According to a market study by the Window and Door Manufacturers Association (WDMA), in 2013 the overall residential window market growth of 10% reached a total estimate of 44.5 million units shipped. Growth is expected to continue at a slightly slower pace for 2014 and 2015, forecasting 9.1% and 8.3% respectively. Residential entry door showed modest growth of 5.3% for 2013, with 14.1 million units shipped. Growth in residential entry door shipments is similarly expected to continue at a slightly slower pace for 2014 and 2015, forecasting 5.1% and 4.8% respectively. Read more.