That being said, if you mainly want one for heat you would choose a floor model. It allows you the advantage of changing settings without having to go near the unit. If you have a floor model you may feel it is a waste of money, but if it is high on the wall, you really don't have a choice. There is a school of thought of The More Complicated the Better . Chances are something will go wrong.
Most models have an automatic breaker in case of fluctuation of power or a momentary outage.
Make sure that it will automatically go back on. Measure that it fits right . Not just the length and width, but the depth . Most of all keep your cool.