The interior of the house is about 125 square feet, which is 90 percent smaller than their current home in Boulder, Colo., Christopher Smith and Merete Mueller said.
The new house has many features based in sustainability, including reclaimed windows, beetle-kill lumber, solar power and a composting toilet filled with peat moss and sawdust, KMGH-TV, Denver, reported Wednesday.
"When we set out it was to show that a normal person, who never built anything before, can take on a project like this and finish it," Smith said. The construction was filmed for a documentary called "Tiny" that explores "the ways we find ourselves at home," the couple's Web site said.
Smith and Mueller said the project was originally going to function as a second home, but they are now considering making it their full-time residence.
"The more that I've been working on it with Merete, and the more we visit other people's tiny houses, it's starting to feel more and more like a home, and I can definitely picture myself living in it full-time," Smith said.
Celebrity Couples of 2014 [PHOTOS]