# Estimating my electric bill if I add A/C **URL:** \ **Category:** Factual Questions\ **Created:** [March 20, 2019, 2:17am UTC](https://boards.straightdope.com/t/estimating-my-electric-bill-if-i-add-a-c/831402 "2019-03-20T02:17:06Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![Newtosite](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/newtosite/32/8623_2.png) [@Newtosite](https://boards.straightdope.com/u/Newtosite)\ **Post date:** [March 20, 2019, 2:17am UTC](https://boards.straightdope.com/t/estimating-my-electric-bill-if-i-add-a-c/831402/1 "2019-03-20T02:17:06Z")
I’m thinking of installing central A/C for the first time. Is there a way to estimate how much higher my monthly electric bill will be if I run a 3.5 ton A/C for six hours a day? I hope to only use it when the inside temp is 84 F or above. According to my bill, I’m paying $0.16723/kWh plus a 10% surcharge fee. Thank you! ---
**Author:** ![am77494](https://avatars.discourse-cdn.com/v4/letter/a/d2c977/32.png) [@am77494](https://boards.straightdope.com/u/am77494)\ **Post date:** [March 20, 2019, 2:35am UTC](https://boards.straightdope.com/t/estimating-my-electric-bill-if-i-add-a-c/831402/2 "2019-03-20T02:35:03Z")
That works out to about 6300 W or 6.3kW. So assuming a 30 day month : 30 x 6 x 6.3 x 0.16723 x 1.1 = $208.6 This is assuming that the AC runs continuously for 6 hours, in fact it may not do so. ---
**Author:** ![Newtosite](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/newtosite/32/8623_2.png) [@Newtosite](https://boards.straightdope.com/u/Newtosite)\ **Post date:** [March 20, 2019, 3:29am UTC](https://boards.straightdope.com/t/estimating-my-electric-bill-if-i-add-a-c/831402/3 "2019-03-20T03:29:16Z")
Thanks, am77494. Does it use electricity to go on and off, or am I only charged for the time it’s actually running?