Nominal vs. Seasonal efficiency
|Not only does the Eco-Design Directive systematically raise the minimum requirements with respect to environmental performance, the method used to measure this performance has also been changed to better reflect real-life conditions.
Previous measurements reflected so-called nominal efficiency, a measurement of performance at one fixed outdoor temperature and with equipment running at full power. Since a cooling or heating season involves a range of outdoor temperatures (not just the one nominal temperature in the rating) and equipment is often only running at partial load, this old rating did not properly reflect actual performance.
The new method, seasonal efficiency, measures heating and cooling performance across a range of outdoor temperatures and at various load conditions over an entire heating or cooling season. Moreover, auxiliary modes such as stand-by are also taken into account in the new seasonal efficiency ratings. Thus seasonal efficiency gives a much better representation of the real performance of an air conditioner, in real-life conditions, across an entire season.