SEER2 and ERP Efficiency Labels Explained
Efficiency labels cause more confusion than almost any other figure in air conditioner buying, because two different rating systems use similar-looking numbers for different things. This guide explains both systems as they appear in this range, and why they must not be compared directly.
SEER2: the North American seasonal rating
SEER2 is the North American seasonal energy efficiency ratio, and it appears in this range in the product-centre titles for the Rex R454B wall split, described as SEER2 23–24, and the SEER2 24 split inverter, described as SEER2 24. SEER2 measures seasonal cooling efficiency under North American test conditions, with a test procedure that differs from the European procedure in temperatures, cycling and duct assumptions. A higher SEER2 number means higher seasonal cooling efficiency within the North American system, and it is the right figure for comparing two North American models with each other. It is not a figure that can be converted into a European label, and a buyer who converts it — by a rule of thumb, a chart found online, or a supplier's informal equivalence — will produce a number that neither rating system supports. The correct use of SEER2 is narrow: compare North American models with North American models, for the same capacity step, and ask for the test documents if a regulatory filing needs them.
ERP and A+++: the European labelling description
The European descriptions in this range use the ERP framework and the A+++ label: the Origin A+++ R32 model, the Premium A+++ R32 model and the Aeolus split heat pump, described with ERP A+++, all carry that language. ERP — energy-related products — is the European framework that sets efficiency and labelling rules, and A+++ is the top label class within the labelling scale as presented in these listings. Like SEER2, the European label is a system, not a single number: it reflects seasonal performance under European test conditions, and it cannot be converted into SEER2. A buyer comparing a European A+++ model with a North American SEER2 model is therefore comparing two different tests, and the comparison should stop at the system boundary. Instead, the buyer should compare models within one system — European with European, North American with North American — and should choose the system by market, not by which label looks higher.
Rated ratios: EER and COP
Alongside the seasonal labels, several model pages list rated ratios: EER for cooling and COP for heating, at rated conditions. The Aeolus models list EER around 3.15–3.16 and COP around 3.18–3.20 in watts per watt, the floor standing model lists EER 3.15 and COP 3.22, and the Rex model lists an EER of 13 in BTU per watt-hour with a COP of 3.81. The Rex EER looks different because it uses the North American unit convention, not because the model is an order of magnitude more efficient — a unit difference, not a performance difference. Rated ratios describe performance at one set of conditions, while seasonal labels describe performance across a season, so the two kinds of figure should not be ranked against each other either. The practical rule for buyers is to use each figure only within its own system, to compare like with like, and to ask for the documents behind any figure that will be used in a regulatory filing or a customer guarantee.