R407C is a popular refrigerant used primarily in air conditioning systems, as well as in heat pumps and refrigeration. It belongs to the group of fluorinated greenhouse gases (commonly referred to as F-gases) and is a blend of three components: R32, R125, and R134a – making it a synthetic mixture, i.e., the result of combining other refrigerants. The proportions of these gases were selected to achieve cooling properties similar to the phased-out R22 refrigerant (discontinued for environmental reasons), while reducing its negative impact on the ozone layer. R407C is a zeotropic refrigerant, meaning that during phase change, its boiling or condensation temperature varies within a certain range (known as "glide"). It was designed to be easier to handle, less expensive, and relatively eco-friendly (by the standards of the industry at the time).
The R407C refrigerant is widely used in air conditioning systems, particularly in split-type units and heat pumps for building heating and cooling. Due to its properties, it can also be used in medium-temperature refrigeration systems. It is compatible with synthetic POE (polyolester) oils, which must be considered during equipment servicing. R407C was often chosen as a replacement for R22 in retrofitted systems, though it requires appropriate modifications and lubricant replacement. Today, however, it is no longer considered the most advanced or environmentally friendly option, just as R22 was in the past – R407c has also become outdated.
R407C, as a fluorinated greenhouse gas (F-gas) with a high GWP (Global Warming Potential), is subject to EU F-gas regulations. This means that any work involving its charging, recovery, servicing, or installation of equipment containing it must be performed only by individuals with proper F-gas certification. This requirement ensures proper handling of the refrigerant and minimizes the risk of its release into the atmosphere, contributing to environmental protection and compliance with legal regulations.
Although R407C does not deplete the ozone layer (ODP = 0), it has a relatively high global warming potential (GWP ≈ 1774 according to IPCC AR4). As a result, it is regulated under the EU F-gas regulations. In practice, this means adhering to rules regarding system tightness, mandatory leak checks, and proper refrigerant recovery during servicing and decommissioning. Increasingly, manufacturers are considering switching to refrigerants with lower GWP, such as R32 or R454B, but R407C remains in widespread use in many older and newer systems.
R407C was introduced to the refrigeration and air conditioning industry in the mid-1990s as a response to the phase-out of R22, which had a high ozone depletion potential (ODP). It was developed as an azeotropic blend of R32, R125, and R134a to maintain performance parameters similar to R22 while meeting the environmental requirements of the Montreal Protocol. Initially, it found widespread use in split air conditioners, air handling units, and heat pumps. In the first decade of the 21st century, it was one of the most commonly used refrigerants in new installations and retrofits. Although it is increasingly being replaced by lower-GWP alternatives like R32 or R454B, R407C is still present in many operational systems, and its history illustrates the industry's shift toward more eco-friendly solutions.
Compared to the currently popular R32 – or even R410a – R407c has one major advantage. Namely, R407c operates at lower working pressures, which is a significant benefit because equipment designed for this refrigerant does not need to be reinforced for high pressures. As a result, it can be – and generally is – cheaper to manufacture. This applies to components such as condensers, evaporators, and gas heat exchangers.
At temperatures above 60°C, R407c reaches "only" slightly above 30 bar, while R32 and R410a can exceed 40 bar. This is a clear drawback of R32, which is often overlooked in public discourse. This means that by replacing R407c with newer, more eco-friendly refrigerants, we unfortunately limit the potential for reducing heat pump prices (at least to some extent). And like any technology, they should, over time, become more affordable as availability increases and more manufacturers and distributors enter the market.
There are also refrigerants that perform slightly better than R407c in terms of working pressure. One example is R134a. However, it too is being phased out for environmental reasons (and is already subject to strict regulations in the EU).
R407C is an efficient and well-proven refrigerant that performs well in air conditioning and heat pump systems. Its biggest advantage is its similarity to R22, making it a convenient replacement in retrofits. However, due to its high GWP, it requires responsible use and compliance with environmental regulations. Understanding its properties is crucial for both installers and users who want to maintain their equipment in good technical and legal condition. However, it must be clearly stated that as a synthetic blend, it is no longer the favorite of the market, regulators, or the climate lobby. It is losing the competition to R32 and R290.
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