If that's the only room you want to cool I'd go with a room air conditioner.

Heat pumps are not efficient in temps below 40 or above around 80 with humidity. I would go with room AC unit.

A couple article excerpts and maybe family experience in Texas and North Carolina. My sister in North Carolina had trouble when outside temp was over 80.

There's no effective difference between a "heat pump" and an "air conditioner" regards to cooling. Air conditioners *are* heat pumps ... they pump heat from inside the space to outside. They just don't have a reversing valve to reverse the refrigeration process for moving heat the other direction, from outside to inside.

My heat pump can easily maintain 69°F or 70°F room temp at outdoor temps of 40°F, 35°F, 30°F, 25°F (winter temps rarely get lower than 25°F in my area of TX). Likewise, perfectly comfortable in summer season of +95°F.

"Heat pumps are not efficient in temps below 40 or above around 80 with humidity."

I don't know who's been feeding you this but heat pumps work just fine below 40 degrees and above 80 degrees (with or without humidity. Their efficiency is decreased as you go below 20 degrees but this is what supplementary heat is for, and in extremely humid conditions, their sensible cooling capcity is reduced (for latents cooling capacity) but they still work just fine and reduce indoor humidity in the process.

Don't believe everything you read!

Please don't tell my heat pump it isn't supposed to be working below 40 or above 80.

This is a reasonably good explanation. He says at the beginning "A heat pump is a regular [looking] air conditioner with some extra parts in it. The difference between an air conditioner and a heat pump is that a straight air conditioner uses refrigerant to take heat out of the house and bring it outside, whereas a heat pump, it can reverse the flow of refrigerant which causes it to take the heat from outside and bring it inside."

There have been heat pump window units on the market since the 1950s, perhaps earlier. Friedrich was known for their TwinTemp line which had electric resistance and reverse-cycle heat pump models. We had a Whirlpool at work with both electric resistance and reverse-cycle heat pump, it had a outside thermostat that automatically switched the heating mode according to the outdoor temperature.