So when the windows started showing their age, the congregation took steps to save the 106-year-old treasures.
In December, workers from Hayloft Stained Glass of Shelburne Falls took the two most historically significant windows to be restored. This week, Hayloft workers are returning the windows to their places in the center of the sanctuary.
The 10 windows were the brainchild of key Chatham historical figure Marcellus Eldredge and his wife, Mary, who were not only instrumental in building the church in 1849, but the town library across the street as well.
The couple paid for the windows and commissioned Boston stained-glass artist Redding Baird to create them.
Neither lived to see the windows installed, but their niece, Mary, completed the project after their death and dedicated the two centerpiece portrait windows in the sanctuary - one of the Madonna and child, and the other of Joseph - in their memory.
Last year, the church's 300 or so parishioners came up with $39,000 to restore those two windows, according to Charles Hathaway, chairman of the church's board of trustees.
Yesterday, with a stiff ocean breeze blowing toward the church, the Madonna window was reinstalled by Hayloft owner Craig Colombero and craftsman Joseph Tracy. By tomorrow, both windows will be back in place.
Redding Baird imitated the style created by Louis Comfort Tiffany, which was to create the painting with the pieces of glass themselves, rather than by painting on the glass, Tracy said.
Unique to the two Chatham windows is the use of "drapery glass," which was created by pouring the molten glass into a kiln to create the undulating effect of the Madonna's and Joseph's garments, he said.
While some of the jewel-toned colors of the glass have faded a bit over the years, the colors have retained much of their vibrancy, Tracy said. The glass, for the most part, has also stood the test of time.
The leading around the glass was another story. It had deteriorated and was threatening to buckle the windows, he said.
Craftsmen at the turn of the century thought pure lead was the way to go with stained-glass windows, but an alloyed, or mixture of lead with other metals, later proved more durable, he said.
As a result, many windows created about 100 years ago are now in need of repair, including the ones at the Chatham church, Tracy said.
Hayloft craftsmen releaded the glass and replaced some small pieces of broken glass.
On the outside of the windows, they put up a protective plastic material, with vents to allow for the exchange of air and moisture.