And being good at what it does is why not one of those windows reported any impact failure in the company's 27-year history.
That was in early 2005, six months after hurricanes Charley and Frances — the second- and third-most costly hurricanes in United States history at the time — hit Florida.
Prior to that Custom Window Systems was making its windows with aluminum, and they were non-impact (non-hurricane) windows.
"The large number of hurricanes that followed in 2005 (Dennis, Emily, Katrina, Rita and Wilma) confirmed our shift to vinyl," said Miller. "The switch also occurred because the vinyl frame material is much more energy-efficient."
Before the enormous plant, before the transition to vinyl, before the increased hurricane activity, Custom Windows was a small company started by John Cwik.
"The company started out making windows for porch enclosures, and it evolved over the years," Miller said. "There were a little over 50 people in the first couple of years of the company."
When the 44th Avenue plant opened there were 100 employees. Today there are 300, and Custom Windows needs to add 50 more to handle the company's growth.
Cwik sold the company last December.
Even when the housing market tanked in Florida, Miller said Custom Window Systems survived because of its forward thinking.
"Product development is the reason for our success and growth," Miller said. "There are always new products; we kept innovating."
Today the company's new products include a new line of French doors as well as high-design vinyl, impact-resistant products.
Window dealers and distributors are the company's primary customers. They in turn are seeing homeowners who are remodeling or replacing windows.
"We are almost to the point that we can't handle the growth," Miller said. "That is why we are hiring 50 new people."
It is a good problem to have.