COP & EER
COP – the ratio that measures the energy efficiency of the HEATING performance.
EER – the ratio that measure the energy efficiency of the COOLING performance.
Both ratios are determined by the amount of heating and cooling generated by the air conditioning compared with the 1kW of electricity it consumes.
So, an air conditioner that generates 3.6kW of heating when using 1kW is say to have a COP of 3.6. Therefore the air conditioning that generates most heating out of 1kW is the most efficient, hence the higher the COP the more efficient is the air conditioning.
Likewise, an air conditioner that generates 3.6kW of cooling when using 1kW is say to have an EER of 3.6.
How to compare products
Compare the COP and EER ratios of products with the same output to determine which are more energy efficient.
For example, compare 2 air conditioning unit both with 3.5kW (12000 BTU) power output, the one with the higher COP and EER is more energy efficient.