Hi and welcome!
There are 2 heating options in your trailer. The heat pump, "HP" on the thermostat mode, is almost as noisy as the ac. This is a function of the ac unit that uses electricity to heat the air. The furnace, "fur" on the thermostat, is not as loud. You may have to adjust your vents to achieve a uniform temperature while using the heat pump. I don't know if you can adjust the vents for the furnace ( those are the vents that are low in your trailer).