A. “Everyone does it the same way—with heat,” says John Curran, owner of Curran Glass Studio (6507 Ogden Ave., Berwyn, 708-795-8620; www.curranglass.com). Heat softens the glass, which is then molded into a curved form. Artisans at Curran do all this and more right in their shop; they are trained in restoration and specialty glass work.

It’s not necessarily a big deal to replace the glass. Ideally, you’d remove the sashes and bring them in to be worked on, but Curran understands that most people don’t want to live with boarded-up holes in their walls, so he is happy to send his experts out to measure your windows. They make the curved panes in the studio and come back to your house to install them. And they can fix up the wood sash a little, too, if it needs it. The whole process takes about two to four weeks, depending on how busy the shop is.

Beverly Glass Services (10430 S. Western Ave., 773-445-8211) is another excellent source, located as it is among the curved-windowed Victorian homes of Beverly. Its pros will come to your house to measure, noting whether you’ve got wood or metal frames and determining what thickness of glass you’ll need.

Beverly does not manufacture the glass in its shop; that job is sourced out to a distributor who also has the capability to temper bent glass. Tempering means heating the glass and then cooling it rapidly, a process that results in a safer piece of glass—if it breaks, it shatters into bead-like pieces rather than shards. According to manager Marci Terrones, standard sizes take about 14 workdays to manufacture and another two to five days to ship. Larger sizes can take four to six weeks.

Both Beverly and Curran Glass Studio can also supply you with small curved-glass replacement panes for your curio cabinet.

Lee Lumber (3250 N. Kedzie Ave., 773-509-6700; 633-643 W. Pershing Rd., 773-927-8282) sells bent-glass windows, too. Lee’s window people can either order them for you through Marvin, a big national brand, or make the sash in their shop and get the bent glass from their glass supplier. Which way to go? “If you have a landmark building and need to stick to strict guidelines, our shop can duplicate what you have,” says John Santana, sales representative at the Pershing Road store. Lee can make you a good old weight-and-pulley sash, whereas Marvin sells only sashes with sliding tracks. Also, if you need just one or two windows, it might be more efficient to have Lee do the work rather than to get windows from Marvin. But these are decisions Lee can help you make.

The costs for bent-glass windows range widely, depending on size, type of glass, whether the sash needs to be repaired or replaced, and difficulty of installation. Prices start as low as about $300 and go up into the thousands of dollars.