I think this is called a split system with the heat pump outside and an air handler w/ filter in the attic. It's a Carrier model that appears to be from 1996, my wife and I moved in in 2005. The model # is 38YKC024300

A large tree fell on the heat pump and smashed it. The HVAC folks who have come by for estimates tell me that it's not a good idea to replace the heat pump with an 2008 model without also replacing the 1996 air handler in the attic. It sounds reasonable but I'm not sure I can get the insurance company to agree. Any advice on if I should replace both Heat Pump and Air Handler? I'm trying not to waste money where I don't have to. For all I know the current Air Handler will last forever. What are the consequences if I just replace the heat pump unit that got smashed by the tree?

Thanks very much!