# Home heating question: testing for common wire at thermostat

**URL:** <https://boards.straightdope.com/t/home-heating-question-testing-for-common-wire-at-thermostat/743285>\
**Category:** Factual Questions\
**Created:** [January 15, 2016, 10:26pm UTC](https://boards.straightdope.com/t/home-heating-question-testing-for-common-wire-at-thermostat/743285 "2016-01-15T22:26:59Z")\
**Posts on this page:** 1\
**Page:** 2

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**Author:** ![arseNal](https://avatars.discourse-cdn.com/v4/letter/a/ecae2f/32.png) [@arseNal](https://boards.straightdope.com/u/arseNal)\
**Post date:** [January 19, 2016, 4:37pm UTC](https://boards.straightdope.com/t/home-heating-question-testing-for-common-wire-at-thermostat/743285/21 "2016-01-19T16:37:32Z")

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> [@Hail\_Ants](#):
>
> Yes, that’s exactly what I did and it worked perfectly. AC power is power, it makes absolutely no difference if it originates from the furnace, the WiFi thermostat simply needs a power source for its LCD display and WiFi functionality.
> 
> [Here’s a video describing how to do it.](https://www.youtube.com/watch?v=8a_f2_iAW1U)

Thanks, I might try this if it proves too annoying to get the real thing from the furnace.

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