The present invention relates to foam products made with blowing agent compositions comprising at least one hydrochlorofluoroolefin (HCFO) used in the preparation of foamable thermoplastic compositions. The HCFOs of the present invention include, but are not limited to, 1-chloro-3,3,3-trifluoropropene (HCFO-1233zd), particularly the trans-isomer, 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf), dichloro-fluorinated propenes, and mixtures thereof. The blowing agent compositions of the present invention are used with coblowing agents including carbon dioxide, atmospheric gases, hydrofluorocarbons (HFC), hydrofluoroolefins (HFO), alkanes, hydrofluoroethers (HFE), and mixtures thereof. Preferred HFCs used as coblowing agents in the present invention include, but are not limited too, 1,1,1,2-tetrafluoroethane (HFC-134a), 1,1-difluoroethane (HFC-152a), 1,1,1-trifluoroethane (HFC-143a), pentafluorethane (HFC-125), difluoromethane (HFC-32). The blowing agent compositions are useful in the production of low density insulating foams with improved k-factor.