Renewable Heating Hub Heat Pump Forums

Search with Wattson
Forums
Renewable Heating
Air Source Heat Pum...
How to Zone with a ...
 
Notifications
Clear all

Joining the Renewable Heating Hub forums is completely free and only takes a minute. By registering you’ll be able to ask questions, join discussions, follow topics you’re interested in, bookmark useful threads and receive notifications when someone replies. Non-registered members also do not have access to our AI features. When choosing your username, please note that it cannot be changed later, so we recommend avoiding brand or product names. Before registering, please take a moment to read the Forum Rules & Terms of Use so we can keep the community helpful, respectful and informative for everyone. Thanks for joining!

How to Zone with a Single Room with UFH

 
Air Source Heat Pumps (ASHPs)
Last Post by Judith 11 months ago
2 Posts
2 Users
2 Reactions
1,112 Views
RSS
 Renewables345
(@renewables345)
Eminent Member Member
Joined: 11 months ago
Posts: 12
Topic starter 19/09/2025 2:27 pm   [#2469]

Hi all,

 

I am currently looking at a project to fit an ASHP for a client. I haven't come across this before, but I wouldn't imagine it being too uncommon nowadays. The ground floor is all radiators except for one room, which is an extension with underfloor heating. The first floor is then radiators. What are the options here? 

 

I tried speaking to Vaillant, but I didn't seem to get anywhere, what's your guys recommendations.

 

Thanks,



   
Quote
Topic Tags
ASHP Zoning UFH
 Judith
(@judith)
Prominent Member Member
Joined: 3 years ago
Posts: 549
21/09/2025 1:45 pm  

We have exactly what you describe, one utility room with UFH but radiators elsewhere.

Design one single open loop, increase radiator size if need on a room by room basis. Use a down-mixer for UFH section from overall design flow temperature (often 45C or 50C) for worst external temp (often -2C). 

The installer was trained through the Heatgeek system, changed the main pipe flow from ashp to DHW cylinder from 22mm to 26mm diameter and also about 15m of first section of main feed to radiators. The only “thermostat” box is the Vaillant control box in the entrance hall. Weather compensation set up with the slope parameter at 0.6.

The key to getting the design right is the heat loss analysis of the house. Personally I like the Heatpunk software.


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


   
👍
🙏
2
ReplyQuote
Forum Jump:
  Previous Topic
Next Topic  
Related Topics
Topic Tags:  ASHP (88) , Zoning (2) , UFH (13) ,
Share:

SPONSORS

Join Us!

Installer Finder

Degrees of Separation

Latest Posts

SPONSORS

Members Online

Click to access the login or register cheese
Protected By
Shield Security PRO