Refrigerant Solutions Ltd (RSL) has developed RS-50 (R442A), a replacement for R404A, which has less than half the direct Global Warming Potential and higher energy efficiency. This new refrigerant has a safety classification from ASHRAE of A1, namely low toxicity and non flammable.
The current pressure on controlling & reducing HFCs is unlikely to diminish. Review of the F Gas regulation in Europe is not yet complete but a phase-down in the production and consumption of HFCs would not be unexpected. It is even possible that eventually HFCs will be taxed according to their GWP. R404A is at the high end of direct global warming for HFCs and is, therefore, vulnerable to early replacement provided a suitable alternative can be found. RS-50 is potentially such an alternative.

RS-50 can replace R404A in both new and existing installations. To replace R404A in existing equipment, very little needs to be done other than in some cases it may be necessary to adjust the expansion device by narrowing the opening since RS-50 has a lower mass flow rate than R404A (similar to R22).

Tests show that RS-50 is significantly more energy efficient than R404A which can realise substantive costs savings for users.

With the ban on the sale of recycled R22 fast approaching, RSL has available drop-in replacements making conversions away from R22 easier. RS-44 (R424A) replaces R22 in air conditioning, and RS-45 in refrigeration applications. RS-45 is the only suitable alternative to R22 in flooded systems where it has been operating successfully for several years.