Methodology presents the most energy efficient room air conditioners of Europe, up to a cooling capacity 12 kW. Topten lists mono- and multi-split room air conditioners,  single- and double-ducts.

Technical criteria

Air conditioners on meet different requirements regarding cooling and heating efficiency, based on the Labelling regulation No. 626/2011:
Air conditioner type Efficiency class cooling / heating function
Split ≤ 4kW A+++ / A++
Split > 4kW A++ / A+
Multi-split A++ / A+
Single ducts
A++ / A+ (no models at the moment)
Double ducts
A++ / A+ (no models at the moment)

Relevant values have to be provided by the producers. Producers who are not able to provide these values cannot claim to have their appliances displayed on All declarations can be verified by random measurements. Selection criteria can be changed any time to account for market developments: In spring 2015, selection criteria will be tightened - presumably to A+++/A+++ (< 4kW) and A++/A++ (other capacities).

Data sources

Order of presentation

Products are ranked according to their cooling efficiency index (SEER), at identical SEER according to their heating efficiency index SCOP. The order of presentation can be changed by clicking at the tables’ headings.


Air conditioner types

air conditioner indoor unit

Split air conditioner: indoor and outdoor unit

Split and multi-split
Split systems are fixedly installed and consist of at least two units. The outdoor unit contains compressor and condensor. The indoor unit contains the evaporator and can have different shapes and be placed on the ceiling, wall, floor or in a canal.
Multi-split systems combine two or more indoor units with an outdoor unit. The indoor units can be placed in different rooms.

Single-duct Double-duct

Single- und Double ducts (also: local air coolers, LACs)
LACs consist of one single unit. The whole unit is placed inside while the air is exchanged through one or two ducts leading through a window or wall opening. Because of the waste heat that is exhausted indoors and the required opening in the wall or window and insulation LACs are not efficient. LACs have their own Labelling scale - the efficiency of a class A single or double duct corresponds to a class F split air conditioner!

Brand, Indoor and outdoor unit model
Brand and names of the indoor and outdoor units.

Cooling / heating capacity (kW)
Maximum cooling / heating capacity in Kilowatts (kW), according to the Energy Label.

Electricity costs (EUR in 10 years)
Electricity costs in Euro that arise over 10 years of usage. Annual electricity consumption is based on the declaration of the Energy Label. The assumed electricity tariff is 0.2 EUR/kWh.

Cooling function efficiency (SEER)
The Seasonal Energy Efficiency Ratio (SEER) indicates the energy efficiency of the cooling function. It is calculated based on  several part load measurements according to the Energy Labelling regulation. The higher the SEER, the more efficient a product.

Heating function efficiency SCOP
The Seasonal Coefficient of Performance (SCOP) indicates the energy efficiency of the heating function. It is calculated analogically to the SEER. The higher the SCOP, the more efficient a product.

Energy efficiency class (cooling / heating)

Energy efficiency class of the cooling and heating functions according to the Labelling regulation from 2011. The Energy Label defines classes from A+++ to G. Split models with lower efficiency than class B (cooling)/ A (heating) are no longer permitted on the market since January 2014. 

Annual electricity consumption cooling /heating in kWh/year

Annual electricity consumption for cooling and heating, respectively, in kWh/year, according to the Energy Label. Assumed are 350 hours of cooling and 1400 hours of heating per year (average climate zone).

Sound power Indoor / Outdoor unit (detail view)

Sound power level of the indoor and outdoor unit for the cooling function in dB(A), according to the declaration on the Energy Label.

Refrigerant / GWP (detail view)

Name of the refrigerant and its Global Warming Potential (GWP in 100 years according to IPCC). Most common is R410A, a fluorinated refrigerant with a high GWP of 1975. Refrigerants with a GWP of 150 or lower can comply with the Ecodesign regulation with somewhat lower efficiency than products with traditional refrigerants. 

Size Indoor / Outdoor unit (detail view)

Size of the two units in mm (e.g. Width x Depth x Height)

Available in countries

This item displays the availability of models in European countries as far as known - according to producers’ declarations and national Topten sites. The country codes are according to ISO.



Standards and Labels


11/2016 Berger-Wey / Michel