the recommendation I had read was the level of insulation and air tightness of your home should contribute to a heat loss level of 2 Watts/Kelvin/m2 before you should consider using a heat pump. But here building standards are pretty much non existent, and with flimsy poor quality windows/doors, persianas which essentially leaves holes in the wall, vents in the roof....working around those obstacles seems difficult as with finding trades people with knowledge/experience in this area. would be interest to hear how you managed this.i am going to give this a shot. i bought heat pumps for my na unit 14 years. i think they are toshiba. a heat pump run the freon in one direction for cool and reverses the direction for heat. it works well. you set your themostat to auto, set the temperature, it will keep your house at that temperature. its common in the desert. the option is to have a cooling system usually electric and a heat system using gas. hope this helps. its a brief explanation.