I think it is worth finding out why your Surface Pro 3 could not handle your needs, including Outlook 2013 for email. My SP3 handles Outlook for 3 Exchange accounts and 6 other accounts (heavy traffic on the first three), an FTP client, and does my geophysical work, and often the receiver or transmitter of VPN or VNC sessions, without these problems.
I heard the fan only once, during a firmware update, months ago. And my SP3 sits in a thick rubber case (urban Armor Gear), so it has plenty opportunity to heat up.
Email involves mostly file management and communications tasks, not number crunching. Good workaround solutions to your original setup are proposed here, to your original setup, but you should not have these problems.