With my 2011 and the Supplemental heater, I have never ever scraped a window and I have no garage. I live near Boston so I really really recommend it. It puts out about 1200W of heat which is not a lot in 110V ac terms but for a 12 volt system it is ALOT !! I just remote start my vehicle, even this morning when it was 5 degrees, and let it run 15 minutes.