We've hade a fairly cold winter this year in Finland. Even in the southern part of our country the temperature has occasionally been -25 deg Celsius. This has resulted in clearly reduced range and I found myself putting more clothes on when trying to minimize the need for the electric heating.
I finally decided to install a fuel burning auxiliary device to heat up the water in the heater loop.
This Eberspacher unit is located behind the frunk box:
It could burn ethanol which would be more sustainable. I use fuel oil (diesel) instead because I think it is safer.
The operating switch:
I can use this heater instead of eletric heating while driving and I don't have to lower the temperature anymore to save electricity.
I can even pre-heat the car using the connected drive app. The fuel heater takes a signal from the original water circulation pump. The electric heater also kicks in but the PTC resistor will soon turn down the power consumption when the auxiliary device heats up the water.
It seems that the electric range is now about 30% longer. Very happy