Noise test standards for household appliances are mainly intended to evaluate and control the sound levels generated by appliances during use to ensure that they do not adversely affect the comfort and health of users. In China, noise testing for household appliances follows the national standard GB/T 4214 series, which covers noise test methods and limits for a variety of household appliances. Here are a few specific examples:

GB/T 4214.1 - This is the basic standard for noise test methods for household and similar electrical appliances, providing general principles and technical requirements for noise measurement.

GB/T 4214.2 - Noise test methods specifically for washing machines and dehydrators.

GB/T 4214.8 - Special attention is paid to noise testing of electric stoves, ovens, grills, microwave ovens and their combination appliances.

GB/T 4214.9 - Noise test methods for electric fans.

GB/T 4214.10 - Noise test methods for air conditioners.
These standards usually specify the test conditions, such as the test environment (whether in an anechoic chamber or a semi-anechoic chamber), the test distance, the layout of the test points, the requirements for background noise, the type of measuring instrument (usually a type 1 or type 2 sound level meter), and the calculation and expression of data.

Based on previous information, the following are some specific noise limits for common electrical appliances, for example:

The maximum limit for washing noise of a washing machine is 62 decibels (dB), and the limit for dehydration noise is 72dB.
For refrigerators with a volume of less than 250 liters, the noise limit is 45dB to 47dB; the limit for refrigerators with a volume of more than 250 liters is 48dB to 55dB.
The noise of the indoor unit of an air conditioner with a cooling capacity of less than 2000W should not be greater than 45dB, and the outdoor unit should not be greater than 55dB; for split air conditioners with a cooling capacity of 2500W to 4500W, the indoor unit noise should not be greater than 48dB, and the outdoor unit should not be greater than 58dB.
Fans with different fan blade specifications have different noise limits, ranging from 59dB to 73dB.

Please note that these limits may change with technological advances and standard updates, so the latest national standard version should be referred to in actual application. If noise testing of household appliances is required, it is recommended to contact a professional testing agency or consult the latest national standard documents to obtain the most accurate information.