With laminate& floating floors, it's key to have both the underlayment fabric/lining, AND an extra soundproof layer as well. If you skip the 2nd layer, you'll regret each time a guest wearing heels,clack clacks across the surface. It sounds really cheesy if you don't.

Pergo is a well known brand name in flooring. As to the claims, you will have to request the documentation (read: you want to see their research paper) that states this if you REALLY want to know.

I've read the acoustic ratings for some of Pergos laminates. Without underlay the Pergo INCREASES the sound in an area! Fascinating...yet highly annoying. If this is a "cold weather refuge" (which I'm guessing means you want it to be "warm and cozy") then laminate is not one of the better choices. Laminate is not as cold as tiles...but it is no where near as warm as wood. Even an engineered hardwood is warmer than laminate. And warmer and quieter still is cork...but I'm trying to be objective here ;-)

To combat the acoustic problem and the thermal loss problem, you can expect to work with underlay (as kcjarret points out) that is a wool/fibre base product. This can cost as much as $2/sf. A cork underlay + vapour barrier (if you are over slab) can reduce that to $1/sf (1/4" cork underlay). It would act as your acoustic insulator and your thermal insulator.