GB/T 18837-2026 Takes Effect, Adding A2L Refrigerants and Revising Efficiency Evaluation

GB/T 18837-2026, the new standard for multi-split air-conditioning and heat pump units, took effect on November 1, 2026, replacing the 2015 edition. It introduces a revised approach to evaluating energy efficiency and brings A2L mildly flammable refrigerants, including R32 and R454B, within its scope for the first time.

The standard differentiates unit types by application and uses a nominal cooling capacity of 20,000 W as a threshold for evaluation. This means that the applicable evaluation category depends on how a unit is classified, making both its intended application and rated capacity important when interpreting its efficiency figures.

Why Efficiency Figures Need Context

Because the evaluation methods differ substantially between the two editions, energy-efficiency parameters for the same unit cannot be compared directly across the old and new standards. A change in a published figure alone should therefore not be treated as evidence that the unit itself has become more or less efficient.

The immediate implications are likely to be most visible in product documentation and comparisons: manufacturers may need to update product data, while buyers and specifiers will need to check which edition underlies each figure. The addition of A2L refrigerants also broadens the standard's scope, although its inclusion does not by itself establish that any particular product uses them.