Is the duvet covered by a guarantee? June 21, 2019 11:29 Follow Our mattresses come with a 10 year guarantee and everything else is covered for manufacturing defects for 1 year. Related articles Can I machine wash my duvet? Which way up do I use the Hybrid Duvet? Do I need to use a duvet cover? Didn't you sell a different duvet? Why did you change it? What is the duvet made of, will it keep me from over-heating?