Heater costs 2 mpg?

[Shinjitsu]

Import tuner did some testing in their Fact or Fiction tech section back in August 2010. They dynoed a Subaru Impreza to find the power loss due to parasitic drag from the engine accessories. First getting a baseline, then with all the electronics on, then with the A/C going. The electronics (lights, radio, fan, etc) showed about a 2% loss in power. The A/C was about 10%. The URL is below. This was, to me, one of the best sections of the magazine, it's a real shame they've stopped doing it.

Fact Or Fiction: Do Electrical Systems Decrease Power? - Import Tuner Magazine