The number of residential window units shipped nationwide will rise 4.8% per year through 2017 and then slip 1.9% in 2018, the Window and Door Manufacturers Association (WDMA) announced today in its 2016 Window and Patio Door U.S. Market Study. This growth follows a 0.2% increase in 2015 that led to 57.36 million residential window units being shipped.

Sliding patio doors will see small increases in 2016 and 2017, 0.5% and 0.4%, respectively, before dipping 2.2% in 2018. This comes after an 8% increase in 2015. Hinged patio door shipments rose 0.9% in 2015. For this segment, WDMA's study forecasts a decrease of 9% in 2016 and 2017, and an 11% decrease in 2018.

The study, prepared by Hanley Wood's Metrostudy unit, relies on information about product shipments from 2015 and makes predictions about future growth. The WDMA's study is available for $2,500 here.