If you want to insulate the interior of the block, CMU insulation blocks are available matching the interior dimensions of the block.
The overall insulation of CMU is very low ranging from R-1.11 up to R-1.28 depending upon the thickness of the block (8”, 10”, 12”)
The R-Value of a block wall insulated with CMU insulation blocks is R-13.5 for 8”, R-19 for 10” and R-23.6 for 12” block.
CMU insulation blocks ship from locations throught the United States and Canada.
Since there can be a slight difference in core size between CMU manufacturers, Universal Foam Products provides a sample, at no cost, to verify fit before the production order is run.