Some winter months, Leandra Huante-Garcia and her husband, Jaime Huante, have paid $200 or more to heat the small, old, uninsulated rental house they share with their three children.

But in a month or so they will move from Ferndale into a new house in Bellingham where they might pay $200 - maybe even as little as $100 - to stay warm for an entire year.

Their house nearing completion at 2776 W. Indiana St. is being built by Habitat Humanity in Whatcom County. That's the local chapter of the Christian organization that uses donations, fundraising and sweat equity to build homes for needy families. Families help build their house and buy them with just $500 down and 0 percent interest on the mortgage.

The Indiana Street home is the 34th to be built by the local chapter. It's also the first here to use a "passive house" design to make it superefficient energywise, thanks to extra insulation inside extra-wide walls and other special construction methods.

"What's heating the house is the bodies of the occupants," said Marcus Swed, the Bellingham architect who designed the house. "It's about as efficient as you can get."

For Leandra Huante-Garcia, she's thrilled and grateful just to be moving into an affordable house that, with four bedrooms, is large enough for her family. The future savings on their energy bills make it that much sweeter.

"It's going to be very good for us in the future," she said. "It's a blessing; that's all I can say."

NEW DIRECTION

John Moon, executive director of the Habitat chapter, said all future Habitat houses built in the county will use so-called "passive design" to make the homes highly energy-efficient. Building such homes costs more - about $12,500 more for the Indiana Street house - but the lower heating costs outstrip the modest increase in mortgage payments - about $35 a month more for the Huantes.

"The payback is so remarkable," Moon said.

Only a handful of Habitat chapters across the country have built passive-design houses, he said, and the local project might be the first such Habitat effort west of the Rockies.

To cover the higher construction costs, the chapter will do more community fundraising, Moon said. For the Huantes' house for example, nine churches have donated money and/or volunteer labor: Acme Presbyterian, Birchwood Presbyterian, Cornwall Church, First Congregational, First Presbyterian, Lettered Streets Covenant, St. Paul's Episcopal, St. Sophia Greek Orthodox, and Oikos Fellowship.

To keep the house warm, the space between the exterior and inside walls is 12 inches, instead of the standard 6 inches. That provides more room for insulation. There's also extra insulation between the ceiling and the second floor.

In addition, the exterior walls are load-bearing, with minimal structural connections between the outside and inside walls. That way, less heat escapes through connecting studs.

The appliances and windows are energy-efficient, of course, and the house is snug with extra caulking, insulating boards below the concrete slab and the footings of the exterior walls, and extra framing and seals around the windows.

An air-to-air heat exchanger will use warm air leaving the house to heat cool outside air flowing in. Each room will have a small electric heater for backup, but they likely won't be used much, if at all.

LUCKY PHONE CALL

Leandra Huante-Garcia wasn't thinking about a new house when she first called the Habitat chapter. In fact, she didn't know they built houses. She thought the chapter provided household furnishings, and called to see if they might have carpeting.

Fortunately, the office worker who took her call asked some extra questions and suggested that the family apply to see if they might qualify for housing help.

"From there it just took off," Huante-Garcia said.

She has lived in Whatcom County all of her 29 years. Her husband, 38, has lived in the county about 25 years. He's a dairy milker and she holds two child-care jobs, at a church and at a gym.

They have two daughters, Alejandra, 9, and Guadalupe, 5, and one son, Jaime Jr., who will be 2 in April.

The two-story house sits on a small lot, one of four lots in Birchwood neighborhood owned by Kulshan Community Land Trust. The house is just 1,210 square feet, but it's a giant step up for the family.

"It looks so big to us," Leandra Huante-Garcia said. "To us, oh my gosh, it's like we won the Lotto."

MORE INFORMATION

What: Habitat for Humanity in Whatcom County

Address: 1385 Admiral Place, Ferndale, WA 98248

Coming up: The chapter's "Raise the Roof" annual benefit auction will be 5:30 p.m. May 16 at Hotel Bellwether. Tickets are $50.

Details: 360-715-9170, hfhwhatcom.org.

Reach DEAN KAHN at dean.kahn@bellinghamherald.com or call 715-2291.