A critical charge is the exact amount of refrigerant needed for a system to operate at its peak efficiency. In a Ductless Mini Split, even a few ounces too much or too little can cause major problems. This is why we insist on using a precise Refrigerant Scale during every installation. Our Multi-Zone systems are particularly sensitive to this charge. You can find the factory charge specs for all models in our Technical Data section. If your system has been repaired, a EPA 608 Certified tech must ensure the charge is correct to maintain your warranty. It is the key to achieving the high SEER2 Ratings advertised. Getting the charge right is a hallmark of a professional installation.