North American SEER2 and European A+++ Labels Explained
Efficiency labels are supposed to make buying easier, but when two different labelling systems meet in one catalogue, they often make it harder. This article explains the North American SEER2 system and the European ERP and A+++ system, and why a number from one must never be converted into the other.
Two systems, two test procedures
SEER2 and ERP are not two names for the same test. SEER2 is the North American seasonal energy efficiency ratio, measured under North American test conditions with North American assumptions about climate, cycling and ductwork. ERP is the European energy-related products framework, under which the A+++ label class is awarded, measured under European test conditions with European assumptions. The temperatures used, the way part-load operation is weighted, the treatment of standby power and the climate zones assumed all differ between the systems. A unit tested under one system therefore carries a number that has no exact equivalent in the other system, and any conversion chart that claims otherwise is inventing a relationship the tests do not support.
That matters because catalogues increasingly mix the two systems. A range like the one on this site contains North American models with SEER2 descriptions and European models with A+++ descriptions side by side, and a buyer who ranks them by headline number will rank them wrong. The correct approach is to compare within one system only: North American models against North American models by SEER2, European models against European models by label class, and never across the boundary. The market decides the system, not the buyer: a buyer in North America should use SEER2, a buyer in Europe should use the European label, and a buyer elsewhere should use whichever system their market's regulations recognise.
SEER2 in this range
In this range, SEER2 appears 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. Those figures are title descriptions, and they describe seasonal cooling efficiency within the North American system. A higher SEER2 figure means higher seasonal cooling efficiency, but only within that system and only for comparable capacity steps: a small unit and a large unit with the same SEER2 figure are not equally efficient in absolute energy use, because the larger unit moves more heat. A buyer comparing two North American models should therefore compare SEER2 figures for the same capacity step, and should ask for the test documents if a regulatory filing or a customer guarantee depends on the figure. The air handler unit's title also carries a SEER2 17–19 description, but its specification table does not carry a SEER2 row, so that title figure should be treated as title context and confirmed in the inquiry rather than quoted as a specification.
SEER2 also has a heating counterpart in North America, HSPF, which does not appear in the listings on this site. A buyer who needs a heating efficiency figure for a North American model should ask for it explicitly, rather than assuming a SEER2 cooling figure says anything about heating performance. Cooling and heating efficiency are different measurements, and a model can be strong in one and ordinary in the other.
ERP and A+++ in this range
In this range, the European labelling language appears for the Origin A+++ R32 model, the Premium A+++ R32 model and the Aeolus split heat pump, described with ERP A+++. A+++ is the top label class in the labelling scale as presented in these listings, and it signals high seasonal efficiency within the European system. As with SEER2, the label should be used to compare European models with each other, for the same capacity step and the same product type, rather than to rank a European model against a North American one. The label also does not state an absolute energy consumption figure: a large A+++ unit still uses more energy than a small lower-labelled unit, because it moves more heat. A buyer who needs an annual consumption estimate should ask for the calculation behind it, including the climate zone and usage pattern assumed, because the label alone does not provide that estimate.
The ERP framework also covers more than labelling: it sets minimum efficiency requirements and information requirements for products placed on the European market. A buyer importing into Europe should therefore check not just the label class but the full ERP information for the model, and should confirm that the documents are available on request before shipment. Certificates are available upon request on this site, and the ERP documents for a European model should be requested in the same inquiry as the model list.
Rated EER and COP: a third kind of figure
Alongside the seasonal labels, several model pages list rated EER and COP figures — efficiency at one set of rating conditions, rather than across a season. 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 dramatically different only because it uses the North American unit convention; converted to watts per watt it sits in the same range as the others, and the difference is a unit difference, not a performance difference. Rated figures and seasonal figures answer different questions — rated figures describe one operating point, seasonal figures describe a season — and they should not be ranked against each other. A buyer should use rated figures to check electrical load and rated performance, and seasonal labels to compare seasonal efficiency within one system, and should keep those uses apart.