The answer to 'mini split high energy bills' is that there are several common causes that can lead to high energy bills with a mini split HVAC system. These include poor insulation, refrigerant leaks, incorrect sizing, and inefficient compressors.
Poor insulation around the indoor and outdoor units can cause the system to work harder to maintain the desired temperature, leading to higher energy usage. Refrigerant leaks reduce the system's efficiency, forcing it to run more to compensate. If the mini split was not properly sized for the space, it may have to run constantly to try to reach the set temperature, again resulting in higher energy bills. Finally, an old or inefficient compressor can consume more electricity to operate, driving up costs.