Emax is the maximum energy consumption, in kWh per year, that NOM-015-ENER-2018 allows a refrigerator or freezer. It depends on the type of appliance and its size. If the consumption measured in the laboratory exceeds it, the model cannot be certified with that consumption.
Calculating it takes three things: the appliance's class in Table 2 of the standard, its adjusted volume (AV, «VA» in the standard) and that class's formula. This guide walks through all three with a worked example.
What you need at hand
- DatasheetThe manufacturer's PDF or Excel file
- VolumesLiters of the refrigerator and the freezer
- What the appliance is likeDefrost, freezer position, ice maker
- ConsumptionMeasured or declared, in kWh/year
Find your class in Table 2
Table 2 sorts appliances into classes by how they are built: refrigerator only or refrigerator-freezer, the type of defrost, where the freezer sits, whether they have an ice maker and whether they are built-in. Each class has its own a and b coefficients.
Picking the wrong class changes the limit a lot. For the same adjusted volume of 300.2 L:
| Class | Appliance | a | b | Emax |
|---|---|---|---|---|
| 3 | Refrigerator-freezer, automatic defrost, top freezer, no ice maker | 0.285 | 233.7 | 319.3 kWh/year |
| 5 | Refrigerator-freezer, automatic defrost, bottom freezer, no ice maker | 0.312 | 317.0 | 410.7 kWh/year |
If you don't know your class, the validator asks you about the appliance, one question at a time, and narrows down the possible classes. Before using one, read its full description in the standard.
Calculate the adjusted volume
The adjusted volume is not the capacity the manufacturer prints: it gives the freezer more weight, because keeping it cold takes more energy. Datasheets almost never list it, but they do list the liters of each compartment. The validator calculates it like this:
With 221 L of refrigerator and 45 L of freezer: AV = 221 + 45 × 1.76 = 300.2 L.
Apply your class's formula
For class 3 in the example: Emax = 0.285 × 300.2 + 233.7 = 319.3 kWh/year. The model's consumption has to be at or below that value.
The validator does this calculation with your class and your AV, compares the result with the consumption on your datasheet and shows you a preview of the yellow label.
Frequently asked questions
Does the validator replace the laboratory?
No. It is a pre-validation: it tells you whether your product is on track before you pay for testing at an accredited laboratory. The official result is the laboratory's.
What if I don't know my refrigerator's class?
The validator has a helper that asks you, one question at a time, what the appliance is like (type, defrost, freezer position, ice maker) and narrows down the possible classes. Before using a class, read its description in the standard.
Why doesn't the datasheet list the AV?
The adjusted volume is a figure defined by the standard, not the capacity manufacturers print. If the datasheet lists the liters of each compartment, you can calculate it.
My consumption exceeds Emax. What are my options?
First check that the class and the AV are right: an error in either one changes the limit. If they are right, the model does not comply with that consumption; a consultant can go over the case with you.
Got your data?
Check your model with the validator, or ask a consultant to review your case.