You posted under Residential Energy codes. There are no minimum efficiency standards for equipment in CH 4. EPACT has covered minimum efficiencies for residential grade equipment and therefore one can't buy equipment that does not comply.
If you were referring to Commercial Mech equipment covered under Table 5, that is saying that IF certain equipment is installed, it must meet the tables under 503.2.3. Equipment outside the scope of those tables is not included in the scope of the IECC (solid fuel heating, variable refrigerant, heat recovery chillers, etc).
Note that electric resistance is always 100% efficient, so no efficiency standard apply anyway.