The heater is out at the trailer in the storage lot, so I don't have the model. The heater a cube about 6" on a side. It cost me about $60 if I remember right. It has a thermostat and keeps the temperature in the trailer quite even. I put it on the floor by the door.
Every sort of electrical heat is equal in efficiency by definition. The good things about the Pelonis are that it is much quieter than running the AC heat strip and the heat is at floor level which makes the interior a lot more comfortable. Also, it can be moved around to blow into the bathroom, for instance or towards where you are sitting.
It is also quite safe. There is a tilt switch which turns it off if not sitting bolt upright and an overtemp switch that shuts it off if the fan is blocked in any way.
John W. Irwin
2018 Interstate GT, "Sabre-Dog V"