Refrigerants
Overview of refrigerants used in HPWHs — comparative properties, GWP, and detailed pages for CO₂, R290, and R-1234yf.
Refrigerant choice directly affects HPWH performance, cost, safety, and environmental impact. In the past, synthetic refrigerants (R134a, R410A) were standard, but the industry has shifted toward natural, low-GWP alternatives — particularly CO₂ (R744) and propane (R290).
No refrigerant perfectly balances thermal efficiency, safety, cost, and environmental impact. The table below summarises the most common options.
Detailed pages: CO₂ (R744) · Propane (R290) · HFO R-1234yf
The table below compares the most common refrigerants.
| Refrigerant | Pros | Cons | GWP |
|---|---|---|---|
| CO2 (R744) | Quiet operation. Highly efficient. Higher outlet temperature up to 90degC. | Higher upfront manufacturing costs. Safety concerns (high pressure) may require additional precautions. | 1 |
| Propane (R290) | Low manufacturing costs. Widely available raw materials. Good thermal efficiency. | Highly flammable, necessitating stringent safety measures during production and use. | 3 |
| R32 | Relatively low manufacturing cost. | Limited availability of raw materials may impact production. Mild flammability can pose risks. Maximum 60degC. | 675 |
| R1234yf | Increasing availability globally. | Higher manufacturing costs compared to some alternatives. Mild flammability. | 4 |
| R134a | Established manufacturing capabilities contribute to lower costs. | High GWP, being phased out from July 2024 | 1430 |
| R410A | Widely used in air conditioning and heat pump systems. | High GWP, being phased out from July 2024 | 2088 |