Shay Gibbons, 57, said it started with a simple Christmas party in 1984.
"I did more decorating because of the party," she told ABC News in an interview for " 20/20." "Every year it just gets a little bigger. … Now it's just big."
With 169 Christmas trees, 100 nativity scenes, dozens of inflatable yard characters, 50,000 ornaments and 100,000 lights covering their Tulsa, Okla. home, Gibbons' husband, Tom Gibbons, agreed - big is an understatement.
"It kind of became a sickness," Shay Gibbons' daughter Charity McGuire said. "A contagious sickness."
Watch the full story on "20/20: Holidays Unplugged" Friday at 10 p.m. ET
McGuire, 35, grew up with the tradition and fully commits to helping decorate. She said she's happy her mother's hobby brings joy to others and keeps her out of trouble.
"It's just fun," McGuire said. "If it wasn't this, she'd find something else, and this is safe."
Starting Oct. 1, Shay Gibbons said, she pulls out her mountains of holiday décor from every storage attic and garage in her 3,200-square-foot home. Only 800 square feet of living space will be left uncovered when they finish this weekend.
Next week Gibbons will host a community party, where for the price of a donated toy for charity, her neighbors and friends can enjoy the handiwork - complete with a surprise tree in the most unlikely of places: her bathtub.
"There are people up and down our street all the time just looking," Shay Gibbons laughed. "They don't have any electric left. I've got all their electricity!"
Their electricity usage doubles during the Christmas season, they said.
"I've tried to run it by her, like, 'Do it every other year,'" he said. "But she supports me in what I love to do, so I love to support her."
There is another upside to life in a life-sized Christmas snow globe. With all those hot lights, the Gibbons never have to turn on the heat.
"You just turn on all the lights and it just makes you feel good," Shay Gibbons said. "You can't be sad in this house."
Watch a hilarious video above, and watch the full story on "20/20: Holidays Unplugged" Friday at 10 p.m. ET