Interesting question this.
It’s generally thought the best time to send a sales email is between 10.00am and 10.30am and between 1.00pm and 1.30pm Tuesday to Thursday.
Monday is out of the question. Too many other things to deal with. Friday, forget it. No-one is thinking about work on a Friday. In the UK the weekend starts on a Thursday night. The only time you can send a sales email on a Friday is if you work for a holiday firm or a brewery.
So Tuesday to Thursday seems like a good bet. 10.00am allows people to have checked their early morning emails, looked at Facebook, and written a tweet. 1.00pm and you’re catching them in a post-lunch good mood.
But wait. There are things that are beyond your control. How is your server set up? You may press send at 10.00am but your emails may take hours to filter through. Or how about different time zones? Are you in Europe and sending sales emails to the US or Australia? Your sales emails will probably arrive in the middle of the night.
The important thing is to test. And keep a record of the time your sales emails were opened or replied to. Find out what works. And do more of it.