# Difference between two temperatures

**URL:** <https://community.homey.app/t/difference-between-two-temperatures/78217>\
**Category:** Questions & Help\
**Created:** [March 22, 2023, 10:54am UTC](https://community.homey.app/t/difference-between-two-temperatures/78217 "2023-03-22T10:54:55Z")\
**Posts on this page:** 8\
**Page:** 1

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**Author:** ![Matthieu\_Moreau](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/matthieu_moreau/32/57526_2.png) [@Matthieu\_Moreau](https://community.homey.app/u/Matthieu_Moreau)\
**Post date:** [March 22, 2023, 10:54am UTC](https://community.homey.app/t/difference-between-two-temperatures/78217/1 "2023-03-22T10:54:55Z")

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Good morning,

I would like to calculate the difference between two temperatures (exterior and a sensor) but I can’t.

Could you help me ?

I tried this:

![image](https://us1.discourse-cdn.com/flex025/uploads/athom/original/3X/f/d/fd71d7bfca3894692b81ae8e65addd70ca7bb37f.png)

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**Author:** ![Caseda](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/caseda/32/138695_2.png) [@Caseda](https://community.homey.app/u/Caseda)\
**Post date:** [March 22, 2023, 11:40am UTC](https://community.homey.app/t/difference-between-two-temperatures/78217/2 "2023-03-22T11:40:04Z")

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What are you trying to do with the difference, put it into a logic variable (then you are using the wrong calculation flowcard, you need the “logic” calculate flow card), or use it in the flow utilities app, but then don’t think that that calculation card is what you think it means, as it is very specific for the use case of that app.

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**Author:** ![Matthieu\_Moreau](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/matthieu_moreau/32/57526_2.png) [@Matthieu\_Moreau](https://community.homey.app/u/Matthieu_Moreau)\
**Post date:** [March 22, 2023, 12:02pm UTC](https://community.homey.app/t/difference-between-two-temperatures/78217/3 "2023-03-22T12:02:58Z")

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Good morning

thank you for your answer, I need to know when my greenhouse has 5° more than the outside temperature.

Obviously I have a different sensor.

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**Author:** ![Peter\_Kawa](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/peter_kawa/32/173848_2.png) [@Peter\_Kawa](https://community.homey.app/u/Peter_Kawa)\
**Post date:** [March 22, 2023, 4:13pm UTC](https://community.homey.app/t/difference-between-two-temperatures/78217/4 "2023-03-22T16:13:07Z")

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I give you an example of what @caseda tried to explain  
You’ll need to create a numeric variable up front,  
then you can do the calculation, with this Homey Logics card:

 ![Screenshot from 2023-03-22 17-17-10](https://us1.discourse-cdn.com/flex025/uploads/athom/original/3X/5/8/5826657af44953e3c147cdb1efb0743bf2ccff0e.png)

like this:

 ![Screenshot from 2023-03-22 17-10-37](https://us1.discourse-cdn.com/flex025/uploads/athom/original/3X/7/d/7dde4d4bd550b766f9fdb3b9958b1680fb99c747.png)

The brackets {{}} are important in the calculation:

```auto
{{[Temperature1]-[Temperature2]}}

```

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**Author:** ![JvdMeulen](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/jvdmeulen/32/71049_2.png) [@JvdMeulen](https://community.homey.app/u/JvdMeulen)\
**Post date:** [March 22, 2023, 7:41pm UTC](https://community.homey.app/t/difference-between-two-temperatures/78217/5 "2023-03-22T19:41:26Z")

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You can also check it with this logic

 ![Capture 2023-03-22 at 20.40.06@2x](https://us1.discourse-cdn.com/flex025/uploads/athom/original/3X/d/f/dfb4876f14dd4691e5efbd2b274fb1c03959c9b0.png)

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**Author:** ![Matthieu\_Moreau](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/matthieu_moreau/32/57526_2.png) [@Matthieu\_Moreau](https://community.homey.app/u/Matthieu_Moreau)\
**Post date:** [March 22, 2023, 7:53pm UTC](https://community.homey.app/t/difference-between-two-temperatures/78217/6 "2023-03-22T19:53:04Z")

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Great, it works nikel, thank you very much

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<div class="post-metadata">

**Author:** ![Matthieu\_Moreau](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/matthieu_moreau/32/57526_2.png) [@Matthieu\_Moreau](https://community.homey.app/u/Matthieu_Moreau)\
**Post date:** [March 22, 2023, 8:02pm UTC](https://community.homey.app/t/difference-between-two-temperatures/78217/7 "2023-03-22T20:02:32Z")

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Good morning @JvdMeulen

could you show me the location in logic, i can’t find this card

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**Author:** ![Arie\_J\_Godschalk](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/arie_j_godschalk/32/63027_2.png) [@Arie\_J\_Godschalk](https://community.homey.app/u/Arie_J_Godschalk)\
**Post date:** [March 22, 2023, 8:09pm UTC](https://community.homey.app/t/difference-between-two-temperatures/78217/8 "2023-03-22T20:09:20Z")

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Thats the Number is greater than or equel to [number] is true card.

It’s an And card, instead of a Then card.