Understanding SEER and SCOP

Aug 11, 2023

The energy efficiency of a number of HVAC systems is measured by SEER, which is the seasonal energy efficiency ratio for cooling mode, and SCOP, which is the seasonal coefficient of performance for heating mode. Eurovent Certita Certification (ECC) has been certifying the energy efficiency of HVAC products for 30 years, so know a thing or two about energy performance ratings. In this article we explore SEER and SCOP and why they are important.  


Why do we need SEER and SCOP?

A wide range of products are regulated to make sure they reach specific benchmarks when it comes to energy use. From heating and cooling systems, to computers and tumble dryers, energy consuming appliances are rated to help consumers make greener choices, and promote competition between manufacturers for the development of sustainable products.  

The European Commission's Ecodesign Directive (2005/32/EC), aims to reduce the impact on the environment of energy-related products (ErP). Products used for heating and cooling need to hit minimum energy efficiency requirements. SEER and SCOP offer realistic standardised measurements for the rating of cooling and heating efficiencies, to both comply with regulations and allow systems to be compared directly, using the same sets of data. 

What is the Seasonal Energy Efficiency Ratio (SEER)?

SEER measures the cooling efficiency of products such as chillers and air conditioning systems. It is an evolution of the Energy Efficiency Ratio (EER), which aims to give a truer reflection of day-to-day use of an appliance over a year. While EER gives efficiency at a set point, SEER takes into account that cooling demand will change throughout the year, and replicates seasonal use.  

How is a SEER rating calculated?

To measure the energy consumption of a unit, in cooling mode, through a typical cooling season, SEER uses a set indoor temperature, along with different outdoor temperatures and load capacities to simulate real life. The EN 14825 standard defines the test methodology. SEER is calculated at the following conditions: 

Air source: 

  Capacity    100%   74%   47%   21%
  Outdoor temperature   35o   30oC   25o   20o

Water source: 

  Capacity    100%   74%   47%    21% 
  Outdoor temperature    30oC   26o   22o   18o

The SEER rating is calculated by dividing the total cooling output in watts (or BTUs depending on country) at the different conditions, by the total electric energy used in watts. 

What is a good SEER rating?

The higher the SEER rating, the higher the maximum efficiency of the system. SEER offers a valuable and tangible figure that’s easy for everyone to understand, whatever their background and knowledge of HVAC. 

The below gives an example of SEER ratings for air-to-air products below 12kW: 

  Energy efficiency class    SEER
  A+++    SEER ≥ 8.50 
  A++    6.10 ≤ SEER < 8.50 
  A+    5.60 ≤ SEER < 6.10 
  A    5.10 ≤ SEER < 5.60 
  B   4.60 ≤ SEER < 5.10 
  C   4.10 ≤ SEER < 4.60 
  D   3.60 ≤ SEER < 4.10 
  E   3.10 ≤ SEER < 3.60 
  F   2.60 ≤ SEER < 3.10 
  G    SEER < 2.60 

What is Seasonal Coefficient of Performance (SCOP)?

SCOP is used for measuring heating efficiency in products such as heat pumps. It is an evolution of the Coefficient of Performance (COP) which aims to give a truer reflection of day-to-day use of a system over a year. While COP gives efficiency at a set point, SCOP takes into account that our heating requirements change. SCOP replicates seasonal use, and gives a maximum efficiency rating for the appliance, with the full system working at an optimum level.  

How is a SCOP rating calculated?

SCOP is calculated a little differently to SEER, as three European climates can be used to represent typical seasonal operating conditions. These include Strasbourg for an Average climate, Athens for a Warmer climate, and Helsinki for a Colder climate. Because the three climates experience very different winter temperatures, this helps the HVAC professional understand how the system will operate in the installed environment.  

The EN 14825 standard defines the test methodology. Energy efficiency is calculated on four predefined operating points, considering part-load conditions. SCOP is calculated by the EN14825 Average profile, with the Warmer profile and Colder profile voluntary options: 

Average profile: 

  Indoor temperature    20o   20o   20o   20o
  Part load ratio    88%    54%   35%   15%
  Outdoor temperature    -7o   2o   7o   12o

Warmer profile: 

  Indoor temperature    20oC   20oC   20oC
  Part load ratio    100%    64%    29% 
  Outdoor temperature    2o   7o   12o

Colder profile: 

  Indoor temperature    20o   20o   20o   20o   20o
  Part load ratio    82%    61%   37%   24%    11% 
  Outdoor temperature    -15o   -7o   2o   7o   12o

The SCOP rating is calculated by dividing the total heating output in kilowatt hours (kWh) at the different operating points, by the total electric energy used (also in kilowatt hours).  

What is a good SCOP rating?

Just like SEER, the higher the number, the higher the energy performance rating. You’ll notice the numbers for SCOP are not as high as SEER, this is because heating uses more energy than cooling and will not reach the same efficiencies. Those choosing systems that have a larger heating than cooling demand may therefore place precedence on the SCOP rating when working out what system will offer the best efficiencies overall.  

The below gives an example of SCOP ratings for air-to-air products below 12kW: 

  Energy efficiency class    SCOP 
  A+++   SCOP ≥ 5.10 
  A++    4.60 ≤ SCOP < 5.10 
  A+    4.00 ≤SCOP < 4.60 
  A    3.40 ≤ SCOP < 4.00 
  B    3.10 ≤ SCOP < 3.40 
  C    2.80 ≤ SCOP < 3.10 
  D    2.50 ≤ SCOP < 2.80 
  E    2.20 ≤ SCOP < 2.50 
  F    1.90 ≤ SCOP < 2.20
  G    SCOP < 1.90 

Will my system achieve the SEER and SCOP stated?

SEER and SCOP give a good indication of seasonal HVAC energy use over a typical year. However, a key thing to remember is that SEER and SCOP are measurements of a system performing at its peak. It’s highly unlikely any system will be performing optimally 100% of the time. 

System performance will depend on: 

  • Good design and professional installation of the entire system 
  • Regular maintenance 
  • The size of the building being conditioned and its energy efficiency 
  • The size of the system and its air handling capacity 
  • The amount of time the system is used daily 
  • The indoor temperature you prefer 
  • The outdoor air temperature. 

So while a well designed, installed and maintained HVAC system should work efficiently and to its best potential, energy efficiency can vary depending on a number of influences. None-the-less, SEER and SCOP can be very useful when comparing systems. 

Why should I choose a product with certified SEER and SCOP?

Manufacturers or distributors (if the product is imported), have to prove conformity with regulations such as Ecodesign. While there is legislation in place to ensure compliance, testing is essentially self-governed, which can inadvertently lead to variations in the quality and accuracy of testing, and therefore the results which guide product performance claims.  

Third-party certification removes the risk of variations between stated and real performance, and creates trust by providing transparent, independently verified product data. All ECC certification programmes have a common set of criteria for the rating of products, with all units going through exactly the same route and process to certification. 

Being able to trust energy performance is an important step in specifying products that work as expected. For the HVAC&R professional the added value of choosing a Eurovent certified product includes: 

  • Access to universally understood performance data  
  • The assurance that product data is accurate and has been impartially tested, to exacting standards, by an expert, independent third-party 
  • Assurance that systems will perform as expected, because they are designed on verified, real life performance 
  • A guarantee that products comply with regulations, standards and codes 
  • And a number of certified products have spare parts available for 10 years. Meaning they can be serviced for years to come. 

So if you need an energy efficient HVAC system, search our certified product directory today.