ANNEX IV — Method for calculating the Energy Efficiency Index

1.CLASSIFICATION OF HOUSEHOLD REFRIGERATING APPLIANCES

Household refrigerating appliances are classified in categories as in Table 1. Each category is defined by the specific compartment composition as specified in Table 2 and is independent of the number of doors and/or drawers.

Table 1

Household refrigerating appliances categories

Category	Designation
1	Refrigerator with one or more fresh-food storage compartments
2	Refrigerator-cellar, cellar and wine storage appliances
3	Refrigerator-chiller and refrigerator with a 0-star compartment
4	Refrigerator with a 1-star compartment
5	Refrigerator with a 2-star compartment
6	Refrigerator with a 3-star compartment
7	Refrigerator-freezer
8	Upright freezer
9	Chest freezer
10	Multi-use and other refrigerating appliances

Household refrigerating appliances that cannot be classified in categories 1 to 9 because of compartment temperature are classified in Category 10.

Table 2

Household refrigerating appliance classification and relevant compartment composition

Nominal temperature (for the EEI) (°C)	Design T	+ 12	+ 12	+ 5	0	0	– 6	– 12	– 18	– 18	Category (number)
Compartment types	Other	Wine storage	Cellar	Fresh food storage	Chill	0-star/Ice making	1-star	2-star	3-star	4-star
Appliance Category	Compartments composition
REFRIGERATOR WITH ONE OR MORE FRESH-FOOD STORAGE COMPARTMENTS	N	N	N	Y	N	N	N	N	N	N	1
REFRIGERATOR-CELLAR, CELLAR AND WINE STORAGE APPLIANCE	O	O	O	Y	N	N	N	N	N	N	2
	O	O	Y	N	N	N	N	N	N	N
	N	Y	N	N	N	N	N	N	N	N
REFRIGERATOR-CHILLER AND REFRIGERATOR WITH A 0-STAR COMPARTMENT	O	O	O	Y	Y	O	N	N	N	N	3
	O	O	O	Y	O	Y	N	N	N	N
REFRIGERATOR WITH A 1-STAR COMPARTMENT	O	O	O	Y	O	O	Y	N	N	N	4
REFRIGERATOR WITH A 2-STAR COMPARTMENT	O	O	O	Y	O	O	O	Y	N	N	5
REFRIGERATOR WITH A 3-STAR COMPARTMENT	O	O	O	Y	O	O	O	O	Y	N	6
REFRIGERATOR-FREEZER	O	O	O	Y	O	O	O	O	O	Y	7
UPRIGHT FREEZER	N	N	N	N	N	N	N	O	Y(1)	Y	8
CHEST FREEZER	N	N	N	N	N	N	N	O	N	Y	9
MULTI-USE AND OTHER APPLIANCES	O	O	O	O	O	O	O	O	O	O	10

Household refrigerating appliances are classified in one or more climate classes as shown in Table 3

Table 3

Climate classes

Class	Symbol	Ambient average temperature °C
Extended temperate	SN	+ 10 to + 32
Temperate	N	+ 16 to + 32
Subtropical	ST	+ 16 to + 38
Tropical	T	+ 16 to + 43

The refrigerating appliance shall be capable of maintaining the required storage temperatures in the different compartments simultaneously and within the permitted temperature deviations (during the defrost cycle) as defined in Table 4 for the different types of household refrigerating appliances and for the appropriate climate classes.

Multi-use appliances and/or compartments shall be capable of maintaining the required storage temperatures of the different compartment types where these temperatures can be set by the end-user according to the manufacturer’s instructions.

Table 4

Storage temperatures

Storage temperatures (°C)
Other compartment	Wine storage compartment	Cellar compartment	Fresh-food storage compartment	Chill compartment	One-star compartment	Two-star compartment/section	Food freezer and three-star compartment/cabinet
tom	twma	tcm	t1m, t2m, t3m, tma	tcc	t*	t**	t***
> + 14	+ 5 ≤ twma ≤ + 20	+ 8 ≤ tcm ≤ + 14	0 ≤ t1m, t2m, t3m ≤ + 8; tma ≤ + 4	– 2 ≤ tcc ≤ + 3	≤ – 6	≤ – 12(2)	≤ – 18(3)

2.CALCULATION OF THE EQUIVALENT VOLUME

The equivalent volume of a household refrigerating appliance is the sum of the equivalent volumes of all compartments. It is calculated in litres and rounded to the nearest integer as:

$${V _{eq}} = {\left [\sum V _{c} \times {\frac{25 - T _{c}}{20}} \times \mathrm{FF} _{c}\right ] \times \mathrm{CC} \times \mathrm{BI}}$$

where:

• n is the number of compartments
• V_c is the storage volume of the compartment(s)
• T_c is the nominal temperature of the compartment(s) as set out in Table 2
• \({\frac{25 - T _{c}}{20}}\) is the thermodynamic factor as set in Table 5
• FF_c, CC and BI are volume correction factors as set out in Table 6.

The thermodynamic correction factor \({\frac{25 - T _{c}}{20}}\) is the temperature difference between the nominal temperature of a compartment T_c (defined in Table 2) and the ambient temperature under standard test conditions at + 25 °C, expressed as a ratio of the same difference for a fresh-food compartment at + 5 °C.

The thermodynamic factors for the compartments described in Annex I, points (i) to (p), are set out in Table 5.

Notes:

1. for multi-use compartments, the thermodynamic factor is determined by the nominal temperature as given in Table 2 of the coldest compartment type capable of being set by the end-user and maintained continuously according to the manufacturer’s instructions;

1. for any two-star section (within a freezer) the thermodynamic factor is determined at T_c = – 12 °C;

1. for other compartments the thermodynamic factor is determined by the coldest design temperature capable of being set by the end-user and maintained continuously according to the manufacturer’s instructions.

Notes:

1. FF is the volume correction factor for frost-free compartments.

1. CC is the volume correction factor for a given climate class. If a refrigerating appliance is classified in more than one climate class, the climate class with the highest correction factor is used for the calculation of the equivalent volume.

1. BI is the volume correction factor for built-in appliances.

3.CALCULATION OF THE ENERGY EFFICIENCY INDEX

For the calculation of the Energy Efficiency Index (EEI), of a household refrigerating appliance model, the Annual Energy Consumption of the household refrigerating appliance is compared to its Standard Annual Energy Consumption.

1. The Energy Efficiency Index (EEI) is calculated and rounded to the first decimal place, as:
   $${\mathrm{EEI}} = {{\frac{\mathrm{AE} _{c}}{\mathrm{SAE} _{c}}} \times 100}$$

   where:

   • AEC = Annual Energy Consumption of the household refrigerating appliance
   • SAEC = Standard Annual Energy Consumption of the household refrigerating appliance.
2. The Annual Energy Consumption (AE_C) is calculated in kWh/year and rounded to two decimal places, as:

   AE_c = E_24h × 365

   where:

   • E_24h is the energy consumption of the household refrigerating appliance in kWh/24h and rounded to three decimal places.
3. The Standard Annual Energy Consumption (SAE_C) is calculated in kWh/year and rounded to two decimal places, as:

   SAE_c = V_eq × M + N + CH

   where:

   • V_eq is the equivalent volume of the household refrigerating appliance
   • CH is equal to 50 kWh/year for household refrigerating appliances with a chill compartment with a storage volume of at least 15 litres
   • the M and N values are given in Table 7 for each household refrigerating appliance category.

Table 7

M and N values by household refrigerating appliance category

Category	M	N
1	0,233	245
2	0,233	245
3	0,233	245
4	0,643	191
5	0,450	245
6	0,777	303
7	0,777	303
8	0,539	315
9	0,472	286
10	(4)	(5)