# Attic Fan on all night or AC on/off all night..which is cheaper?

**URL:** <https://boards.straightdope.com/t/attic-fan-on-all-night-or-ac-on-off-all-night-which-is-cheaper/263622>\
**Category:** Factual Questions\
**Created:** [September 8, 2004, 8:02am UTC](https://boards.straightdope.com/t/attic-fan-on-all-night-or-ac-on-off-all-night-which-is-cheaper/263622 "2004-09-08T08:02:38Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![dfqforever](https://avatars.discourse-cdn.com/v4/letter/d/439d5e/32.png) [@dfqforever](https://boards.straightdope.com/u/dfqforever)\
**Post date:** [September 8, 2004, 8:02am UTC](https://boards.straightdope.com/t/attic-fan-on-all-night-or-ac-on-off-all-night-which-is-cheaper/263622/1 "2004-09-08T08:02:38Z")

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This may seem obvious to some folks but I am an idiot in these matters. It’s only  
60-65 degrees at night & I love having the attic fan on, love having the breeze  
through the house. Is it more economical to have the attic fan running all night  
as opposed to having the AC set at 75?

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**Author:** ![Joey\_P](https://avatars.discourse-cdn.com/v4/letter/j/919ad9/32.png) [@Joey\_P](https://boards.straightdope.com/u/Joey_P)\
**Post date:** [September 8, 2004, 11:13am UTC](https://boards.straightdope.com/t/attic-fan-on-all-night-or-ac-on-off-all-night-which-is-cheaper/263622/2 "2004-09-08T11:13:00Z")

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An attic fan should be much cheaper to run then an AC. Generally compressors suck up alot of energy (ie AC, fridge…)

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**Author:** ![dfqforever](https://avatars.discourse-cdn.com/v4/letter/d/439d5e/32.png) [@dfqforever](https://boards.straightdope.com/u/dfqforever)\
**Post date:** [September 8, 2004, 2:19pm UTC](https://boards.straightdope.com/t/attic-fan-on-all-night-or-ac-on-off-all-night-which-is-cheaper/263622/3 "2004-09-08T14:19:48Z")

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Thanks, JoeyP, I appreciate the info. Anytime I can make my utility bill smaller,  
I’m happy!

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**Author:** ![Sharky](https://avatars.discourse-cdn.com/v4/letter/s/bbce88/32.png) [@Sharky](https://boards.straightdope.com/u/Sharky)\
**Post date:** [September 9, 2004, 6:09am UTC](https://boards.straightdope.com/t/attic-fan-on-all-night-or-ac-on-off-all-night-which-is-cheaper/263622/4 "2004-09-09T06:09:25Z")

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Installing a timer switch for the fan helps, too. Home Depot carries timer switches that replace the fan’s wall switch, a cheap and easy 15 minute project.