We’ve talked about energy-efficient windows in the past (as well as tips for maintaining your windows and their efficiency) and how they can save you money.

But how do you how efficient a window actually is? Thankfully, there are a handful of regulartory bodies that provide reliable statistics for researching how efficent and window is.

We found this great video (via Weather Shield Windows) that explains the different statistics you may run into while looking at windows. Watch it below: