Heat pumps are becoming - of course - an increasingly popular solution for single-family homes and commercial buildings. This is mainly due to their high energy efficiency and the ability to both heat and cool a building in a maintenance-free, relatively inexpensive way (at least in new construction buildings), and partly also thanks to the appropriate policy of the European Union aimed at subsidizing this type of solutions. When choosing a heat pump, we sometimes come across mysteriously sounding indicators such as ODP or GWP, referring to the refrigerants used in a given heat pump. In this post, we will focus on the GWP indicator - what it is, what it means, and what significance it has.
GWP is an abbreviation of the English term Global Warming Potential, meaning "potential to create a greenhouse effect". This parameter determines how much a given gas influences climate warming compared to carbon dioxide (CO₂). It has been agreed that GWP for CO₂, i.e., for carbon dioxide, is 1. So if a refrigerant in a heat pump has a GWP of 675, it means that over 100 years its impact on the greenhouse effect will be 675 times greater than the same charge of CO₂.
So GWP refers not to the heat pump itself, but to the gas (refrigerant) used in it. It therefore indicates how eco-friendly a given type of heat pump will be - although of course GWP is not the only factor determining whether a given device is eco-friendly or not. Besides "Global Warming Potential", there are also indicators such as ODP (ozone depletion potential) or the most important one - COP - showing how much electrical energy the heat pump must consume to produce a given amount of heat.
Heat pumps use refrigerants (so-called working fluids) that are responsible for heat transport in the system. Unfortunately, in case of leaks, they can escape into the atmosphere. If the refrigerant has a high GWP, even a small amount of its emission can affect the environment. Therefore, increasing emphasis is placed on using refrigerants with the lowest possible GWP, and in the European Union, there are regulations that gradually limit the use of the most harmful ones - the trend has of course significantly accelerated with the emergence of the Green Deal policy.
So GWP is important for people who identify with the need to care for the climate and live in accordance with ecological trends. But it also has practical legal significance - because we live in times when European authorities are actively involved in creating guidelines for the heat pump market and in time it will turn out that those using old refrigerants with a high GWP index - will be eliminated from the market anyway.
Currently, refrigerant R32 is gaining great popularity, which has a GWP of 675 – significantly lower than the older R410A (GWP 2088). Even more beneficial for the environment are natural refrigerants, such as propane (R290), whose GWP is only 3, or carbon dioxide (R744) with a GWP equal to 1. By choosing a heat pump with such a refrigerant, an investor can significantly reduce the carbon footprint of their installation.
In the table below, you will find examples of refrigerants along with their GWP. It can be noticed that those with a high GWP index - such as R410a or R134a - are currently being phased out from the market based on EU policies, and replaced by those with lower GWP.
| Refrigerant | Refrigerant type | GWP (100 years) | Remarks |
|---|---|---|---|
| R410A | Synthetic | 2088 | Being phased out in the EU, high climate impact |
| R32 | Synthetic | 675 | Lower GWP, currently commonly used |
| R290 | Natural (propane) | 3 | Very low impact, requires fire protection measures |
| R744 | Natural (CO₂) | 1 | Most climate-safe, requires high operating pressures |
| R134a | Synthetic | 1430 | Less commonly used in heat pumps |
GWP is a key parameter worth considering when purchasing a heat pump if environmental protection is important to us. The lower its value, the smaller the negative impact of the device on the climate – especially in case of potential working fluid leaks. A conscious choice of a model with low GWP is a step towards ecology, but also an investment in line with trends and future legal requirements. If we ourselves do not feel the need to be guided by a low GWP index when purchasing heat pumps - it is worth remembering that in time the European Union will make this decision for us - as devices adapted to gases with high GWP will simply be legally banned.
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