Ebay Universal Car Heater 12 volts

This a quick look at a 4 port universal car heater that I got from ebay, to fit into a vehicle that never had a heater fitted as standard. It's a bit shonky but didn't cost a lot so I'm not too worried. There is a slight issue in that the main tubes that pass through the matrix is the wrong size tubing and doesn't give up its heat very readily so it cools down very quickly and blows cold air if you turn the fan up to high speed, but takes the chill off the air at a quarter speed. I would imagine that all of these Chinese heaters are the same inside, so if you need a heater that will power a demister as well as heat the cabin, then maybe none of them would be good enough, and you might be better off finding a used small car heater on ebay, if you have the space to mount one.