Our Legacy packaged rooftop heat pump, the548J is available in 3 to 25 ton models that are ASHRAE 90.1 energy compliant.. These units offer a full line of factory options or field-installed accessories to go with 13.4 SEER cooling efficiency and 7.7 HSPF heating. Single- and multi-stage cooling and heating models are available with a variety of heating sizes for each unit size.