help sizing rads based on room by room heat loss
Posted by: @jamespaPosted by: @adamk@jamespa thanks for the info but I think I must have something wrong. The heat loss for the whole house is about 7.5kw. The room is only 3.756m x 3.686m. Current rad is a P+ 1450mm 380mm.
Have you got the loss calculations, if so perhaps you could post?
My house loss is also about 7kW and I had one room well over 1kW, went for a Mitsubishi fancoil for that, very nice piece of kit
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.
@jamespa heat loss list on first post.
it’s the one that says nearly 2kw, I’ve just split it into 2 rooms as we’re going to put a sliding wall between the dining and living room, plus one rad is in one area and another in the other.
Posted by: @adamk@jamespa heat loss list on first post.
it’s the one that says nearly 2kw, I’ve just split it into 2 rooms as we’re going to put a sliding wall between the dining and living room, plus one rad is in one area and another in the other.
The living/lounge and kitchen in your list aren't dissimilar to mine and were, for me, by far the most difficult rooms to find radiators for. I ended up with four rads in total covering a kitchen/living room and a separate long living room. The balance between two halves of each room wasn't perfect, but it hasn't mattered in practice. One of the four rads was a mitsubishi fancoil and another was the existing rad with a bunch of computer fans added (not sure how much difference that has actually made)..
I avoided type 33 as I had already fitted one in the bedroom (the other difficult room) and the wife hates it. Personally I quite like it as it looks 'serious - but I would advise to look at an example of a type 33 before settling on one, they are quite noticeably deeper.
Having got a fancoil I wish we had got a couple more. They are nice and neat, quite small, not particularly noisy and with three of them I might have been able to do some meaningful cooling in summer. Jaga Strada are also popular fan radiators and those who have them seem to rate them highly..
I was designing for 45C where the oversize factor (ie the factor by which you have to divide the DT50 output to get the output at the chosen FT) is 2.8. At 40C its 3.9 which makes quite a difference. In practice Im running at 42 so half way in between, presumably because the loss was a bit overestimated.
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.
Posted by: @adamk@jamespa so if i have a 1988w rad at 40c @-3.1 it will only be 509w?
If its 1988W at DT 50, which is how most radiators are specified (but note not all, one brand is specified at DT70!) then yes that's right. At FT40 and RT 20 your average DT is 17.5. So your rad output is 1988*(17.5/50)^1.3 = 509W.
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.
- 26 Forums
- 2,153 Topics
- 47.3 K Posts
- 49 Online
- 5,673 Members
Join Us!
Podcast Picks
Latest Posts
-
RE: Failing heat pump system - seeking thoughts on a rebuild
@bontwoody I think flow / return are 1 inch. I should p...
By Cleardene-ashp , 55 minutes ago
-
RE: Electricity price predictions
@tim441 Puts even more reason behind any proposal to ha...
By Toodles , 6 hours ago
-
RE: Can you help with our research: solar panels, EV chargers, home batteries, heat pumps?
I have signed up as well. @belsnugg could you outline ...
By JamesPa , 7 hours ago
-
RE: New Vaillant aroTherm Plus in black - When will it come to the UK?
Ooh, heat pumps in neon blue wrap 🤣 🤣 &...
By Old_Scientist , 8 hours ago
-
@profzarkov Good to know in case it ever happens to me...
By bontwoody , 1 day ago
-
RE: Are Octopuses Slowing Consumer Adoption of Heat Pumps?
I mean, is this surprising? The local installers in my ...
By Alex , 1 day ago
-
@old_scientist sorry, I should have made it clear that ...
By GrahamF , 1 day ago
-
RE: Mitsubishi Ecodan 11kw Defrosting Issue.
@thundermink can you provide photos to illustrate your ...
By Morgan , 1 day ago
-
RE: Boiling Mad: Exposing Radiatorgate
Hi @Rob, I’d be more than happy to contribute. I have ...
By DREI , 1 day ago
-
RE: Solar Power Output – Let’s Compare Generation Figures
@andris a great year - very happy with our system
By Profzarkov , 1 day ago
-
RE: A Customer's Lessons Learnt from a Heat Pump Installation in a Large House
After our rather lengthy meander off piste, I thought I...
By GrahamF , 1 day ago
-
RE: Midea ASHP – how to set weather compensation
@pash44pump - to collect the IAT/OAT data, can I sugges...
By cathodeRay , 1 day ago
-
RE: Ecodan software update. Real or scam?
@vinz86 Contact Mitsubishi and an engineer attends and ...
By ASHP-BOBBA , 2 days ago
-
@drei When I was in local government we were of cours...
By JamesPa , 2 days ago
-
RE: Heat Pump SCOPs – The Truth Might Not Be What You Think
Sufficient system volume is also essential for ensuring...
By Old_Scientist , 2 days ago
-
RE: Flexi-Orb Heat Pump Scheme: A Game-Changer for the UK's Heat Pump Industry
As someone who has suffered from a Heat Pump installati...
By DREI , 3 days ago
-
RE: What crazy nonsense are inverter limits and why are they imposed?
I’ve also got a dual fuel Rangemaster. We originally ha...
By Majordennisbloodnok , 3 days ago
-
RE: Octopus tariffs - a quick comparison
@tim441 I’d agree wholeheartedly with that, with 2 x Po...
By Toodles , 3 days ago