Fixed-bed regenerators (FBRs) are air-to-air energy exchangers (AAEEs) used to reduce energy consumption in heating, ventilation, and air conditioning (HVAC) systems. Since energy savings are directly related to the effectiveness of FBRs, testing is essential to determine the effectiveness of FBRs for quality assurances and during product development. However, testing of full-scale FBRs has disadvantages such as requiring full-scale prototypes, a high volume of conditioned airflow, long tests, and large testing laboratories. The disadvantages are especially crucial during product development and can be overcome by small-scale testing provided the test data can be used to evaluate accurately full-scale FBRs. The major contribution of this paper is two new methodologies (one direct method and one predictive method) to determine the sensible effectiveness of full-scale FBRs from small-scale test data. In the direct method, the effectiveness of the full-scale FBR is determined directly from the small-scale test data, whereas in the predictive method the effectiveness is determined using the Wilson plot technique and a numerical model in addition to the small-scale test data. Both methods are shown to have uncertainties within the specified uncertainty limits required by testing standards and are applied to evaluate the influence of geometrical parameters (corrugation angle and corrugation depth) on the effectiveness of FBRs. The test methods and results will be useful in the design and development of FBRs for HVAC applications.