Alright, let’s talk R-407A. Selecting the proper refrigerant feels like selecting the best tool for a job – when it’s the wrong one, you waste time, energy, and money. You’re likely wondering: What is R-407A, and why should I give a hoot, and is it good or bad for my system, especially considering how there’s so much older stuff out there? Well, let’s unpack that — no corporate jargon, just sound reporting from the sources.

R-407A: What You Need to Know About This Key Refrigerant

So, what exactly is R-407A refrigerant? Simple. It is a blend of gases that are used in cooling systems. Think of it as a particular recipe — a mixture of three distinct refrigerants known as hydrofluorocarbons (HFCs): R-32 (difluoromethane), R-125 (pentafluoroethane) and R-134a (1,1,1,2-tetrafluoroethane). This isn’t a native chemical; it’s an expert mix designed to do a job.

Constituents and Important Characteristics of R-407A

Recipe for R-407A.Now let’s see how R-407A is made. It’s made up of:

• 20% R-32 (difluoromethane)
• 40% R-125 (pentafluoroethane)
• 40 vol.% R-134a (1,1,1,2-tetrafluoroethane)

Each part plays a role. The R-32 moderates heat capacity, the R-125 dials down flammability, and the R-134a prevents the overall pressure from rising into a danger zone.

But away from the blend, here are some need-to-know stats:

• Molecular weight: 90.1 g/mol.
• Boiling point: Approximately -49°F (-45°C).
• Critical temperature: Approximately 180°F (82.3°C).
• Critical pressure: Approximately 655 PSIG (45.1 Bars).
• ASHRAE Safety Group: A1. This makes it non-toxic and non-flammable and moves it into the higher security classification for refrigerants.
• ODP (Ozone Depletion Potential): 0. Some good news here — it doesn’t deplete the ozone layer, which older options, like R-22, do.
• GWP or Global Warming Potential: 2107. We’ll explore this more, but suffice it to say, this number is key in terms of environmental impact.

The Temperature Glide of R-407A explained

Now, there’s a technical term that you need to be familiar with when talking about R-407A: temperature glide. It’s a zeotropic mixture of chemicals, not a single chemical, and it goes by the name R-407A. This is because it boils and condenses slowly over a wide span of temperatures, not all at once at a steady temperature like some other refrigerants do.

The delta between where it starts to boil (bubble point) and where it finishes boiling (dew point) is the “glide”. For R-407A, the glide is approximately 8°F (-4.4°C). One reference says 6.4°C (11.5°F) at normal revs, another 8°F (-4.4°C). So, there should be a modest glide, say, around 8°F or a little more.

Consider distilling alcohol. There is glide in a mixture of water (b.p. 100°) and alcohol (b.p. 78°). When it is heated, the alcohol evaporates first, altering the composition of the mix as it is heated. That’s fractionation, and R-407A does it during phase change as well.

Why does this matter for you?

Charging: You have to charge R-407A as a liquid. Charging as a gas may also serve to fractionate different components, disrupting the blend’s intended composition and performance.

Pressure-Temperature Charts: The use of P-T charts requires an understanding of glide. Each temperature corresponds to a pair of pressures- bubble (liquid) and dew (vapor).

• You need that temperature to be the temperature at the evaporator inlet? Go with the bubble pressure.
• Want that temperature at the evaporator end when its the pure vapor? Use the dew pressure.
• When you work with an intermediate pressure, that’s the target temperature at which somewhere in the evaporator will freeze.
• Remember that P-T charts are frequently given as absolute pressure, so don’t forget to subtract atmospheric pressure (approximately 14.7 PSI) to get the gauge pressure that you will be reading on your manifold.

This glide complexity contrasts sharply with single-component refrigerants, especially when you are working on system design or servicing.

History and the Role as a Substitute Refrigerant

It was not the first refrigerant to arrive on the scene and nor was it the last proposed replacement. It’s like a “replacement replacement.”

Its history begins as a possible replacement to R-22 (Chlorodifluoromethane). R-22 dominated the market and it was phased out due to its ozone-depleting potential. R-407A was invented ind the same period as R-404A and R-507, at first to substitute R-502 in new medium and also low-temperature systems.

But R-404A (which replaced R-22 and R-502) went on for nearly 30 years in the supermarket sector, ­despite R-407A having a much lower GWP from the word go. By the time the compressor manufacturers had a good deal of time to test R-407A, R-404A was pretty well entrenched.

Fast forward, and the environmental regulations began to squeeze, particularly on high-GWP refrigerants such as R-404A (GWP ~3900). Suddenly, R-407A, with its much lower GWP (approximately 2100), seemed a lot more attractive. It began gaining traction as an alternative to dropping R-404A and as a compliance option for things like Europe’s F-Gas and similar regulations in the U.S. that banned virgin R-404A in servicing systems above a certain charge size.

So R-407A staked its early market claim largely as a retrofit solution, initially for R-22 and then critically as a lower-GWP option for systems designed for R-404A or R-507.

R-407A Performance Compared

In comparison to its predecessors, R-22 and R-404A, how does R-407A fare? Here’s what the sources say about how well it works, when compared with performance of a theoretically optimized coil design on the same input power:

For example a hypothetical evaporator coil in a refrigerated display case application.

Performance Comparison: R-404A vs. R-407A

What does this table tell us? If you were to replace R-404A with R-407A on this EXACT coil set-up, you may note:

• A slight capacity loss (appx 2.7%).
• Very slightly warmer discharge air (1.2°F).
• A much improved coil pressure drop (-44%). The lower the pressure drop, the less work that needs to be done by the compressor, which often equates to better efficiency.
• Refrigerant mass flow much lower (-31 %). This is because the system has to move less refrigerant per hour to get the job done, which can save over the long term.
• In general, you will get some efficiency by converting from R-404A to R-407A. A: R-407A needs lower refrigerant flow and has a lower coil pressure drop.

Performance Comparison: R-22 vs. R-407A

Comparing to R-22:

• Capacity is slightly better (1.6%) when using R-407A.
• Slightly cooler leaving air.
• An increased pressure drop across the coil (23%).
• More refrigerant mass flow (14%).
• R-407A behaves very much like R-22, especially in medium and low temp refrigeration with similar capacity and flow properties, so for retrofitting R-22 — look no further than R-407A. At low temperatures refrigeration capacity of R-407A was closers to R-22 than to R-404A or R-507, this source observes.

However, there’s a catch. Although it is more efficient than R-404A at medium temperatures, R-407A efficiency becomes greatly substantially low at about -20°F (-29°C). At such ultralow temperatures, an R-407A system could require 38 percent more compression power than an R-404A system in order to reach the same cooling target. So, super low temp wise, it may not be best. For medium temp (20F), the required compression ratio is still greater than R-404A (31%), but other improvements in efficiency can make up for that.

And best of all – it has a performance that ersembles R-22 and R-404A.

Applications of R-407A

Where does R-407A shine? Its natural habitat is medium to low temperature refrigeration. This includes:

• Supermarket refrigeration
• Food storage and processing
• Refrigerated display cases
• Marine transport
• Refrigerated transport

It is thought to be good for these purposes.

And importantly, it remains the leading choice to retrofit-and-replace current R-22 systems in these segments. Since its capacity and flow rates are very similar to R-22, you can often make the conversion without changing either the pipes or the main expansion valve.

Where is it not the go-to?

• Air conditioning systems. Another mix, R-407C, is often used for AC.
• Systems with subcooled and flooded evaporators.
• Applications where the lubricant stands a chance of separating; turbochargers and some connectors.

So, focus on refrigeration, especially retrofits for R-22 and R-404A and avoid air conditioning or systems with flooded evaporators.

Advantages and Benefits of R-407A

Alright, let’s talk wins. Why would you pick R-407A?

• Lower Global Warming Potential (GWP). This is the big one. It’s GWP is right around half that of R-404A (just shy of 3900) @ approximatley 2100. This makes it a more environmentally benign option than the refrigerants it replaces.
• Non-Ozone Depleting. It does not harm the ozone layer.
• Similar Performance Profile. It has similar performance to R-22 and R-404A in the applications it is intended for. It means it is good for the retrofits.
• Savings with R-404A) and efficiency improvements. You will see some improvement in efficiency when going from R-404A sincelower pressure drop and less refrigerant flowing through the coil will be utilized. This in turn leads to reduced operating expenses.
• Cost-Effective (Long-Term). Efficiency gains and a lower mass flow can also mean fewer refills and lower energy bills, so it ends up being a budget-friendly investment.
• Reliable Cooling. It performs consistently in its appropriate refrigeration applications.
• Regulatory Compliance (compared to R-404A). By selecting R-407A you can meet new regulations that are phasing down the use of high-GWP refrigerants such as virgin R-404A. F-Gas ready where R-404A is limited.
• Approved by Compressor Manufacturers. It’s widely approved by major compressor makers.

So, if you are running R-22 or, especially, R-404A in medium to low temp refrigeration, R-407A makes good molecules for the environment, right?…not to mention efficiency improvements and a little insurance against changing regulations.

R-407A Pros and Cons and Considerations

Nothing’s perfect, right? And this is where R-407A has its gotchas and drawbacks:

• Temperature Glide. We talked about this. The ~8°F glide is why you don’t have a set temperature for boiling/condensing. This isn’t a deal breaker but it is one more variable you have to consider when you’re sizing equipment like compressors and running your system. You have to account for bubble and dew points.
• Decreasing Energy Efficiency at Very Low Temperatures. Below about -20°F (-29°C), R-407A requires much more compression work than R-404A to do the same work. If your system is running non-stop in ultra-low temp ranges, then a different refrigerant may be a better match.
• Moderate GWP. Much better than R-404A is still not “low” a GWP of 2107 is “moderate”. To get a sense of scale we can say that1 kg leaking is close to 2 tonnes of CO2.
• Interim Solution. R-407A is generally considered a bridge or a temporary solution. For systems with medium GWP, refrigerants with even lower GWPs are being developed (see also Table1 ). Only as an intermediate solution are these classed as acceptable with a medium GWP. The regulations keep ratcheting down to the point where they are looking for even lower-GWP solutions.
• Compression Power/Ratio. Even in medium temp (~20°F) I suppose you can require higher compression ratio (~31%) than R-404A, but other efficiencies may overcome it.

So the glide requires management, and its performance sags in ultra-low temps. And while it’s an improvement, its GWP isn’t as low as could be, meaning it’s probably not the very end destination in the refrigerant journey.

Use, Installation and Conversion R-22 Systems

Switching to or selecting R-407A isn’t simply a matter of pouring it in. There are certain steps and factors.

1. Type of Oil: R-407A is a HFC blend. The use of HFCs requires that they use synthetic oil, Polyolester (POE) oil. Mineral oil, which is commonly used with R-22 (HCFC), is not miscible with R-407A. If you are retrofitting an R-22 plant you need to remove the mineral oil and put in POE oil.

2. Charging Procedure: R-407A is always charged in the liquid. fordiscool wrote: This is essential for Z blends to prevent fractionation and getting the correct mix into the system.

3. Retrofitting R-22: R-407A was formulated to closely approximate R-22 properties. This frequently permits conversion without repiping. But for a proper retrofit, you need more than the mere swapping of oil and refrigerant. You’ll likely need to:

• Replace the original mineral oil with POE oil.
• Change the filter dryer. Use dryers for HFC’s, like those used for R-407C, R-404A or R-507.
• Test and possibly replace Safety valves and other items set for R-22 pressures.
• Either change your rubber O-rings to ones made of plastic O-rings, which are recommended when transitioning from HCFC (like R-22) to HFC.
• Vent the system and even set the expansion valve if necessary. * R-407A has less flow than R-404A and R-507A, so note the valve setting when replacing these refrigerants.

4. Amount: Total Charge Weight -R-22 Conversions: the total charge weights of these equipment could be around 195% of the R-22 equipment. Replace R-404A or R-507A with the same charge size, making adjustments subsequently. That typical charge might be 5% to 7% over the amount required by R-404A or R-507A.

5. Lubricant Level Inspection: After initial start-up conversion from R-22 and charging with R-407A, check the compressor lubricant level. If it’s low, fill it with POE lubricant until it reaches the maximum fill limit.

6. Operating Pressure: You will need to be applying pressure-temperature charts for the glide, knowing bubble and dew point pressures depending on where you are attempting to pull the target temperature you are looking for in the condenser or evaporator. 150mm and its pressure at 72°F are as follows: Liquids: 168.6 psia, Vapor: 146.4 psia. Don’t forget to subtract atmospheric pressure to convert from absolute (psia) to gauge (psig).

Fitment isn’t as simple as just exchanging fluids, though, and the car will need some technical know-how and modifications. It’s why these jobs are what they are and need to be performed by certified technicians.

R-407A in the Regulatory Landscape

Refrigerants are not only chemicals but are also controlled substances. R-407A is compatible with this environment.

As we discussed, its GWP is 2107. This is much less than R-404A’s GWP (~3900). This distinction was a large reason R-407A saw a market opportunity as regulations such as Europe’s F-Gas regulation and the U.S. AIM Act impose HFC phasedown targets for consumption and production, which R-404A was then subject too. For instance, virgin R-404A has been prohibited for servicing equipment above a certain charge size in Europe since 2020, as well as in several U.S. state. R-407A provides a solution for those compliance requirements.

But R-407A is not classified as a low-GWP refrigerant, because the GWP for R-407A is 2107. It is widely considered a stopgap as the industry shifts to refrigerants with far lower climate impact. Newer options such as R-448A and R-449A have lower GWP values (about 1387-1397). R-407A’s ultimate regulatory fate is also uncertain with the possibility for future phase-down restrictions to apply.

Another hot topic: PFAS. With the exception of R-32, at least some PFAS chemistry is found in most refrigerants (both HFCs and HFOs). As R-407A has in its make-up the R-32, R-125 and the R-134a, it itself does include PFAS (R125 and R134a). The PFAS in refrigerants like these are not listed in the groups identified by the EPA to have a negative impact on the environment or human health according to findings that at least one source referenced; they are not considered bio-cumulative or toxic.

So, R-407A is a responsible alternative to older, high-GWP options such as R-404A, but it’s one of many steps toward an environmentally friendlier choice of refrigerants.

Where to Buy R-407A

Looking for some R-407A? You can get it from a number of suppliers. Here are the names sources bring up:

• Weitron
• National Refrigerants Ltd
• Royal Refrigerants
• Johnstone Supply
• National Refrigerants, Inc. (US)

It is there in different cylinder sizes.

Important: You must be EPA certified to purchase and install R-407A in the United States. And, you’ll probably need a 608 Certification. Verification will be needed from suppliers.

So, find a reputable distributor, and make sure you or the person handling it is properly certified.

Conclusion: The Path of R-407A

R-407A. It’s a blend of refrigerants — R-32, R-125 and R-134a. It was first designed to replace both R-22 and eventually became the go-to replacement for R-404A. It’s just slightly better than R-404A and that’s why Zero Zone chose it: It is the greener solution more likely to enable compliance to regulations eliminating higher-GWP offerings. It is an R-22 and R-404A replacement for all low and medium temperature refrigeration applications.

But don’t forget the temperature glide — it’s a real thing that you’ll have to deal with. And it loses efficiency in very low-temperature conditions. It is a big step in the right direction environmentally from R-404A but it’s also a moderate-GWP and probably a bridge to the future of even lower GWP refrigerants.

When you want to retrofit R-22 or R-404A systems in cold stores, supermarkets or even transport refrigeration, R-407A is a good retrofit option, especially in applications where R-404A performs poorly and in applications that require small cooling temperatures. Just pay attention to how you transition – you’ll end up quitting the old oil in your system and switching to POE, also liquid charging and checking everything in the system is a must.

It’s a good player for today, balancing performance and environmental responsibility as the industry’s swing from dirty coal gathers force.

R-407A FAQ

Need quick R-407A questions answered? Here are a few answers pulled from the sources:

Q: What is R-407A used for? A: We use it primarily for medium and low-temperature refrigeration. That includes things like supermarket refrigeration, food storage and refrigerated transport.

Q: Can R-407A be used as a substitute for R-22? A: Yes, it is a popular replacement for R-22, particularly because performance is so close, making it ideal for retrofitting installed systems.

Q: How does R-407A differ from R-404A? A: Both are refrigerant blends, but R-407A is more environmentally friendly and has a much lower GWP (approximately 2100 vs ~3900 for R-404A). R-407A is commonly used in a retrofit for R-404A. R-407A can provide greater efficiency than R-404A, but the efficiency of R-407A falls off more at very low temperatures.

Q. What’s the distinction between R-407A and R-407C? A: They’re both R-22 replacements, so yes. But they serve separate purposes. R-407C is for air conditioning and R-407A is for refrigeration. R-407A has a lower GWP than R-407C and is more efficient than R-407C for refrigeration.

Q: Does R-407A have temperature glide! A: Yes, R-407A is a zeotropic mixture and there is a temperature glide. Sterne et al. (2001) describe a glide of about 8°F, or 6.4°C Sterne et al. (2001) describe a glide of about 8°F, or 6.4°C (approximately 11.5°F). That is, it boils and condenses over a certain temperature span.

Q: Is a specific oil required with R-407A? A: Yes, synthetic Polyolester (POE) oil must be used with R-407A. If the system you are retrofitting contained mineral oil (as do systems originally charged with R-22), you must switch to POE oil.

Q: What are the proper charging procedures for R-407A in a system? A: It is recommended to charge the system with R-407A in the liquid state.

Q: Is R-407A non-flammable and safe to use? A: Yes, R-407A is in the ASHRAE Safety Group A1, which indicats that it is non-toxic and non-flammable.

Q: Where can I buy R-407A? A: It can be purchased at refrigerant suppliers. Don’t forget that in the U.S. it’s regulated and you must be EPA certified to purchase and handle it.

That’s the scoop on R-407A.