Columbia Sportswear Omni Heat fabrics can be found in jackets, hats, and other items. This specially designed fabric was created to reflect your own heat back to you before it is lost so the warmer that you are, the more heat you will have reflected back. According to studies during the development of this technology, Omni Heat may increase the warmth felt by a wearer to some degree. The study was not done beyond product testing so the results may not be perfect from the scientific standpoint. In general though, yes, Omni Heat will keep you warm. First, it's a coat/jacket so you are going to derive some heat from it. The reflected heat you feel will also help increase comfort especially if you are prone to being warmer than others around you.