Requirements on Minimum Energy Performance Standard and Energy 
Efficiency Rating Labelling and Inspection for Electric Storage Tank Water 
Heaters  (Amendment Draft)  
Subject : Amendment to the Requirements on Minimum Energy Performance 
Standard and Energy Eff iciency Rating Labelling and Inspection for Electric 
Storage Tank Water Heaters  
Basis: Paragraph 4, Article 14 of the Energy Management Act  
Announcement ： 
1. Application Scop e：The Electric Storage Tank Water Heaters  stated  in this 
Announcement refer to  those meeting the definition of Electric Storage Tank Water 
Heaters  as defined in CNS 1 1010 , and promulgated by the Bureau of Standards, 
Metrology and Inspecti on (BSMI) of the Ministry of Economic Affairs (MOEA) as 
products requiring inspection before marketing.  
2. Test Method ：In accordance with CNS 11010 . 
3. The testing and calculation  of Electric Storage Tank Water Heaters  shall comply with 
the following requirement s： 
(1) The Capacity of inner tank of Electric Storage Tank Water Heaters  shall be tested 
in accordance with CNS 11010 .The measured value of Capacity of inner tank 
rounded off to the first decimal place and the allowance between the rated 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 . 
(2) The Standardized  Standby Loss of every  24 hours (Est,24) of Electric Storage Tank 
Water Heaters  shall be t ested in accordance with CNS 11010 .The measured value 
of Est,24 rounded off to the fourth  decimal place shall not be higher  than the 
Minimum Energy Performance Standard (MEPS) of Electric Storage Tank Water 
Heaters  (see Table 1), and shall be less than or equal to 105% of the declared 
value of products.  
4. Labelling Scheme for Energy Performance and Energy Efficiency Rating  
(1) The minimum size of displayed label shall be : 120mm (height)   80mm  
(width).The samples and specifications are provided as follow : 
 
   
 
  
  
 
 
  
(2) The Energy Efficiency Rating Label shall include the information listed as below : 
(i)  Name of the product ( Electric Storage Tank Water Heaters ). 
(ii) Model number of the product . 
(iii) Rated capacity of inner tank  (Liters) . 
(iv) Standardized  Standby Loss of every  24 hours Est,24  (kWh/24 h ). 
(v) Energy Efficiency Rating classified in accordance with the “Energy 
Efficiency Rating Standards for Electric Storage Tank Water Heaters ” of Table 
2. 
(vi) Annual electricity consumption (kWh), which is calculated by  the 
Standardized  Standby Loss of every  24 h ours value (kW h/24 h ) × 365 
days/year . 
(vii) The year and the number of announcement of the applied Energy Efficiency 
Rating Standards for Electric Storage Tank Water Heaters . 
(viii)  Registration number of the pr oduct.   (ix) Other texts designated by the Central Competent Authority.  
(3) The display or post of the label  
While displaying or marketing Electric Storage Tank Water Heaters , the firms 
shall display, post or disclose the Energy Efficiency Rating Label on the f ront of 
the products , and shall not hide, destroy or adopt other means to render the 
label ling not recognizable by the consumers. While manufacturing or importing 
the products, the firms  shall display or attach the Energy Efficiency Rating Label 
in/on the  product instruction/manual or place the label in a prominent area on the 
front of the products . 
(4) Energy efficiency rating  
The products shall be classified for Energy Efficiency Rating based on the labeled 
Est,24, and shall be labeled on the Energy Efficien cy Rating Label.  
(5) Market Inspection  
The Central Competent Authority may apply random inspection per annum while 
applying the inspection of the Energy Efficiency Rating Labelling. The samples 
for random inspection shall be designated by the Central Competent  Authority, 
and shall be delivered by the firms to the designated inspection laboratories for 
testing within the required term. The amount of samples for random inspection 
shall be decided based on the total amount of products marketed by the 
manufacturers  or the importers of the previous year. In principle, one unit shall be 
sampled for inspection for 2,500 units. If the total amount is less than 2,500 units, 
one unit shall still be sampled for inspection. Nonetheless, the Central Competent 
Authority may a djust the amount of samples and the sampling ratio for random 
inspection according to actual needs.  
 
Table 1 MEPS for Electric Storage Tank Water Heaters  
Rated Capacity of 
inner tank , V  
(Liters , L) The Standardized  Standby Loss of every  24 hours 
Est,24 (kWh/24  h) 
Less than 60 liters  0.1105 + 0.0470  × V2/3 
Above 60 liters  0.17 + 0.0434 × V2/3 
 
 
   Table 2 Energy Efficiency Rating Standards for Electric Storage Tank Water Heaters  
Energy 
Efficiency 
Rating  The Standardized  Standby Loss of every  24 hours, Est,24 (kWh /24 h) 
Rated Capacity of inner tank ,  
V＜60 liters Rated Capacity of inner tank ,  
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+0.03 32×V2/3 
Class 3 0.0845+0.0359×V2/3＜ 
Est,24≦ 0.0932+0.0396×V2/3 0.13+0.0332×V2/3＜ 
Est,24≦ 0.1433+0.0366×V2/3 
Class 4 0.0932+0.0396×V2/3＜ 
Est,24≦ 0.1018+0.0433×V2/3 0.1433+0.0366×V2/3＜ 
Est,24≦ 0.1567+0.0400 ×V2/3 
Class 5 0.1018+0.0433×V2/3＜ 
Est,24≦0.1105+ 0.0470×V2/3 0.1567+0.0400×V2/3＜ 
Est,24≦0.17+0.0434×V2/3