In the various brochures, press releases, and web pages about the 4GS, you might have seen references to the "high-intensity interior heater" that comes with Canadian models and US models with the cold weather package.

I didn't see any of those sources actually describe what it is, and it wasn't until I got a 2-day subscription to TechInfo and started looking at parts diagrams and specs that I clued in. In those it is referred to as a "PTC heater" or a "quick heater assembly", etc., and there are fuses for it (2x 50 amps). It's an electric heater!

With the cold weather in Toronto this week, I've been trying to pay attention to whether or not it does anything. It's subtle, but this morning there was definitely noticeable heat from the defroster vent within 60 seconds of starting the engine.

I know the GS isn't the only Lexus with this feature, and other manufacturers have it too, but they don't do a good job of explaining it (in my opinion) so thought maybe others might not realize they have this on their car.

 

I agree that they should go into a lot more detail on this option.
I ended up finding all of 1 website that explained it in more detail. And I believe it was a write-up from some local new station or magazine or something.

At first I mainly just wanted the heated steering wheel from the package but it was a little hard for me to want to buy the whole package just for one item. After I found out that it was basically an electric heater that could get my car heated quicker (instead of driving around 3 - 5 minutes waiting for the engine to heat up) I felt like the package was closer to being worth the price.

I ended up custom ordering just to get this option (and later for the power trunk).