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!
Advice on ball park radiator sizes please
Posted by: @derek-mI'm afraid that I do not follow your logic, since heat loss is heat loss and is not dictated by the radiator size or type. Different size or type of radiators will merely require a higher or lower water temperature so that the thermal energy output matches the present heat loss.
Sorry, I obviously didn’t explain that very well, and wrong to boot. As you say, the room/house heat loss is fixed and determined by the fabric and outside temperature, etc. the radiators would then be chosen to provide that output at the desired flow temperature and flow rate, again as you state. I was speculating that the values might be for the standard 50C but without checking the actual radiator specifications and so misled myself on the figures, the Stelrad k3 700x2000 for instance looks like it outputs 5424W at delta-t 50 according to the data sheet, which is considerably higher than the values given. Please ignore my mistaken intrusion.
Thank you all - so grateful for your advice.
I went back to the company, and they forwarded my query to another branch (the original person being away for 3 weeks). The person there confirmed there was an error - apparently the original guy had read the wrong column of figures or something...
So I now have a revised set of sizes, which are much closer to what I anticipated:
|
Room |
Watts required |
Suggested radiator |
Radiator type |
|
|
|
|
|
|
|
|
Living room |
|
|
|
UFH |
|
Shower room |
|
|
|
|
|
Kitchen |
|
|
|
|
|
Dining hall |
|
|
|
|
|
Hall |
|
|
|
|
|
Landing (1st floor) |
700 |
600x600 |
K2 |
|
|
Study |
1050 |
600x600 |
K2 |
|
|
Sitting room |
1600 |
600x1000 |
K2 |
|
|
Bed 1 |
1500 |
600x1000 |
K2 |
|
|
Bed 2 |
1600 |
600x1000 |
K2 |
|
|
Bed 3 |
1550 |
600x1000 |
K2 |
|
|
Landing (2nd floor |
700 |
600x600 |
K2 |
Somewhat different to the originals!
I would suggest that you ask the company to provide a full set of heat loss calculations for your home. Also ask them to clarify what is meant by 'Watts required' in the table, and to confirm their calculated Leaving Water Temperature (LWT) coming from the heat pump.
- 26 Forums
- 2,715 Topics
- 63.6 K Posts
- 223 Online
- 7,116 Members
Join Us!
Installer Finder
Degrees of Separation
Latest Posts
-
RE: Comms and power cabling to outside unit
@jamespa Thanks James. I’ll see what they say. I alw...
By Papahuhu , 9 hours ago
-
RE: Vaillant Arotherm Pro vs new Plus
when our system was installed in September 2 years ago ...
By Judith , 9 hours ago
-
RE: Rate the quality of your heat pump design and installation
I had a Heat Geek lead install by Green Heat Norfolk. T...
By Orlando , 18 hours ago
-
+1 that works well If most of the thermal mass is in ...
By bobflux , 1 day ago
-
RE: Mitsubishi Ecodan FTC6 settings
While @F1p's dongles are great, the FTC can do this its...
By RobS , 1 day ago
-
RE: Samsung heat pump - data cable issue
If it's a data cable, current will be minuscule, voltag...
By bobflux , 1 day ago
-
RE: MCS Quality Audit – Has Anyone Had One? Did It Lead to Remediation?
I got hit with an RHI audit in 2022. It was far from c...
By Abernyte , 2 days ago
-
RE: Electricity price predictions
@papahuhu Groucho Marx had something to say about no...
By Toodles , 2 days ago
-
RE: Octopus Cosy Heat Pump Owners & Discussion Thread
@jamespa haha very true, although the engineer yesterda...
By swwils , 2 days ago
-
RE: What a difference a few degrees make.
Wow. Having accepted the challenge, I ran the cold tap ...
By Old_Scientist , 3 days ago
-
RE: HeatPump maintenance in Swindon area?
@vince31 have you tried using our finder:/p>
By Mars , 3 days ago
-
Looking for beta testers for a new homeowner heat pump tool
Over the past few months I've been building a brand new...
By Mars , 3 days ago
-
-
RE: Indevolt Batteries UK Support & Info Thread
It depends on how you configure it via the app. The ma...
By JamesPa , 3 days ago



