R-1234ze: Pros, Cons & Comparisons to R-134a

Posted by Super Radiator Coils on Mar 26, 2021 8:59:30 AM

Our Refrigerant Focus series delves into the history, properties, suitable applications, and pros and cons of some of today’s popular or otherwise noteworthy refrigerants. This installment will focus on R-1234ze.

Check out some of our refrigerant focus posts below.


R-1234ze (scientific name 1,3,3,3-tetrafluoropropene) is known as a “next-gen” refrigerant. Next-gen refrigerants are a group of substances that includes refrigerants like R-32 and R-1234ze’s HFO brother, R-1234yf. These refrigerants all share a common trait: a fractional global warming potential (GWP) than that of their synthetic predecessors.

Most next-gen refrigerants, including R-1234ze, were developed to be long-term, sustainable replacements for environmentally harmful substances that are being regulated out of production. R-1234ze was developed and patented by Honeywell and designed as a replacement for R-134a.

Properties of R-1234ze

R-1234ze is classified as a hydrofluoroolefin (HFO), which is a class of unsaturated organic compounds made from a combination of hydrogen, carbon, and fluorine. The most notable property of R-1234ze – and HFOs more broadly – is their extremely low impact on the environment.

R-1234ze properties vs. r-134a-2

With a GWP somewhere between two and ten, R-1234ze is of significant interest to the engineering and scientific community for its potential as a low-GWP refrigerant. For a performance comparison, we’ve run a theoretical 36” x 70” 2-row condenser through our coil selection software, Enterprise. The coil’s airside and tube-side requirements are below and the coil’s rating is below that. We’ve included a rating for the same coil running R-134a as well.


ref. focus chat

It should also be noted that R-1234ze is not miscible with mineral oil. Ester-based synthetic lubricant will need to be used in compressors.

Applications for R-1234ze

R-1234ze: Pros

  • Low GWP: The primary benefit of R-1234ze is its low GWP and the resulting compliance with the latest environmental regulations.
  • Less refrigerant required: As illustrated in the above table, an R-1234ze condenser coil requires about 9% less refrigerant than an R-134a coil at the rated condition. 

R-1234ze: Cons

  • Lower thermal capacity than R-134a: R-134a is able to absorb and release more heat than R-1234ze. 
  • ASHRAE classification of A2L: R-1234ze is classified by ASHRAE as somewhat flammable. It can therefore not be retrofitted to R-134s systems, although R-1234ze’s flammability relative to other A2L substances is less black and white.

Honeywell claims that for R-1234ze to become flammable, it would need “10 times more concentration and 250,000 times more energy” than a hydrocarbon refrigerant. And even that couldn’t occur at temperatures lower than 86°F (30°C). This trait has led ASTM International to classify R-1234ze as non-flammable in the context of handling or storage.

Are you considering R-1234ze for your equipment? Give us a call if you have any questions on performance or register for our selection software, Enterprise and select R-1234ze as your refrigerant. From there, you can iterate on design conditions, materials, and more to find what best meets the needs of your requirement.

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