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REFRIGERATION

Comparison

R290 (propane) vs R600a (isobutane)

R290 (refrigeration-grade propane) and R600a (refrigeration-grade isobutane) are both hydrocarbon refrigerants with very low global warming potential and no ozone impact. Both are highly flammable and are used in sealed systems with small charges. The difference is in their pressures and cooling capacity. R600a works at low pressures and suits small, efficient systems such as household refrigerators and compact coolers. R290 has much higher cooling capacity per unit volume, closer to older refrigerants used in commercial equipment, which makes it suited to larger cabinets and freezers.

R290 (propane) compared with R600a (isobutane)
R290 (propane)R600a (isobutane)
Global warming potentialVery low, in single digits.Very low, in single digits.
FlammabilityHighly flammable (A3).Highly flammable (A3).
Operating pressureModerate to high, similar to older commercial refrigerants.Low. The suction side can run below atmospheric pressure at freezer temperatures.
Cooling capacity per volumeHigh. A smaller compressor delivers more cooling.Lower. Needs a larger compressor displacement for the same capacity.
Typical equipmentCommercial reach-ins, visi coolers, chest and upright freezers, display cases and some ice-cream equipment.Household refrigerators, small bottle coolers and compact commercial units.
EfficiencyGood across commercial duties, including freezers.Very efficient in small, low-capacity systems.
Leak behaviourLeaks outward due to positive pressure.A low-side leak in a freezer can draw air and moisture into the system, which complicates repair.
ServicingRequires hydrocarbon training, proper tools and ventilation.Same training needs. Compressors and parts are widely produced for the household market.
Hot-ambient performanceHolds capacity well in hot rooms, which suits non-AC Indian shops and kitchens.Capacity drops off more noticeably in very hot rooms because the system is already small.
Charge in a typical unitTens to a few hundred grams, within the limits set by safety standards for commercial appliances.Usually a very small charge, often well under a hundred grams in household-sized units.

Choose r290 (propane) when…

  • You need a commercial refrigerator, freezer or display case with meaningful cooling capacity.
  • The unit will run in hot ambient conditions and needs margin to pull down quickly.
  • You want a low-GWP option for freezers and larger plug-in cabinets.
  • Door openings are frequent and fast recovery matters.

Choose r600a (isobutane) when…

  • You need a small, low-capacity cooler, such as a counter-top or single-door bottle cooler, where efficiency per watt is the priority.
  • The unit is close to household duty: few openings, small volume, steady load.
  • You want a compact bottle cooler or counter-top unit.
  • Parts commonality with household-type compressors is useful for your service network.

The verdict

These are not rival choices for most buyers. The refrigerant follows the equipment: manufacturers pick R600a for small, low-load systems and R290 for commercial duty and freezers. If you are comparing two similar commercial units and one uses R600a, ask whether it has enough capacity for your ambient temperature and door-opening pattern. Both refrigerants are low-GWP and both need trained service, so the practical questions are capacity, efficiency and service availability rather than environmental impact. For Indian conditions in particular, capacity margin matters: a cabinet that copes at 32 °C may struggle at 43 °C with the door opening every minute. That is where R290's higher capacity is useful. For a small cooler in an air-conditioned café with light traffic, R600a's efficiency is hard to beat.