

So why is the air so fresh in this super-tight house?

Credit the energy recovery ventilation unit that runs 24/7 in the attic. It works with a ground source heat loop that preheats filtered fresh air in the winter and precools it in the summer. A conventional house does a complete air change 5-7 times an hour. This house changes it once every two hours. Each room has three registers in the ceiling — a fresh air supply and return and one supply for heat or air conditioning.

This was the first Passive House for contractor Curtis Graf of Graf Custom Construction (www.grafcustomhomes.com). Construction cost was about $200 per square foot.

One of Mr. Gardner’s challenges was landscaping his 2-acre lot with something lower maintenance than a lawn. His solution was a grid of ornamental grasses in front, a paver patio, no-mow grass, wildflowers and a raised-bed vegetable garden in the back.

This year, the perennial wildflowers were mostly black-eyed Susans, but orange poppies and purple coneflowers will pop up next year in the deer-resistant meadow mix by Ernst.

Mr. Gardner keeps his plants hydrated with a rainwater harvesting system he designed. Rain chains hanging from the eaves carry water to underground pipes that feed a rain garden and a 600-gallon tank buried in the backyard.

“Wish I had made it bigger!” Mr. Gardner said.

It’s one of his few regrets. The treasurer for Passive House Western Pennsylvania (www.passivehousewpa.com) says sustainable construction is the only responsible alternative in a world where over 40 percent of global warming can be traced to buildings.

“You have to be committed,” he said. “You do this because you think it’s the right thing to do.”

Kevin Kirkland: kkirkland@post-gazette.com or 412-263-1978.

First Published: October 12, 2018, 12:00 p.m.