[Fr3AkAzOiD]

Going into work today I had the heater on and was getting far worse mpg then I was several days ago.
Temps had droped from being in the 60's and 70's to being in the 30's and 40's with a cold front that moved in causing my super awesome tank average of 58 mpg to plummet.

On my trip to work I have several flat stretches so I held the car at 45 mph to get a level mpg reading and then turn on the heat and my mpg would drop by 2 (4% loss).

Even though I did this test 20 times (16 of 20 lost 2 mpg, 4 of 20 lost 1 mpg) I know it's far from being a scientific set of A-B-A tests.

Frostbite is not sexy so I'll still be using the heater, I was just wondering if anyone else noticed lost fuel economy due to turning on their heater.