The invention relates to a polyether ester polyol comprising the conversion product of a1) of 5 to 63% by weight of one or more polyols or polyamines or mixtures thereof having an average functionality of 2.5 to 8, a2 ) from 2 to 50% by weight of one or more fatty acids, monoesters of fatty acids or mixtures thereof, and a3) from 35 to 70% by weight of one or more alkylene oxides of 2 to 4 carbon atoms.