It makes a MASSIVE difference. It won’t change the pump clicking, but definitely will make the heater quieter on the exhaust.
My lithium batter is installed in the box of the truck as the heater is not the only thing it powers. Before getting a Planar gasoline heater myself, my diesel heater was installed in a box and exposed to the elements.
You can check out my two iterations in my build page here:
I haven’t fully field tested the Autotherm (now Planar) yet but bench tests have been positive.
Hope that helps. There are links in my build as well to details on the diesel heater guru on YouTube. John McK 47 , dudes a legend and an Ausi so it’s a good watch 