On amazon in the US you can get either a 12,000 btu through-the-wall AC unit for about $700 or a 12,000 btu wall ductless mini-split(heat pump, so AC and heat) for about $850. For either of those you can find models for cheaper or more expensive. I just chose general middle of the road prices. So the cost is no longer 5x, the prices are becoming a lot more comparable for heat pumps vs regular ac units. Also, if you check out the efficiency ratings, for most mini-splits these days, you'll make up the cost difference in your electrical bill vs a run of the mill AC unit in the medium to long run.