Take a look at the rbe node (one of the defaults). Will only send the message if the value has changed.
@Darbos There’s an addon for Hassio
https://community.home-assistant.io/t/repository-notoriousbdg-add-ons-node-red-ha-bridge-and-gogs/
Otherwise it’s in the Debian repositories etc. You need to install the additional integration for Home Assistant. Detailed info - http://diyfuturism.com/hass-and-nodered-smarthome