IAPMO IGC-346 Test Method for Measuring the Performance of Drain Water Heat Recovery Units is now a published standard. This standard uses the same rules as the CSA standard B55.1 which was limited to evaluating the performance of vertical only drain water heat recovery units such as the ecodrain V1000. IGC 346 expands the scope to allow for testing of sloped units such as the ecodrain A1000 and B1000. It allows for the comparison of performance of units of different sizes and lengths. IGC-346 can serve as a parallel standard to CSA B55.1, and can be referenced in energy codes such as the IECC and the RESNET HERS Index. This is an important step in the advancement of drain water heat recovery as vertical systems are not applicable in many applications such as single story homes and showers on the first floor of homes without basements.