This post is older than a year. Consider some information might not be accurate anymore.
Another usage of the Let’s Encrypt certificates, is to use it for Postfix TLS. On Debian 8 edit the /etc/postfix/main.cf.
# TLS parameters
#smtpd_tls_cert_file=/etc/ssl/certs/ssl-cert-snakeoil.pem
#smtpd_tls_key_file=/etc/ssl/private/ssl-cert-snakeoil.key
smtpd_tls_cert_file=/etc/letsencrypt/live/cinhtau.net/cert.pem
smtpd_tls_key_file=/etc/letsencrypt/live/cinhtau.net/privkey.pem
smtpd_use_tls=yes
smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache
Replace cinhtau.net with your domain name.
