A factor in considering this is will the single zone coil provide even heat in the required area. In point of fact, will a dual zone accomplish this.
It is effectively a window installed heater. Can you heat or cool what needs to be conditioned from such a unit without other air circulation. If no, and you do not have such an air circulation system, you have a problem. Since heat pumps tend to have low "warm air" temperatures to start with, this could be problematic.