It was determined that there were not enough observations in the data received by Fannie Mae to adequately represent the national population of this size (fewer than 20 units). The survey included fewer than 10 properties in this size range. Given this limitation, EPA decided to exclude properties with less than 20 units from the sample set, which means the ENERGY STAR score will only apply to multifamily properties that are at least 20 units in size.
EPA performed additional analysis on data already in Portfolio Manager to further assess this question. Based on that analysis, it was determined that the smaller buildings do not have the same behavior – they exhibited a higher average score, with 60% earning scores of 75 of higher using the current methodology. Therefore, this analysis of data confirms that the ENERGY STAR score is not applicable below the 20-unit threshold.