Technical Electric Heaters are there any that do a good job?

I have seen some early VW with gasoline heaters. It sounds terrifying to me but they seem to have been pretty reliable as VW used them in several models sold in colder climates over the years.

 

They were pretty common in old Fords, too. You still see them at swap meets from time to time, and some folks still like the under carb plates as a vacuum source.

You're right, though; I don't know what scares me most, a gas heater or one that goes on the exhaust manifold.

 

I'd suggest something like this:

https://www.hipnosi.com/product-p-444895.html

 

I'm thinking that is right on the line of what the Frenchtown flyer said he has. Not much for defrosting the windshield unless you rig a defroster on it though.
This on on Amazon is only about 4 inches wider but isn't as tall if I read it right. Amazon.com: Upgraded of 12V Universal Auxiliary Heater Underdash Heat with Speed Switch for Car or Truck Minivans Excavators Harvesters 4 ports US Stock : Automotive

 

I've got a 12 volt plug into the lighter electric blanket that will keep one's legs reasonably warm in a car with no or a suspect heater or a back seat that doesn't get heat to it well. It works in my drafty F250.

 

Electric resistance heat consumes watts. They simply aren't feasible at a mere 12 volts for space heat.

To put this into perspective, to get the same BTU output of the above heater as resistive heat at 12 volts would require almost 300 amps! An electric heater that draws 30 amps @12V would produce a miniscule 600 BTUs (or just 5% of the above heater), which might be enough to possibly defrost a windshield depending on ambient temps.

 

This is the Summit unit.

 

Our electrician has an transit 250 Ford van and it get 160 miles to a charge and if he runs the heat or AC it drops to half. He hates it