Heat Pump AC unit replacement

[Christopher Stewart]

I've got a 3100 foot SFH rental with two different Heat Pump AC units, I think a 3 and 4 ton units. One of the units is about 15 years old and now needs a 1200 repair. The other unit is working but it's 25 years old and I'm told by the AC tech that the air handler blower motor and assembly is starting to fail and will cost 2500$ to repair. So I'm already starting to consider impounding some money to save up for just replacing the whole unit. There are different price ranges for replacement of heat pump split units that range from 5k-12k. Of course the more you pay the more efficient the units are. Since I am not paying for utilities on the rental, is there any reason to replace with a higher efficiency unit. I can't imagine that's going to be a big enough selling point for a renter to justify the higher cost?