Forums

Forums
Renewable Heating
Air Source Heat Pum...
What is the maximum...
 
Notifications
Clear all

What is the maximum output of the Vaillant 7kW Arotherm Plus

 
Air Source Heat Pumps (ASHPs)
Last Post by Judith 1 week ago
6 Posts
5 Users
2 Reactions
106 Views
RSS
 AdamK
(@adamk)
Estimable Member Member
179 kWhs
Joined: 2 weeks ago
Posts: 29
Topic starter 01/03/2025 9:11 pm  

what is the max this HP can output? are they under the rating or over?

heat loss on my property is 5.58kw-6.8kw depending on surveyor.

This topic was modified 1 week ago by Mars

   
Quote
Mars
 Mars
(@editor)
Illustrious Member Admin
26249 kWhs
Veteran
Joined: 4 years ago
Posts: 2978
01/03/2025 10:56 pm  

Data badges are performance labels for heat pumps that show how much heat they can produce at different outdoor temperatures. For example, a heat pump might output 8 kW at 7C but only 5 kW at -3C. These numbers are crucial because they tell you how well your heat pump will perform in different weather conditions.

Since you have a Vaillant 7 kW Arotherm Plus. At 7C, it should output around 7 kW, which is its rated capacity. At -3°C, the output drops to about 5.5–6 kW, depending on settings.

Your heat loss is 5.58–6.8 kW, so the Arotherm Plus should be able to handle most of your heating needs. However, during extreme cold (e.g., below -3C), it might struggle to meet the upper end of your heat loss (6.8 kW), and you might need to rely on backup heating during those cold snaps.

Buy Bodge Buster – Homeowner Air Source Heat Pump Installation Guide: https://amzn.to/3NVndlU
From Zero to Heat Pump Hero: https://amzn.to/4bWkPFb

Subscribe and follow our Homeowners’ Q&A heat pump podcast


   
👍
1
ReplyQuote
 JohnR
(@johnr)
Estimable Member Member
726 kWhs
Joined: 3 months ago
Posts: 95
02/03/2025 8:33 am  

According the the Vaillant app, my 7kW Arotherm+ produced 7.6kW when the outside temperature was -7C.


   
🤩
1
ReplyQuote



 JamesPa
(@jamespa)
Famed Member Moderator
10711 kWhs
Veteran
Joined: 2 years ago
Posts: 2018
02/03/2025 8:58 am  

Posted by: @adamk
↑

what is the max this HP can output? are they under the rating or over?

heat loss on my property is 5.58kw-6.8kw depending on surveyor.

There is a table here showing figures generally well above 7kW 

PROFESSIONAL.VAILLANT.CO.UK "https://professional.vaillant.co.uk/downloads/aproducts/renewables-1/arotherm-plus/arotherm-plus-installer-quick-guide-2848532.pdf"

However there has been recent speculation that these figures are gross output and do not take into account defrost cycles (which, if it is the case, is rather misleading).

https://community.openenergymonitor.org/t/vaillant-maximum-output-capacity-testing/27221

https://community.openenergymonitor.org/t/vaillant-maximum-output-capacity-testing/27221/62?page=4

It might be wise to ask the question explicitly of Vaillant Tech support if you are marginal. They are generally very helpful at least in my experience.

My heat loss is 7kW (or 16kW if you believe two surveyors!); the 7kW Vaillanthas worked for me in practice, Ive only had it since November though, design OAT-2.

 

This post was modified 1 week ago 2 times by JamesPa

4kW peak of solar PV since 2011; EV and a 1930s house which has been partially renovated to improve its efficiency. 7kW Vaillant heat pump.


   
ReplyQuote
 AdamK
(@adamk)
Estimable Member Member
179 kWhs
Joined: 2 weeks ago
Posts: 29
Topic starter 02/03/2025 2:18 pm  

Thanks all. Think it should be ok. If not I’ll start upgrading rads in cold rooms.


   
ReplyQuote
 Judith
(@judith)
Honorable Member Member
2549 kWhs
Joined: 1 year ago
Posts: 298
02/03/2025 3:26 pm  

On the Vaillant app our 7kW showed9.1kW at ~+2C. I suspect that is a bit on the high side of the measurement accuracy though.

@adamk your surveyor may suggest radiator changes for some rooms, but but you can decline.

2kW + Growatt & 4kW +Sunnyboy PV on south-facing roof Solar thermal. 9.5kWh Givenergy battery with AC3. MVHR. Vaillant 7kW ASHP (very pleased with it) open system operating on WC


   
ReplyQuote
Forum Jump:
  Previous Topic
Next Topic  



Share:

Join Us!

Heat Pump Dramas?

Thinking about installing a heat pump but unsure where to start? Already have one but it’s not performing as expected? Or are you locked in a frustrating dispute with an installer or manufacturer? We’re here to help.

✅ Pre-Installation Planning
✅ Post-Installation Troubleshooting
✅ Performance Optimisation
✅ Complaint Support (Manufacturer & Installer)

👉 Book a one-to-one consultation now.

Latest Posts

x Powerful Protection for WordPress, from Shield Security
This Site Is Protected By
Shield Security →