I don't believe they are. There is apparently only one model in the Mirage lineup that is inverter, but the combination of Inverter plus Heat Pump design is not available. Mirage is the only Mexican manufacturer of A/C units, and import duties are so dear that foreign units become prohibitively expensive.

The SEER of the model I am getting (900 Xeries) is 10.3, not extraordinarily high, but adequate to my [hopefully] minimal needs. The SEER of the one model I know to be inverter (the "Magnum") is claimed to be 21, which I find difficult to believe. There are some subtle qualifications to that claim: It is only the 12K BTU model, it uses R410 coolant, and the SEER is "...up to 21" which suggests that only at the minimum speed is it that efficient. However, that model is disqualified because it has cooling only, no heating.

tanstaafl.