A fan includes an outer casing having an air inlet and an air outlet, and an impeller housing located within the casing. An impeller is provided within the impeller housing for generating an air flow along a path extending from the air inlet to the air outlet through the impeller housing. A motor for driving the impeller is located within a motor housing connected to the impeller housing. A foam annular seal is located between the impeller housing and a seat to inhibit the leakage of air between the impeller housing and the casing. A plurality of resilient supports is provided between the impeller housing and the seat to reduce the load on the annular seal.