Which Refrigerants are Allowed? Most manufacturers are adopting R-454B or R-32 refrigerants to comply with the regulations. These are commonly referred to as A2L refrigerants, referencing their low flammability. In the future, other refrigerants meeting the maximum 700 GWP rating may be used.

Disadvantages. The primary disadvantage of mini-splits is their cost. Such systems cost about $1,500 to $2,000 per ton (12,000 Btu per hour) of cooling capacity. This is about 30% more than central systems (not including ductwork) and may cost twice as much as window units of similar capacity.

DIY mini splits come with the refrigerant line already charged and do not require a professional to charge them. These DIY ductless mini split systems are designed to adjust the temperature in just one room, not over a large area of square footage.