Heat Pump Units Dimensions Space and Airflow Requirement Unit Dimension for WNZ08, WNZ12, WNZ12-3with 1” Male Inlets x 2 Unit Dimension for WNZ16, WNZ16-3with 1-1/4” Male Inlets x 2 Unit Dimension for WNZ20, WNZ20-3, WNZ26-3with 1-1/2” Male Inlets x 2 Unit Dimension for WNZ09-290with 1” Female Inlets x 2 Unit Dimension for WNZ15-290, WNZ15-290-3with 1” Female Inlets x 2 Unit Dimension for WNZ22-290, WNZ22-290-3 with 1-1/4” Female Inlets x 2 Heat Pump Specs