According to the Federal Trade Commission, replacement window companies “must have scientific evidence before making marketing claims.” Apparently a lot of replacement window companies didn’t realize that lying is frowned upon.
Here’s a link to the FTC press release. One interesting point, even claiming “up to” x percentage of energy savings incurred the wrath of the FTC. This could have far-reaching implications for liars in other industries. In the United States, up to 99% of advertising contains weasel words.