Provide decent sheets, together with blankets and winter quilts for sleeping in the bed (not at all those useless duvets). I make the effort in my house of sleeping without any kind of heating in winter, and that can only be done using several layers in the bed to sleep in. It is unbelievable that while I do that, a hotel in Norway in November does not, and obliges to use heating not to be cold: you ask for blankets and they don't have at all! Use clothes for that! Not energy! This policy is completely against the environment!