In construction, hollow-core concrete blocks (HCBs) offer a number of advantages over solid blocks, such as lighter weight and improved thermal and acoustic insulation. However, the relative high value of the overall heat transfer coefficient (U-value), makes them less attractive for use in new buildings in Europe, given that these must approach the net-zero energy performance level by 2020. In this respect, a project has been developed in Malta, which aims at producing a new HCB having the same physical dimensions and load bearing characteristics as a standard locally-produced HCB, but with improved thermal properties. The project (ThermHCB) is being co-financed by the Malta Council for Science and Technology (MCST) under the 2012 R&I National Programme. ThermHCB project is divided into a number of Work Packages covering the whole process from developing the HCB, manufacturing, testing and optimizing the final commercial product. This paper focuses on one aspect of this project, namely on the testing methodologies that are being proposed and implemented, for the load bearing as well as thermal characterization of the HCBs. In the latter, two procedures are being adopted to compare the thermal properties of standard and prototype HCBs, using infra-red techniques and heat flow methodology. Comparisons shall be made to verify whether the infra-red method, which offers faster measurement techniques, provides U-value results that are sufficiently accurate.