Hello All:
Here are some pictures of the pre-heater unit. I took these at an auto show in Switzerland last year. The pre-heater is manufactured for VW by Webasto, who also sell it as a stand-alone retrofit kit. It is very expensive - about USD 900 if you order it as a factory option on your Golf or Jetta, and about USD 1,400 if you purchase it as an aftermarket retrofit kit.
When installed at the VW factory as part of the OEM build of the car, it is located in the front left wheelwell area, in the same place as the two horns are located.
I spent some time talking to the manager of Webasto in Switzerland, who told me that the market for these is pretty much confined to people who live in
REALLY cold areas - for example, in mountain villages in the Alps, or people who live in Northern Norway, Sweden, or Finland. It seems that this is a useful gadget to have if you are expecting outside air temperatures of -20°C or less, and you don't have access to indoor storage for your car, or an electrical outlet to operate a block, cabin, or coolant recirculating heater.
Most people buy the unit as a convenience item in order to avoid having to scrape ice and snow off the windows in the morning. The unit is hooked into the controls for the heater fan circuit, once the coolant is warm enough, it starts to circulate through the engine and heater box, and the heater fan comes on at the low setting and circulates it through the cabin.
I had a look at it, then dismissed the idea of retrofitting it. Perhaps if I lived in Northern Quebec or Alberta, and did not have a garage, it might be attractive.
The pre-heater can be ordered in either a diesel model or a gasoline model, meaning, it will burn either fuel. It consumes about half a litre an hour of fuel - not really much, because you normally program it to come on about 2 to 3 hours before you plan to use the car. It draws electricity from the battery, but this is not a problem – what little bit the heater draws over a few hours to run the fan (and itself) is about what is saved in the starting cycle because the engine is already warm. So it’s a washout.
On the OEM installations, the heater is controlled through the display system of the radio (the high-end radio with the navigation system). If you also order an integrated phone system with your VW, it is possible to phone the car, press a few buttons on your phone, and either turn the heater on or program a start time from a remote location. If it is installed as an aftermarket item, you get a little remote control like the door unlocking device to control it.
My ‘two cents’ opinion: It's about the same price as an OEM xenon retrofit. Unless I lived in a really cold place and had no garage and no electricity available, I'd spend my money on OEM xenons first. Most people who live in really cold places in North America have access to an electrical outlet for a plug-in heater (cabin, block, coolant recirculation, whatever). This is not usually the case in Europe, hence, the market for these ‘standalone’ pre-heaters.
Here's some pictures:
Webasto Heater on display stand at auto show
Blue tubes are coolant flow, silver tube (corrugated) is combustion exhaust, short silver tube with black rubber end is the air intake (combustion supply), small green can contains fuel.
Cutaway photo showing inside of heater
Electronics inside heater