# Heat pump oversizing data analysis

**URL:** <https://community.openenergymonitor.org/t/heat-pump-oversizing-data-analysis/25971>\
**Category:** Labs\
**Created:** [12 April 2024 12:11 UTC](https://community.openenergymonitor.org/t/heat-pump-oversizing-data-analysis/25971 "2024-04-12T12:11:18Z")\
**Posts on this page:** 2\
**Page:** 2

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**Author:** ![TrystanLea](https://community.openenergymonitor.org/user_avatar/community.openenergymonitor.org/trystanlea/32/31_2.png) [@TrystanLea](https://community.openenergymonitor.org/u/TrystanLea)\
**Post date:** [29 January 2025 08:44 UTC](https://community.openenergymonitor.org/t/heat-pump-oversizing-data-analysis/25971/21 "2025-01-29T08:44:39Z")

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> [@ectoplasmosis](#):
>
> I believe it’s important, in the case of Vaillant units, to factor in the relationship between nominal capacity (5kW, 7kW, 10kW etc) which essentially correlate to mean outputs at worst-case conditions, and quoted spec sheet outputs which are peak output not achievable over time during defrost conditions.

Taken into account for Vaillants in the above figures. These are calculated as:

```
margin factor = max output test result (defrost tests) / measured max heat demand

```

If they are not Vaillants and we dont have data on the max outputs then it defaults to the datasheet max output.

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<div class="post-metadata">

**Author:** ![TrystanLea](https://community.openenergymonitor.org/user_avatar/community.openenergymonitor.org/trystanlea/32/31_2.png) [@TrystanLea](https://community.openenergymonitor.org/u/TrystanLea)\
**Post date:** [29 January 2025 08:47 UTC](https://community.openenergymonitor.org/t/heat-pump-oversizing-data-analysis/25971/22 "2025-01-29T08:47:01Z")

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Here’s the result for Vaillant only:

 ![image](https://community.openenergymonitor.org/uploads/default/original/3X/1/7/1754fdb1c0f5572a9537feedc9e43acbb810c732.png)

We probably need a different term for margin factor based on defrost test output and margin factor based on badge or max datasheet output as it could be quite easy to get confused about which one we are talking about…

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