First floor, no radiators/larger radiators ???

[Post and beam]

 

This relates to well insulated new builds i guess, and not the retrofit strategy of larger radiators into older houses where it might be the way to go.

 

I dont believe that those of you with ASHP's & UFH on the ground floor are running their upper floor radiators( if you even have any) at the same temperature as the hopefully low flow temperature that we would all wish for. Sub 35 degrees in my case.

 

So assuming a well insulated/airtight house what flow temperature is considered best practice upstairs?

 

The reason for asking is because i still cannot get my proposed ASHP installation supplier to think anything other than running the same flow temperature on both floors.

[JohnMo]

  On 10/03/2025 at 16:01, Post and beam said:

what flow temperature is considered best practice upstairs?

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I would be aiming at same as ground floor, no additional mixers or additional pump required for UFH. Then all you need in the house is a diverter valve between DHW cylinder and heating system. Add TRVs to rads only if you really need them.

 

Or fit fan coils to bedrooms.

Edited March 10 by JohnMo

[Post and beam]

Hi JohnMo

 

Thanks, what that means then is that people building their lovelly dream homes are lumbered with overly large radiatiors when i would imagine most people would want to go exactly the opposite way. I certianly regard larger radiators as a disaster. Thats if you are chasing the grant anyway, which i am.

 For the above reason my supplier is saying 45 degree flow in the UFH . I have opened a thread about this previously as 45 degrees does not seem like it would be efficient or desirable. If i had not already paid them a large deposit i think i would be looking at another option.

[JohnMo]

  On 10/03/2025 at 16:25, Post and beam said:

For the above reason my supplier is saying 45 degree flow in the UFH

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So he is just playing with numbers, to fudge the design, for your benefit. The likelihood of a new build actually running at 45 degrees to UFH is none existent. So you are getting small radiators you want. You will just operate the same temperature as the UFH - so low temperature.

 

So long as he does the design without buffer and mixers, the reality is you will run low 30 or less on the coldest day. Do you actually need bedrooms with rads in a new build airtight well insulated build? Unlikely, but they will add capacity to system when on which is good.

Edited March 10 by JohnMo

[nod]

Even the mass produced home builders are only sticking tiny Rads in the bedrooms 

After never using our first floor Rads on our previous build My wife didn’t want any radiators 

But I still installed them with one eye on one day selling the house 

 

[SBMS]

How about UFH upstairs?

[DownSouth]

  On 10/03/2025 at 16:25, Post and beam said:

If i had not already paid them a large deposit i think i would be looking at another option.

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We managed to get a refund for our design (£500 paid) because after a lot of back and forth they agreed they couldn’t design the system we wanted (one zone upstairs, one zone down) and wanted to do a zone per room. Worth discussing a refund if you need a low flow system and they can’t design what you want. Don’t let them give you nonsense solutions which you’ll not be using once you live in the house.

[MrPotts]

  On 10/03/2025 at 18:47, DownSouth said:

We managed to get a refund for our design (£500 paid) because after a lot of back and forth they agreed they couldn’t design the system we wanted (one zone upstairs, one zone down) and wanted to do a zone per room. Worth discussing a refund if you need a low flow system and they can’t design what you want. Don’t let them give you nonsense solutions which you’ll not be using once you live in the house.

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Do you want one zone upstairs and one zone downstairs or do you want a zone per room? Its better to have no zones with a heat pump.

[Post and beam]

  On 10/03/2025 at 19:13, MrPotts said:

Do you want one zone upstairs and one zone downstairs or do you want a zone per room? Its better to have no zones with a heat pump.

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I only want one zone, but was told build regs require at least two, 'in a house of that size'. Its only 200 sq metres. So two zones both set to the same temperature most likely.

[JohnMo]

  On 11/03/2025 at 09:29, Post and beam said:

I only want one zone, but was told build regs require at least two, 'in a house of that size'. Its only 200 sq metres. So two zones both set to the same temperature most likely.

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Part L of building regs actually states the following  for heat pumps

 

6.39 The heat pump should have external controls that include both of the following.

a. Weather compensation or internal temperature control.

b. Timer or programmer for space heating.

 

So you don't really need any temperature controls. Heat pumps should always be set to run WC, it is normal for the manufacturers controller to have a timer or programmer built-in.

 

Part L is full of contradiction, so use which you feel suit you.

 

But if push comes to shove, a trv with a timer is a zone.

[Dave Jones]

  On 10/03/2025 at 16:01, Post and beam said:

 

This relates to well insulated new builds i guess, and not the retrofit strategy of larger radiators into older houses where it might be the way to go.

 

I dont believe that those of you with ASHP's & UFH on the ground floor are running their upper floor radiators( if you even have any) at the same temperature as the hopefully low flow temperature that we would all wish for. Sub 35 degrees in my case.

 

So assuming a well insulated/airtight house what flow temperature is considered best practice upstairs?

 

The reason for asking is because i still cannot get my proposed ASHP installation supplier to think anything other than running the same flow temperature on both floors.

Expand  

 

without question fancoil units in bedrooms. primarily for cooling. wouldnt be without them having experienced last summer.