Duvet cover system having customizable variable performance

A duvet cover system for covering a bed, the system comprising:

• a cover layer configured to receive a fill layer in the form of a blanket or comforter, the cover layer also being configured to at least substantially enclose the fill layer and provide a desired aesthetic appearance to the duvet cover system;
• and
• a duvet insert defining the fill layer, the duvet insert including a first insert portion including a plurality of first quilt boxes defined by a first cover fabric, and a second insert portion including a plurality of second quilt boxes defined by a second cover fabric, the first and second insert portions being positioned such that the first insert portion covers a first side of the bed and the second insert portion covers a second side of the bed when the duvet cover system is assembled and spread over the bed,
• wherein the plurality of first quilt boxes are filled with a first fill material having a first fill volume to thereby define at least two quantifiable performance factors for the first insert portion, including a first thermal retention value and a first air permeability value, the plurality of second quilt boxes are filled with a second fill material having a second fill volume to thereby define at least two quantifiable performance factors for the second insert portion, including a second thermal retention value and a second air permeability value, and the quantifiable performance factors of the first and second insert portions are different from each other to provide different sleep experiences for users located on first and second sides of the bed under the duvet cover system.