The Knauf Earthwool wall insulation batts start at an R-value of 1.5 and are the minimum value you can install. Installing thermal insulation such as the Earthwool R1.5 wall batts can improve the transfer of heat in your home and is best installed at the beginning of your build. Earthwool Wall batts will absorb the transfer of unwanted sound from outside to the inside of your building. The wall batts will improve the thermal comfort and energy efficiency of the building it is installed in, thus helping reduce the cost of your energy bill.