This is an easy one. Despite their reputation for inducing sneezing, you’re actually less likely to experience allergy symptoms with a well-made down duvet versus a polyester duvet. This is because down duvets are more likely to have a tightly woven ticking or duvet case than a polyester duvet. The ‘down-proof’ encasement is meant to stop feathers poking through and to keep tiny down clusters inside the duvet. This makes your duvet both more durable and less likely to harbor dust mites as they can’t get through the tight weave. In contrast, polyester duvets tend to collect and retain heat and moisture and have more open encasements. This creates ideal conditions for breeding dust mites. Whether you have a dust mite allergy or not, look for the NOMITE logo when buying a duvet. This shows that the ticking is tight enough to act as a barrier to dust mites.