What is seasonal efficiency (SEER)?
In 2013, a new method of rating energy efficiency came into effect under the EU’s Energy Related Products (ErP) Directive. The new seasonal energy efficiency ratio (SEER) was a welcome introduction, as it gives specifiers a much better indication of how efficient an air conditioner is when operating over an entire cooling or heating season.
Previously, a ‘nominal’ ratio for cooling (EER) was used, based on the system operating at full load in nominal conditions. Tests were based on an ambient temperature of 35° - which of course is rarely reached in the UK - and this often resulted in a significant gap between predicted performance and what was actually achieved.
Now, SEER takes into account a number of factors, which together provide a much more realistic view of energy efficiency in real life conditions. The performance of the equipment is now measured across different climate zones, at both partial and full capacity, in both auxiliary and stand-by modes and over different load requirements across the seasons. The lower the rating, the better – and most importantly, it’s a realistic measurement that brings us one step nearer to closing the performance gap.
For building owners, the new rating is resulting in significant savings: not only from the improved data but also from the resulting product development. Innovations such as variable refrigerant temperature have lead to increases in seasonal efficiency of up to 25%; with newer systems offering the flexibility to achieve top efficiency throughout the year, balanced with a quick reaction speed on the hottest day or at peak loads.
However, there’s no doubt that the SEER has added an element of complexity, particularly in larger applications where several technologies might serve the building. More detailed analysis is required to determine the overall SEER; and in cases such as these, a reputable manufacturer will be able to provide the support required to achieve the desired result.