16 CFR 460.22: R-value claims for non-insulation products.

If you make an R-value claim for a product, other than a fenestration-related product, that is not home insulation and is marketed in whole or in part to reduce residential energy use by slowing heat flow, you must test the product pursuant to § 460.5 using a test or tests in that section appropriate to the product. Any advertised R-value claims must fairly reflect the results of those tests. For the purposes of this section, fenestration-related products include windows, doors, and skylights as well as attachments for those products.