UFH design - help / recommendations?

[Great_scot_selfbuild]

Happy New Year all,

 

I thought I had a good solution for my UFH, but having re-read the quote (111 sqm, 2 zones) it only specifies 2 circuits. I was happy with the quote (£1083) but I’ve not yet paid the £120 for the UFH design as I have heard of others offering this as ‘free’ (though they will undoubtedly wrap the cost up in other ways - such as another quote I had for £1600 with a free design included).

 

Another reason was that when I asked how they only calculated 2 circuits, it turns out this estimate was based on their simple tool that uses the total sqm and when I questioned about pressure loss over a long circuit, they clearly didn’t know (could have just been the sales person lacking knowledge).

 

I had intended to use LoopCAD to do my own checking but I now find that it only works on Windows OS (yet another reason for me to be frustrated at committing to Apple…).

 

So… I’m looking for some help to check what i should be expecting from a UFH design, advice on different circuit designs (spiral / serpentine etc.), and any recommendations for a design or design & supply service (I’ll be installing myself).

 

Thanks 😁

 

 

 

 

 

[JohnMo]

My stock answer is single zone, no mixers or additional pumps other that provided by heat source.

 

Keeps it simple and costs low. All you need is pipes and manifold, no actuators or zone valves. If heat pump run everything from heat pump controller.

 

Best design is to match floor output to room demand for each room. Then balancing is easy. No need for additional loops in halls, just space the loops transiting through halls out as if it was a loop.

 

That hall is massive, would be stealing some space from it, for other rooms.

[Great_scot_selfbuild]

Thanks @JohnMo I am inclined to go for single zone, but we were just hesitant about whether the living room would heat up too much (no opening window - relying on MVHR).

 

Yes, it’s a big hall, but that ship has sailed into the distance now, and it does feel like a good space.

[JohnMo]

20 minutes ago, Great_scot_selfbuild said:

no opening window

Bad idea for summer.

 

But balance output, no issue, UFH in a low energy house is pretty good at self regulation, as floor temp isn't much warmer than room temp. So room heats up, floor stops output.

[Spinny]

Circuits/loops and Zones are two different things - presumably you are aware of that.

 

Do you have a design that actually provides the pipe layouts ? Our suspended floor system design included the proposed pipe layouts.

Are you going to put pipes under the island and banquette seating ? Views seem to differ, architects argue the u/f heating is for life of building so should allow future internal reconfiguration.

 

(I have no expertise here, but is it not a good idea to ensure you have sufficient loops to provide some resilience should the worst ever happen - i.e. a loop fail, get punctured etc.)

 

Do think about ventilation and solar gain. Having had a cold house we thought it would take care of itself and our architect never once mentioned it as something requiring design. Depending which way your glass faces and what it is, solar gain can be significant.

 

Only one appliance in the utility ? Or is that X a washer and dryer stacked on top of each other ?

[Great_scot_selfbuild]

5 hours ago, Spinny said:

Circuits/loops and Zones are two different things - presumably you are aware of that.

 

Do you have a design that actually provides the pipe layouts ? Our suspended floor system design included the proposed pipe layouts.

Are you going to put pipes under the island and banquette seating ? Views seem to differ, architects argue the u/f heating is for life of building so should allow future internal reconfiguration.

 

(I have no expertise here, but is it not a good idea to ensure you have sufficient loops to provide some resilience should the worst ever happen - i.e. a loop fail, get punctured etc.)

 

Do think about ventilation and solar gain. Having had a cold house we thought it would take care of itself and our architect never once mentioned it as something requiring design. Depending which way your glass faces and what it is, solar gain can be significant.

 

Only one appliance in the utility ? Or is that X a washer and dryer stacked on top of each other ?

circuit vs zones.yes, aware of the difference which prompted this thread - I was surprised the company had only recommended one circuit for a rather large zone.

 

We don’t have a design yet - that company just gives an initial quote but then you have to pay for a design (I’ve found someone else who I’m waiting on a design from now).

 

Pipes are only in the coloured areas - i.e. not under permanent fittings such as bench seating and island.

 

I was expecting multiple loops simply because of the pressure losses (building being 18m long means a single circuit would be huge!)

 

We’ve had a full part O modelling done, so all good for the solar aspects.

 

You’re correct - the X is a washer & drier stacked.

[Nickfromwales]

11 hours ago, Great_scot_selfbuild said:

I was surprised the company had only recommended one circuit for a rather large zone.

Did they demonstrate how long the 2 loops would each be?

 

For this amount of m2 I would be looking elsewhere as the loop lengths would be crazy long, and the effectiveness of the loop pretty dire; energy disrupted into the slab would soon sap the heat out of the pipe long before it had returned to the manifold.

 

Thos installer needs to be binned off afaic.

[Great_scot_selfbuild]

3 hours ago, Nickfromwales said:

Did they demonstrate how long the 2 loops would each be?

 

For this amount of m2 I would be looking elsewhere as the loop lengths would be crazy long, and the effectiveness of the loop pretty dire; energy disrupted into the slab would soon sap the heat out of the pipe long before it had returned to the manifold.

 

Thos installer needs to be binned off afaic.

I have ‘binned them’ for exactly that reason, confirmed by the fact they couldn’t explain how they had calculated it. 
 

just about to post a new thread with some different but similar queries.