More heat needed in garage. Ideas?

KJK66 I was at Dove and it was cold. Nothing out of ordinary though. I had my set to 66 and it was on most of the night. Mine has a 4" register but the inlet to the register is 2" at most. I wish my heater was under the fridge but its not or I would do that mod you suggested. My heater is under stairs to bedroom. Pretty far away. Batteries started at 12.6v and in morning they were 12.3v which is actually pretty good for the amount the thing was on. I just have to get under the belly pan and see if I can add or tee off main and add another pipe to rear. You can for sure feel temp diffence from main room to garage. This where our dinette is so I want it toasty myself eating dinner. Off topic man we need some rain. Thanks for ideas everyone.