Natural Refrigerant or HFC: Which to Choose for a Refrigeration Installation
Choosing between a natural refrigerant and an HFC affects investment, energy use, safety and how well you adapt to future restrictions. Here is how to compare them properly.
Ingeniería Isofred
Departamento Técnico - Isofred
Choosing between a natural refrigerant and an HFC is not about comparing gas prices. The decision affects investment, power consumption, safety, maintenance and how well the installation will cope with the restrictions of the next 15 to 20 years.
Natural refrigerants (ammonia, CO₂ and hydrocarbons) have a very low global warming potential (GWP). HFCs are proven technology, but the EU market is cutting them back year after year and restricting their use and servicing according to GWP and application.
Quick answer
For a new installation with a 15–20 year life, a natural or very-low-GWP refrigerant deserves serious consideration. Keeping an HFC can make sense for existing equipment, but before investing, check its future availability, taxation, servicing restrictions and conversion options.
0
GWP of ammonia (R717)
1
GWP of CO₂ (R744)
≈ 3
GWP of propane (R290)
What is a natural refrigerant?
It is a substance found in nature that is used as a refrigerant. In industrial refrigeration the most common are ammonia and CO₂; propane is mainly used in packaged units and chillers with limited charge. “Natural” does not mean “risk-free”: each one changes the type of risk that has to be managed.
| Refrigerant | Strength | Risk to manage |
|---|---|---|
| Ammonia (R717) | Excellent industrial performance | Toxicity and low flammability |
| CO₂ (R744) | Non-flammable, GWP 1 | Very high operating pressures |
| Propane (R290) | Efficient and compact | Highly flammable: limited charge |
What are HFCs?
Hydrofluorocarbons are synthetic refrigerants (R134a, R404A, R407F, R410A, R448A, R449A, R513A…; some are blends with HFOs) that replaced CFCs and HCFCs because they do not harm the ozone layer. They brought familiar technology, standard components, moderate pressures and, in many cases, an A1 non-flammable rating. Their problem is climate: many have a high GWP, so a leak is equivalent to emitting thousands of times the same amount of CO₂.
Natural refrigerant vs HFC: main differences
| Criterion | Natural refrigerants | HFCs |
|---|---|---|
| GWP | Very low | Variable, often high |
| F-gas rules and tax | Outside the HFC phase-down and Spain's HFC tax | Quotas, restrictions and tax by GWP |
| Safety | Toxicity, flammability or high pressure, depending on the gas | Many A1; low-GWP substitutes are often A2L |
| Upfront investment | Can be higher | Lower for conventional systems |
| Refrigerant price | Low and stable | Variable, exposed to availability |
| Service expertise | Requires specialists | More widespread |
| Future regulatory risk | Low | May force replacement or conversion |
An oversized natural-refrigerant solution is not justified for a small unit either. The table is a guide; the decision is made with the numbers for each case.
How much does each option cost?
HFCs usually win on upfront cost thanks to standardised equipment. Natural refrigerants can cost more because of high-pressure components (CO₂), the machinery room and safety measures (ammonia) or charge limits (propane), plus detection, ventilation, automation and training. In large industrial plants, however, ammonia is highly competitive and lasts for decades.
With the refrigerant itself, the price per kilo is misleading: total charge, leaks and top-ups are what count. In Spain, fluorinated gases carry a tax calculated as 0.015 times their GWP, capped at €100 per kilo (gases with a GWP of 150 or less are exempt). In a system holding hundreds of kilos of a high-GWP HFC, that adds up both in the initial charge and in every top-up. Ammonia, CO₂ and hydrocarbons are not subject to this tax.
Compare like with like
Comparing a basic HFC unit with a CO₂ plant that includes redundancy, heat recovery, monitoring and several temperature levels is not a fair comparison. Costs must be compared between solutions that do exactly the same job.
Which one uses less energy?
Electricity weighs far more over an installation's life than the price of the gas, and it depends more on design than on refrigerant: evaporating and condensing temperatures, climate, load profile, capacity control, heat exchangers, defrosts and maintenance. Ammonia performs very well in large plants running long hours; CO₂ excels in freezing, cascades and logistics centres, especially when heat is recovered (see subcritical vs transcritical CO₂); propane suits packaged units and chillers; and a well-controlled low-GWP HFC can also be efficient. That is why Spain's RSIF requires, for similar efficiency, the refrigerant with the lowest possible GWP.
Which is safer?
Spain's RSIF (Royal Decree 552/2019) groups refrigerants into L1 (high safety, equivalent to A1), L2 (medium: A2L, A2, B1, B2L, B2) and L3 (low: A3, B3). Each option changes the type of risk:
Ammonia (B2L)
Toxic and mildly flammable. Its smell gives away small leaks, but a major release requires ventilation, detection, an emergency plan and trained staff. It works very well confined to a machinery room, with limited charge and enough capacity to justify it.
CO₂ (A1)
Non-flammable and of low regulatory toxicity, but it runs at very high pressures and displaces oxygen. Pressure must be controlled during shutdowns too, with detection at the right height and ventilation.
Propane (A3)
Highly flammable. It is safe if the charge is limited and ventilation, location, electrical components and ignition sources are properly handled.
HFCs and substitutes (A1 / A2L)
Many traditional HFCs are A1, but low-GWP substitutes are often A2L, mildly flammable. Switching from A1 to A2L is not just a gas swap: maximum charge, ventilation, materials, compressors, electrical equipment and the installation's classification all need reviewing.
What does the F-gas Regulation say?
Regulation (EU) 2024/573, in force since 11 March 2024, speeds up the HFC phase-down and adds restrictions on new equipment and servicing. It does not ban all HFCs at once: the effect depends on equipment type, capacity, GWP, date and use. Three key dates:
| Date | What changes (with exceptions) |
|---|---|
| 1 January 2025 | Gases with GWP ≥ 2,500 may no longer be used to service refrigeration equipment |
| 1 January 2030 | Certain new stationary refrigeration equipment may not use fluorinated gases with GWP ≥ 150 |
| 1 January 2032 | Servicing of stationary refrigeration (except chillers) with gases of GWP ≥ 750 is restricted |
Do I have to replace my existing HFC systems?
Not necessarily. An existing installation can still be fine if its refrigerant may still be used for servicing, it hardly leaks, its consumption is reasonable, parts and gas are available, it complies with the RSIF and it has only a few years of life left. A change is worth studying when it uses a very high-GWP HFC, leaks repeatedly, uses too much energy, needs expanding, its compressors are near end of life or the gas is becoming expensive or hard to source.
And it is almost never a matter of “just changing the gas”. A retrofit means checking oil, pressures, compressors, expansion valves, seals, heat exchangers, safety, maximum charge and documentation. Natural refrigerants are not drop-in replacements for HFCs: going from R404A to CO₂, ammonia or propane usually requires a new installation or a major overhaul.
Total cost of ownership: how to compare
Total cost of ownership (TCO)
TCO = investment + cumulative energy + maintenance + refrigerant and leaks + taxes and compliance + downtime losses − value of recovered heat.
A system that is cheaper upfront can end up costing more if it uses more energy, loses gas or has to be converted early. And the reverse is true: a very advanced natural solution may never pay back if it runs few hours, is small and does not use its heat. The comparison has to use the site's climate, real operating hours and the whole service life, not just the rules in force on the day of purchase.
Which solution usually fits each case?
| Application | Solutions to consider |
|---|---|
| Large food plant | Ammonia, low-charge ammonia or NH₃/CO₂ |
| Multi-temperature logistics centre | Transcritical CO₂, CO₂ cascade or indirect system |
| Industrial freezing | Subcritical CO₂, NH₃/CO₂ or ammonia |
| Small cold room | Packaged unit with a low-GWP refrigerant |
| Industrial chiller | Ammonia, propane, HFO or low-GWP blend |
| Plant with occupied areas | Indirect system with confined refrigerant |
| Existing installation with short remaining life | Keep, optimise or compatible retrofit |
Isofred projects with different refrigerants
Döhler (Fraga, Huesca)
Ammonia plant of over 3 MW with screw compressors for processes, cold rooms and storage (32,000 m³), later expanded for chilled and frozen storage. The classic large-industry case where ammonia is hard to beat.
Copima (Graus, Huesca)
A combination of solutions: ammonia with 35 % propylene glycol for chilled storage and air conditioning, a separate CO₂ system for freezing and R-290 (propane) for meat dry-ageing. Each refrigerant where it performs best.
VEOS (Lleida)
Refrigeration plant upgrade with high-efficiency screw compressors (500 kW) and central monitoring, using R-1234ze, a very-low-GWP HFO: a synthetic alternative where a natural refrigerant does not fit.
See more in our projects and our industrial refrigeration service.
Which mistakes come up most often?
- Choosing the gas before defining the process, or comparing only the upfront budget.
- Assuming “natural” means risk-free, or that all HFCs are banned.
- Installing an HFC without studying the coming years' restrictions or the tax.
- Choosing CO₂ without analysing the climate, ammonia without planning for safety and training, or propane without calculating the allowable charge.
- Changing refrigerant without checking compressors, valves, seals and oil.
- Not calculating annual consumption or valuing heat recovery.
Not sure which refrigerant to choose for your next installation?
We will prepare a technical and financial comparison: your process, the rules that apply to you and the total cost of each option.
Frequently asked questions
Does a natural refrigerant always use less energy? No. Consumption depends on the whole system, temperatures, climate, controls and maintenance. Natural refrigerants can be very efficient, but only with the right design.
Are all HFCs banned? No. There are progressive quotas and restrictions by GWP, application and date. Some can still be used in certain equipment.
Can I replace R404A with CO₂? Not as a drop-in. CO₂ works with different pressures and components and usually needs an installation designed for it.
Do natural refrigerants pay Spain's fluorinated gas tax? No. Ammonia, CO₂ and hydrocarbons are not fluorinated gases and are not subject to that tax.
Should I replace an HFC installation now? It depends on its refrigerant, condition, consumption, leaks, remaining life and future restrictions. An audit shows whether to keep, upgrade or replace it.
Technical note: F-gas bans and exemptions depend on equipment category, GWP, capacity and use. Before investing, check the regulation currently in force and analyse your specific installation.
