It’s amazing, the good things happening behind the scenes in Waterville.

Thursday morning, I stepped into a large community space at Children’s Discovery Museum off Eustis Parkway where a slew of volunteers was assembling energy efficient, insulating window inserts for homes.

The effort was headed up by a nonprofit organization called WindowDressers, which seeks to help people in Maine and across New England reduce heating costs, fossil fuel consumption and carbon dioxide emissions by lowering heat loss from windows.

Volunteers were working at several stations, installing tape around frames, cutting see-through plastic material and adhering it to the frames, shrink wrapping them and applying weather foam seal.

John Gardner, a retired mechanical engineer who specializes in energy efficiency, is local regional coordinator for the “community build” event. He said some of the volunteers Thursday were buying inserts for their own homes. The cost is about $50 per window insert, he said, but those who can’t afford that cost are eligible to get them at a reduced cost, or free, thanks to a grant from the Bill & Joan Alfond Foundation.

People applied for the inserts by going to the website, windowdressers.org. Gardner then visited their homes to measure windows and make sure they are appropriate for inserts. A factory in Searsmont cut the pine wood for the frames and Gardner picked it up Monday and brought it to Waterville where on Tuesday, he and volunteers built the frames. The project will take about six days.

Those receiving windows must volunteer, either by helping to build the inserts or doing another activity, such as cooking a meal for volunteers.

Pat O’Keefe of Winslow was volunteering Thursday because she ordered 14 window inserts, for a cost of about $1,000. She cooked a meal for volunteers Wednesday as part of her involvement, but then tried helping with the insert work and enjoyed it so much she couldn’t wait to return Thursday, she said.

“I’m building them — I’m all excited about it,” O’Keefe said. “I’m a community person and this is right up my alley, helping people.”

Chuck Lakin, a woodworker from Waterville, has been volunteering with the work since 2015 after learning about it from volunteer Peter Garrett of Winslow. Lakin built all the jigs at each station to help keep materials in place or move them along as workers assemble the inserts.

Lakin said they are easily installed windows as cold weather approaches and easily removable in spring, although some people keep them in year-round. He recalled that a woman who took part in a previous community build got inserts for her drafty windows and reported back that, not only were the drafts eliminated, but her heating bill was cut in half.

WindowDressers has built more than 68,000 inserts since 2010. The organization started out small in Rockland, but last year, more than 10,000 inserts were built at 50 community events in Vermont and Maine and one or two in New Hampshire, according to Lakin, who praised the nonprofit for its extraordinary work.

“It’s one of the reasons I stick around,” he said.

Gardner, who formerly taught mechanical engineering and, like Lakin, learned about WindowDressers from Garrett, said the event this year covers Waterville, Winslow and Vassalboro and more than 240 inserts are being built.

“Over 30 community builds are going on around the region,” he said.

Gardner lives in Oakland and is a member of the board of directors for Kennebec Messalonskee Trails along with his wife, Barbara Bowling, who is president of  that organization. He said the number of events launched each year to create window inserts depends on the availability of volunteers and the number of people wanting them. Last year, 190 inserts were created for people in Waterville alone.

Organizations such as the Waterville Rotary Club, Kennebec Valley Community Action Program heating assistant program help support the effort. Anyone interested in volunteering, or who may have questions, may email Gardner at [email protected], he said.

Caitlin Walker, program director for the Children’s Discovery Museum, said WindowDressers donated to the museum for use of the space and last year the museum received window inserts as part of the deal.

Volunteer Malcolm Campbell, a retired biology professor who moved from North Carolina to Oakland recently, was using a heat gun Thursday to help shrink the plastic film and tighten it on frames.

“It’s fun and it’s a good cause,” Campbell said. “It saves people money. It reduces the carbon footprint. For me, it’s part of community building. The quality is so good — it’s just like having glass.”