There is now provided a polyisocyanate based rigid closed cell foam made by reacting an organic isocyanate with a polyol composition in the presence of a blowing agent, where the polyol composition contains at least: a) an aromatic amine initiated polyoxyalkylene polyether polyol having an hydroxyl number of 200 meq polyol/g KOH or more; b) an aliphatic amine initiated polyoxyalkylene polyether polyol having an hydroxyl number of 200 meq polyol/g KOH or more; and c) an aromatic polyester polyol having an hydroxyl number of 200 meq. polyol/g KOH or more. The blowing agent is selected from the group consisting of cyclopentane, HFC's, HCFC's, and mixtures thereof in an amount of 5.0 weight percent or more based on the weight of the polyol composition. Preferably, the blowing agent is soluble in the polyol composition without sacrificing, and advantageously improving, the thermal insulation and dimensional stability of the resulting polyurethane foam. Also disclosed are a storage stable polyol composition and methods for making a polyisocyanate based rigid closed cell foam.