You have a CHOICE of Two Identical CARS - One gets 10 mpg (28 L/100 km)
One gets 40 mpg (07 L/100 km)
If you Park them both in the Driveway
they will Both Perform Exactly the Same.
Likewise Windows. They LOOK Identical. One Saves 10% of Energy One Saves 40%
If you Put them in the Basement and cover them with a Blanket
they will both Perform Exactly the Same!
However, If You put them on the Envelope of your Home,
they are either putting money IN your pocket or taking Money Out of Your Pocket...
every month, month-in, month-out for decades.
And at an Ever-Increasing Rate!
That's just BANANAS
When You Compare Windows... Make Sure It's Apples-to-Apples