1 Amendment  to the  Minimum Energy Performance Standard  and Energy 
Efficiency Rating  Labelling and Inspection  of Electric Storage Tank Water 
Heaters (Draft)  
 
Subject：Announcing the Amendment to the Minimum Energy Performance 
Standard  and Energy Efficiency Rati ng Labelling and Inspection  of Electric 
Storage Tank Water Heaters  
Legal  Basis： Paragraph 4, Article 14 of the Energy Management Act  
Announcement ： 
I. Scope  of the Product : The electric storage tank water heaters  denoted in this 
announcement are those meeting the definition in CNS 1 1010 , and 
promulgated by the Bureau of Standards, Metrology and Inspection (BSMI) 
of the Ministry of Economic Affairs (MOEA) as products requiring 
inspection.  
 
II. Test Method :  CNS 1 1010  
III. Capacity  of the Inner Tank: The allowance between  the marked and tested 
values for capacity of the inner tank shall be ±3% for inner tanks with the volume 
below or equal to 100L, and ±2% for those with the volume above 100L.  
IV. Minimum Energy Performance Standard  (MEPS)： The normalized standby 
loss by Electric Storage Tank Water in 24 hours (Est, 24 hereafter)  shall not  
exceed  the value specified in the Table 1 ( the minimum energy performance 
standard  requirements  for electric storage tank water heaters)  and shall  not 
exceed  105% of their rated value . Both criteria must be met.  
V. Labelling Scheme for Energy Efficiency Rating : 
(I) Minimum  size of displayed label ：120mm long, 80mm wide , its samples and 
specifications shown as follow :  2 
 
  
  
 
  
(II) Content of energy efficiency rating label: 
1. Product name  (Electric storage tank water heater ) 
2. Product model number  
3. Inner tank  capacity  (Liters) 
4. Normalized standing loss per 24 h value  (kWh) 
5. Energy efficiency rating  per Table 2 (Energy efficiency rating standard 
requirements for electric  storage tank water heaters)  
6. Annual electricity consumption (kWh)  (Calculation formula:  the 
Normalized standing loss  per 24 h  value  (kWh) × 365 days /year ) 
7. The year and the number of the announcement  of the “ Criteria for 
Energy Efficiency Rating  of Electri c Storage Tank Water Heaters ” the 
rating determination  is based on.  
8. Registration number   3 9. Other text as designated by the Central Competent Authority  
(III) Display the label : 
While manufacturing or importing the products,  the dealer shall display or 
attach the en ergy efficiency label in /on the product instruction/manual,  or 
place the label in a prominent area in front of the products.  While displaying 
or marketing the products, the dealer shall  display or post the energy 
efficiency rating label in front of the pro ducts, and shall  not hide, destroy or 
adopt other means to the label not recognizable by the  consumers.   
(IV) Energy efficiency rating :  
The products shall be classified for energy efficiency rating  based on the 
Normalized Standing Loss per 24 h  value  shown in the following table  2 
and shall be marked onto the energy efficiency labeling.  
(V) Post- Market Inspection :  
The Central Competent Authority may carry out annual energy efficiency 
spot check . The samples to be spot checked shall be designated by the 
Central Competent Authoirty . The supplier shall submit subject products to 
given labs for testing in given period.  
The sampling quantity shall be determined by the following rule: every 
2500  units made or imported last year shall sample one unit for spot check, 
models of population less than 2500 shall sample one as well. The central 
competent authority may adjust test model and quality as required.  
The Central Competent Authority shall publicize the said information in the 
Management System according to the Consumer Protection Act  
 
Table 1 the minimum energy performance standard  requirements  for electric storage 
tank water heaters  
Inner tank  capacity V  
(L) MEPS for Normalized 
Standing Loss per 24h, 
Est,24 
(kWh)  
less than 60 liters  0.1235+0.0525×V2/3  
60 liters and above  0.19+0.0485×V2/3  
Note: V refer to the rated capacity of the inner tank round off to the first decimal  
place   4 Table 2 Energy  efficiency rating  standard  requirements  for electric storage tank 
water heaters  
Energy 
Efficiency 
Rating  Normalized Standing Loss per 24h, Est,24 (kWh)  
Inner tank  capacity V ＜ 60 
liters Inner tank  capacity V ≧ 60 
liters 
Class 1 Est,24≦0.0715+0.0304×V2/3 Est,24≦0.11+0.0281×V2/3 
Class 2 0.0715+0.0304×V2/3＜Est,24
≦ 0.0845+0.0359×V2/3 0.11+0.0281×V2/3＜Est,24≦ 
0.13+0.0332×V2/3 
Class 3 0.0845+0.0359×V2/3＜Est,24
≦ 0.0975+0.0415×V2/3 0.13+0.0332×V2/3＜Est,24≦ 
0.15+0.0383×V2/3 
Class 4 0.0975+0.0415×V2/3＜Est,24
≦ 0.1105+0.0470×V2/3 0.15+0.0383×V2/3＜Est,24≦ 
0.17+0.0434×V2/3 
Class 5 0.1105+0.0470×V2/3＜Est,24
≦0.1235+0.0525×V2/3 0.17+0.0434×V2/3＜Est,24≦
0.19+0.0485×V2/3