Yes, you can use a duvet cover with a cooling comforter, although some, like the Rest EverCool and the Coop Sleep goods Cool+ lack loops to easily attach a cover and are designed to be used on their own. Designs that are strictly inserts, like Cozy Earth, Lands' End or Silk & Snow, using a duvet for protection is highly recommended. Each comforter is designed to maintain its cooling benefits even when paired with a duvet cover, but choosing a duvet made with breathable cooling materials like cotton, linen, or bamboo can also enhance comfort.

While some cooling comforters are machine washable, others are more delicate and require dry cleaning or spot cleaning only. To ensure the maintenance of their cooling properties, it's important to check the care instructions for specific guidance on washing and drying. 

Dr. Winter recommends that in addition to ideal room temperature and light clothes, a cooling comforter that effectively dissipates heat can help hot sleepers achieve optimal sleep. The top cooling comforters incorporate advanced cooling technologies, along with materials like cotton, eucalyptus, and bamboo, which Dr. Dimitriu identifies as the coolest and most effective for dispersing heat and enhancing ventilation.