My husband and I have a relatively new heating unit but we kept our outside a/c unit. Now our AC bills and through the roof as well as the propane costs :( . We are curious if you can convert our existing heating unit to a heat pump for better energy savings.

Yes you can but it is costly, the outdoor unit and indoor evaporator coil would need to be replaced and maybe the thermostat, Good luck, Mike

Its not a conversion,, you add a heat pump to your existing furnace,, with a new coil .and tstat ,it replaces your outside a/c unit

If you have a system that is 3 to 4 years old the evaporator coil may work with a heat pump already. The system I think your asking about is called a dual fuel system. The heat pump will heat your home when the out side temp is 30 degrees and higher . And the furnace will heat your home when the out side temp is 29 degrees and below. It may be as easy as replacing your out side A/C with a heat pump and adding a dual fuel thermostat.