About 4 yrs ago I bought a waterfront house in nc it gets about 90-95 degrees in the summer and in winter it has never gotten below 15 degrees,house is 2000sq ft, the current ac/furnace is about 8yrs old it is a goodman; I wanted to replace the ac unit with a 3 and 1/2 ton heat pump and reuse my air handler and possibly ciol and line set,mabe even keep the propane heat as opposed to elec strip.How much more efficient is a 13- or 14 seer unit as compared to a 15-16? Is it worth the extra 800 dollars? The new coils for the air handler look exactly like my current one do I need to replace it?I will be doing the work myself as I have installed a few systems myself{ac with gas } but never a heat pump yet, I am actually really drawn to the package type due to their simplicity and I could easily create some ductwok just need some input on reusing air handler/coil lineset etc thanks

There will be a period for any payback. The only true way to get a accurate pay back figure is to do a manual J on the structure then do a compairson of 13 against the 15=16 SEER unit. All else is bad guess work.

The coil should match the unit you decide to use Especially if a heat pump is being considered.