Sentence meaning - a waste of
Solution 1:
Loose covers are fitted covers for upholstered armchairs, to protect the upholstery or hide it when it is worn out. I think the author is using waste in the sense of area of barren land (see https://en.oxforddictionaries.com/definition/waste , noun definition 3). A snowy waste is a large area of empty land covered in snow, and the room is seen as an unprofitable area covered in cretonne (furnishing fabric).