Editing Block heater (section)

==Usage==
[[File:Standheizung-Schweden.jpg|thumb|A parked car plugged in to an electrical outlet to power the block heater]]
Block heaters are frequently used in regions with cold winters such as the northern United States, Canada, Russia and Scandinavia. In some countries where block heaters are commonly used, carparks are sometimes fitted with electrical outlets for powering the block heaters.

Testing in the 1970s of warm-up times for block heaters found little benefit in operating a block heater for more than four hours prior to starting a vehicle.<ref>{{cite journal |last1=Wiens |first1=E.H. |title=Automotive Engine Heaters |journal=Canadian Agricultural Engineering |date=June 1972 |pages=15–20 |url=http://www.csbe-scgab.ca/docs/journal/14/14_1_15_ocr.pdf |access-date=30 August 2019}}</ref> It was found that coolant temperature increased by almost {{convert|20|C-change|F-change|0|}} during the first four hours, regardless of the initial temperature. Four tests were run at ambient temperatures ranging from {{convert|-29|to|-11|C|F|0|abbr=on}}; continued use of the heater for up to two hours more only further increased the temperature by up to {{convert|3|C-change|F-change|0|abbr=on}}. Engine oil temperature was found to increase over these periods by just {{convert|5|C-change|F-change|0|abbr=on}}.<ref>{{cite web |title=Car warmers, block heaters and energy controls |url=http://www.hydro.mb.ca/your_home/home_comfort/block_heaters.pdf |website=www.hydro.mb.ca |archive-url=https://web.archive.org/web/20110927134325/http://www.hydro.mb.ca/your_home/home_comfort/block_heaters.pdf |archive-date=27 September 2011}}</ref>