Last fall, Jacob and Rissa Witul were living in California and considering a move to Boston or Washington, D.C. Then they received an e-mail from his Aunt Mary Witul of Kilbuck, bragging about the real estate bargains in Western Pennsylvania.

They were intrigued by photos of the former Ben Avon United Methodist Church, now converted into a 10,000-square-foot home. So intrigued that they flew here a week later to take a tour.

"Our friends thought we were crazy," says Mrs. Witul, 33, a promotions project manager for a brand-imaging provider. "They were like, 'What's in Pittsburgh?'"

"We couldn't send back a Primanti Bros. sandwich," adds Mr. Witul, 34, laughing.

Like those french fry-topped meals, the nearly century-old Tudor-Gothic-style church was too much of a treat to pass up. By Thanksgiving 2006, the couple had bought it and moved in. Today, it's one of six homes featured on the Ben Avon Holiday House Tour, which features "green" and sustainable construction and materials.

Recycling building components is a favorite earth-friendly technique, so what could be greener than giving a whole building a new use? The house's cool factor was certainly one attraction for the California couple, who quickly discovered that it was cool in the other sense of the word, too (old radiators struggle to maintain the temperature in the high-ceilinged space.

But what really wowed them was the price, about $600,000. That amount would buy a nice-but-hardly-spectacular home in Boston or D.C., says Mr. Witul, who does contract information technology work for Sysco Corp.

"And how many people own a church house?" asks Mrs. Witul. "It's unique."

The same could be said of the other houses on the Avon Club Foundation-sponsored tour. One of the first house tours in the region to hang its hat on sustainability, it features homes that model preservation -- another form of recycling -- and energy efficiency. A 1906 brick Colonial on Church Avenue, for instance, contains an artist's studio made entirely from cabinets and doors bought at Construction Junction and bookcases made from reclaimed molding and windows. A lovingly preserved and updated 1883 Victorian on Dickson Avenue boasts underfloor radiant heat. The tour also includes one of the country's original "prefab" homes: a Mission-style Sears "kit" home built in the 1920s.

"We felt if we educated people about green building principles, they'd find they can incorporate some environmentally responsible items into their own homes for little or no cost," says tour chairwoman Chris Cieslak, a green builder.

In keeping with that theme, programs were printed on recyclable paper and homeowners were encouraged to use green cleaning products and borrow holiday decor. In addition, says Mrs. Cieslak, the club purchased renewable energy credits, also known as green tags, from Bonneville Environmental Foundation to offset the conventional energy costs of the tour.

Speaking of energy costs, your brain can't help but start ca-chinging the gas and electric bills at the Wituls' church house. Yet it's the imaginative retooling of its clerical spaces that's the real mind-blower.

In 1993, the previous owners undertook its conversion, taking great care to retain the historical charm and character of the 1914 church, which was designed by Sewickley Heights native Thomas Barnes Wolfe (1860-1923) and built of Beaver County sandstone. For instance, all of the ecclesiastical brass door plates and knobs remain, along with its original floors and leaded- and stained-glass windows. They also repurposed a choir loft handrail into a brass railing in the kitchen and crafted an altar fixture into a dining room credenza.

Because the church's original footprint is essentially unchanged, the house features some pretty big spaces. Take the former nave, now a two-story great room. Absent the pews that once seated up to 300 worshippers, it's vast enough to hold an eat-in kitchen on one side, a full bar area on the other and in between, a large room living area with a free-standing gas fireplace. The former narthex, where countless brides took a deep breath before heading down the aisle, has been fashioned into a dining room. The room is so spacious that the couple's 10 1/2-foot blue spruce Christmas tree is practically dwarfed.

"Once in a while, we'll look around and then at each other and just be in awe," admits Mrs. Witul. "It's huge!"

Ditto with the recreation area in the basement, which during the tour will double as Santa's workshop. The ceilings are high enough to play basketball. And yes, they do occasionally cook on the 10-burner Vulcan range in the adjoining commercial kitchen.

"If I burn my hands, I'm probably still going to use words you wouldn't say in a church," jokes Mr. Witul.

The home's private spaces are much more intimate. The master bedroom, which is in the former choir loft, has privacy walls with diamond lattice that echoes the Gothic arched windows. Adding to the cozy feel is a gas fireplace and gold stars painted on the dark-blue ceiling. Downstairs, they installed a "bullet" wall in front of the stairs leading to the former chancel so the library area inside wouldn't feel so open, despite its 20-foot ceiling.

It might seem like a lot of space for just two people and their two dogs and a cat. But the Wituls couldn't be happier with their new home. The same goes for their new neighborhood. Within two months of moving in, Mrs. Witul says they'd met more neighbors than the entire time they lived in California. And this Halloween? Nearly 100 kids came trick-or-treating.

"I think we had a total of five or six in five years in California," she says, smiling. "So it was like, wow!"