Thanks Bud, I am familiar with utility bills and costs here... but not how many hours a day a heat pump would have to be on in this climate.
I find your bill unusually high. It is about twice mine even though I have an electric stove/oven, 2 large fridges, and run 4 monitors for at least 12 hours a day. I had air conditioners running all the time in Panama City, so I know the cost, given A/C units are really just inflexible heat pumps.
In Canada, in an excessively insulated home, my electric bill (including heat and A/C) averaged $500/month with a lower per Kwh cost, with a high capacity heat pump, so I will worry about the cost after I find out whether the alternative is something that will do the job of providing greater comfort. My heat pump provided some heat as long as it was above zero F, but the difference in temperature between in and outside was often huge, so I was battling a lot of heat loss. I am less worried about the cost in Boquete because I am likely to try only for a 5 degree effect, especially because the large thermal mass of masonry homes here help keep the temperature from changing fast. I would guess that the compressor would run for short periods, mostly in the rainy season, although I might keep the fan on, possibly with a passive heat exchanger in the ducts to use in the cool periods.
I certainly am curious about the cost of operation (and installation, which is the biggest hurdle), which is why I need to find people who have tried using the heat pump in a climate like this, to get an idea of how much the heat pump would actually run and use power to run the compressor.