Best Replacement Windows of 2024

For our tests, we order 3×5-foot double-hung windows from a variety of manufacturers. Our previous window testing has shown that most windows stand up to simulated aging; we now focus instead on how well a window can withstand the elements.

After installing each window in a wooden frame, test engineers seal one side and rig a specially made device that simulates wind. They raise the airflow velocity to 25 mph and then 50 mph and measure air leakage with a flow meter. They run this test at 0° F and 70° F to evaluate whether the frames hold up even as materials contract and expand at varied temperatures.

To test rain resistance, we simulate windblown rain by pelting the window with 5 gallons of water per square foot per hour. Windows that earn an excellent rating in this test can withstand simulated winds up to 74 mph, or gale-force winds. The worst windows leaked at about 35 mph.

Another important takeaway: Our tests have found that even within the same brand of replacement windows, not all lines perform the same.