What should be the maximum response time to customer emails in order to maintain a good customer relationship?

Maximum24 hrs if in case you are travelling or busy , incase of travelling direct it to some colleague so the issue is taken care. Normally in5-6 hours or same day a response should be sent back or based on urgency of matter.

 

Immediate acknowledge and maximum48 hours for response.

Immediat acknowledgment maintains and improves customer relations. Response time will vary based on the customer's issues and the availability of resources, but a target time should be defined in the acknlowledgment message.

You need to response ASAP. If you don`t  have solution right away, make a quick reply. You need to say that you  working on the topic and will reply as soon as you get solution or information. Customer will be calm knowing that you are there for him/her and you are trying to deal with subject. 

A standard response time should not exceede than hours. A customer can understand process time to get his query answered but the time can vary depending on the urgency and requirement of the customer. Setting a standard response time can leave an expression of professionalism on customer.