To address the challenge of decarbonization, heat pumps play a vital role thanks to their ability to extract energy from natural sources—such as air, water, or the ground—while significantly reducing CO₂ emissions. This makes them one of the most effective technologies for building a sustainable and energy-efficient future. Continuous advancements in design, refrigerants, and operational performance are broadening their range of applications, further reinforcing their position as a cornerstone of low-carbon energy systems. 

Want to learn more? Click here to explore the importance of heat pumps in decarbonization and discover their benefits across a wide variety of applications. 

Refrigerants by type 

Over the years, a wide range of refrigerants has been developed, each characterised by distinct properties and environmental impacts. The main categories available on the market include: 

• Hydrofluorocarbons (HFCs) 
  Common examples: R-134a, R-410A 
  These are widely used but have relatively high Global Warming Potential (GWP). 

• Hydrofluoroolefins (HFOs) 
  Common examples: R-1234ze, R-1234yf 
  Known for their low GWP and improved environmental profile. 

• Natural Refrigerants 
  Common examples: R-717 (Ammonia), R-290 (Propane), R-744 (Carbon Dioxide) 
  These offer excellent thermodynamic performance and minimal environmental impact, though they may pose safety or handling challenges. 

• Blended Refrigerants 
  Common examples: R-513A (R-1234yf + R-134a), R-454C (R-1234yf + R-32), R-515B (R-1234ze + R-227ea) 
  Designed to balance performance, safety, and environmental considerations. 

The choice of refrigerant depends on several factors, including application requirements, system design, safety considerations, and regulatory constraints. Each option presents specific advantages and trade-offs. The industry trend is increasingly shifting toward refrigerants with low GWP and zero Ozone Depletion Potential (ODP) to reduce environmental impact and comply with evolving sustainability standards. 

Typically, due to the chemical and physical properties of refrigerants, each one is associated with specific types of compressors. This combination is based on both the technical characteristics of the compressors and the operational requirements of the refrigerants. As a result, choosing a particular refrigerant for a heat pump inevitably involves selecting a compatible compressor type. 

Click here to explore the different types of compressors. 

Want to know more? Please contact us.  

HVAC market, regulatory trends and Daikin refrigerant options for heat pumps 

In recent years, there has been growing attention regarding refrigerants, especially in relation to European regulations on fluorinated gases (F-Gases). As a result, the use of refrigerants R-134a and R-410A has been progressively reduced. The latest version of the F-Gas regulation establishes that, starting from 2027, these two refrigerants will no longer be allowed for use in Europe. Therefore, it is necessary to shift towards alternatives with a low global warming potential (GWP), such as R-32, and R-1234ze. Currently, the market transition towards natural and low-GWP refrigerants is accelerating significantly. 

In this regard, Daikin’s portfolio is perfectly suited to market evolution and current needs. Daikin heat pumps using low-GWP refrigerants are already available today.  

Click here to learn more and explore the full range. 

Furthermore, Daikin has recently announced the development of a new air-to-water heat pump that uses propane as a refrigerant. This demonstrates Daikin's ability to offer innovative, sustainable solutions that fully align with market demands. 

Technical specifications of refrigerants: an overview 

Global Warming Potential 

Global Warming Potential (GWP) is a metric used to quantify the amount of heat a greenhouse gas traps in the atmosphere over a specific time horizon, typically 20, 100, or 500 years, relative to carbon dioxide (CO₂), which has a reference GWP of 1. This standardised measure allows for the comparison of the climate impact of different gases. 

The GWP values for refrigerants are defined by the Intergovernmental Panel on Climate Change (IPCC), the United Nations body responsible for assessing the science related to climate change. The IPCC publishes comprehensive Assessment Reports that summarise the current scientific, technical, and socio-economic knowledge on climate change. 

Toxicity and flammability 

ASHRAE Standard 34 assigns a unique alphanumeric designation to each refrigerant, classifying it based on its toxicity and flammability hazards. 

• The capital letter indicates the toxicity class, based on permissible exposure limits: 

• Class A: Lower toxicity 

• Class B: Higher toxicity 

• The numeral represents the flammability class: 

• Class 1: Non-flammable (does not propagate a flame under test conditions) 

• Class 2: Low flammability 

• Class 3: High flammability (e.g., hydrocarbons like propane) 

In addition, ASHRAE has introduced a subclass 2L within Class 2 to identify refrigerants that exhibit very low burning velocity, offering a more nuanced understanding of flammability risks. 

While these classifications provide a standardised safety framework, it’s important to note that extreme ambient conditions, combined with the chemical nature of the refrigerant, can still lead to increased toxicity or flammability risks. 

Thermodynamic properties 

Refrigerants used in heat pumps must possess specific thermodynamic properties to ensure efficient and reliable heat transfer. The most important characteristics include: 

• Boiling Point: A low boiling point is essential to enable the refrigerant to evaporate at low temperatures, facilitating the phase change from liquid to gas during heat absorption. 

• Latent Heat of Vaporization: A high latent heat allows the refrigerant to absorb and release a significant amount of energy during phase transitions, improving the overall efficiency of the heat pump cycle. 

• Pressure–Temperature Relationship: An optimal balance between pressure and temperature ensures that the refrigerant operates effectively within the design limits of the heat pump system, maintaining performance and safety. 

The table below presents key thermodynamic parameters of some of the most used refrigerants in the HVAC industry, providing a basis for comparison and selection based on application needs. Whilst R-134a and R-410A have historically been mostly used on heat pump applications, technological and regulatory advancements in Europe have shift the attention on R-1234ze and R-32 mainly, and respectively for water-to-water and air-to-water heat pump technology. 

R-1234ze offers better performance at the compressor discharge stage, making it particularly suitable for applications requiring high condensing temperatures. For example, at a condensing temperature of +40 °C, R-1234ze operates at just 7.7 bar with a discharge temperature of 56.2 °C, compared to R-32, which requires 24.8 bar and reaches a discharge temperature of 119.7 °C. These characteristics make R-1234ze ideal for systems that deliver high supply water temperatures. 

However, R-1234ze has a relatively high boiling point of –19 °C, compared to –51.7 °C for R-32. This limits its effectiveness in air-to-water heat pump applications in colder climates. 

Conversely, R-32’s much lower boiling point makes it more suitable for air-to-water heat pumps, especially in cold environments. It enables efficient operation even at low ambient temperatures and can deliver supply water temperatures up to 60 °C. While R-32 excels in these conditions, R-1234ze performs best in water-to-water heat pumps, where the heat source—such as groundwater or a closed water loop—maintains stable, positive temperatures. In these settings, R-1234ze’s lower pressure and higher critical temperature allow it to operate efficiently. 

In line with market trends, Daikin is offering different refrigerant options on its heat pump range.

Take a look at Daikin’s heat pumps portfolio to know more. 

Operating limits of heat pumps 

The operating limits of a heat pump are influenced not only by the refrigerant properties but also by several system-level factors such as the compressor type, motor design, lubricating oil, and heat exchanger configuration.  

To illustrate the combined effect of these variables, we can refer to a generic operating envelope for an air-to-water heat pump. This envelope helps define the practical boundaries within which the system can operate reliably and efficiently, considering both refrigerant properties and system-level constraints. 

1. Minimum Pressure Ratio: Adequate pressure difference between suction and discharge is needed to ensure oil circulation, which lubricates, seals, and cools the compressor. 

1. Maximum Motor Current: Higher suction and discharge pressures increase torque and motor current, leading to heat generation that risks motor damage if not controlled. 

1. Maximum Operating Pressure: Limited by refrigerant critical pressure and component ratings, which must meet safety regulations and design standards. 

1. Maximum Discharge Temperature: High pressure ratios raise discharge temperatures, potentially damaging compressor materials and lubricants; cooling methods like oil coolers or refrigerant injection help manage this. 

1. Minimum Evaporating Pressure: At low ambient temperatures, suction pressure drops, affecting motor cooling by refrigerant; unloading and VFDs help maintain motor cooling and stability. 

The operating limits of refrigerants and compressors are a key factor in heat pump development. Thanks to its ongoing technological innovation, Daikin is able to overcome these limitations by offering high-performance solutions such as the EWYE-CZ, an air-to-water heat pump capable of supplying hot water up to 70 °C even with ambient temperatures as low as –15 °C, and the EWWH-VZ, a high-temperature water-to-water series that can deliver hot water up to 90 °C. 

Click here to learn more about the EWWH-VZ series. 

About operating range of Daikin heat pumps 

Daikin technological development efforts have enabled to expand the application range of heat pumps, particularly with the EWYE-CZ and EWWH-VZ heat pumps. 

The EWYE-CZ air-to-water heat pump features Daikin’s advanced Inverter Scroll compressor technology and uses the environmentally friendly R-454C refrigerant. This combination ensures both high efficiency and sustainability. The unit can produce hot water up to 70 °C, making it an excellent solution for decarbonizing residential heating. Available in eight sizes ranging from 16 kW to 70 kW. The operating range allows water supply temperatures from 20 °C to 70 °C, even under extreme conditions such as harsh Nordic winters or summer periods requiring domestic hot water. It can operate at high delta T values, enabling hot water delivery to multiple heating applications within the system, with ambient operating temperatures between –25 °C and 40 °C. This unit features four compact versions featuring one to four inline fans, designed for maximum space efficiency and performance. An integrated Inverter water pump further simplifies installation and optimizes space usage. Despite its capacity, the EWYE-CZ has a minimal footprint, making it ideal for space-constrained projects such as residential buildings, hotels, and hospitals. A low-noise variant is also available for noise-sensitive environments. It can provide reliable heating and domestic hot water production, equipped with an anti-legionella control function for the external tank. It features one or two independent refrigerant circuits using R-454C refrigerant, classified as A2L under ISO 817 and ASHRAE 34 standards. Thanks to its low toxicity and flammability, R-454C requires no additional safety measures, making this range one of the most advanced and comprehensive decarbonization solutions on the market. 

The EWWH-VZ is new high-temperature option for its VZ series, featuring the R-1234ze refrigerant to extend the operating range of existing models. This upgrade allows the unit to supply hot water up to 90 °C, broadening its suitability for diverse applications and covering capacities from 10 to 2,400 kW.  

The Daikin EWWH-VZ water-sourced heat pump combines exceptional energy efficiency with a low environmental footprint. Using R-1234ze, a refrigerant with very low Global Warming Potential (GWP), it delivers cooling and heating capacities from 400 to 1900 kW*. Its compact design and full inverter technology ensure optimal performance and flexibility to meet various operational demands.  

Visit the Heat Pumps page to explore the full portfolio and find the ideal solution for your needs. 

Introducing this new high-temperature option marks a significant step toward industrial heating decarbonization. By expanding the operating envelope, the EWWH-VZ series suits many applications—including industrial processes and district heating networks—that require high-temperature hot water. This feature is especially valuable for industrial uses such as cleaning, sterilization, and production processes needing elevated water temperatures. 

Frequently Asked Questions on Daikin Heat Pumps   

Where are Daikin heat pumps manufactured? 

Daikin heat pumps are manufactured in Italy, at the headquarters and heart of Daikin Applied Europe, located in Ariccia (Rome). This factory is dedicated to  producing high-quality HVAC equipment, including two main types of heat pumps: air-source and water-source.   

Cick here to visit Daikin chillers product page.   

Click here to visit Daikin heat pumps' product page.   

How to purchase a Daikin heat pump?   

Click here to send us a contact request and get more support for your needs   

How to rent a Daikin’s heat pump?   

Get in touch with us for additional support by clicking here.   

How to get support for Daikin heat pumps?   

Click here to get all the assistance you need.   

How to buy spare parts for a Daikin heat pump?   

Contact us for more information.    

What compressor types are Daikin offering on heat pumps? 

Check out our in-depth article on compressors for heat pumps to learn more or explore our dedicated sections on water-to-water heat pumps, air-to-water heat pumps, and multipurpose units. 

What refrigerants is Daikin using on heat pumps? 

Discover more by visiting our product page dedicated to heat pumps.