UFH Design and Zoning - Self Build

[iMCaan]

Hi

 

I'm looking for some advice regarding UFH design and zoning on both GF and FF. 

 

I have received the attached pipe layout plans for GF and FF from Wunda. I know a lot of people here don't prefer zoning but I think zoning will work for me.

 

On the GF, we have an L shape open plan room and I have split that into three zones.
The utility room is a secondary kitchen (demanded by my other half). Should it be zoned?

 

In regards to FF, I think I've definitely over done the zoning. I prefer each bedroom to be zoned.

 

Should the the hallways and bathrooms be zoned.

 

How can this initial UFH design be improved?

Any suggestions/comments are highly appreciated.
 

Thanks

[Lofty718]

UFH should not be zoned at all and kept as open loop as possible. One zone upstairs one zone downstairs

[Adsibob]

15 minutes ago, Lofty718 said:

UFH should not be zoned at all and kept as open loop as possible. One zone upstairs one zone downstairs

Horses for courses. Sometimes zoning can be very useful, particularly in a house as big as the OP’s where usage patterns for different rooms might be very different.

[JohnMo]

8 minutes ago, Lofty718 said:

UFH should not be zoned at all and kept as open loop as possible. One zone upstairs one zone downstairs

Exactly what I would say also.

 

But do you really need UFH upstairs? Wet rooms yes, bedrooms? UFH is very slow by nature to heat up and cool down, when most likely you need a blast of heat first thing and just prior to bedtime. Once in bed you want it cool down for sleeping. UFH will keep pumping out the heat for hours.  Most well insulated houses with an upstairs will just take the heat, that is rising from downstairs. 

 

I would, UFH downstairs and upstairs wet rooms only, electric panel heater with timer and thermostat, just in case you need it, in bedrooms. Also electric towel rads in bathrooms.

 

UFH - Run the whole lot on a single zone, no actuators, thermostat to give boiler or really assume ASHP the start/stop permissive, run the whole lot from the ASHP circulation pump.

 

Comments on ground floor plan

Hall and cloakroom delete those loops. Your hall already has loads of pipes going through it, spread them across the floor and borrow their heat. Cloak and utility do as a single loop, flow through cloak then to utility.

[ProDave]

For a start you DO NOT NEED UFH ON A LANDING.  I shouted that because any UFH designer that says you do, knows nothing about real buildings and UFH.

 

Our first self build, standard building regs 20 years ago, nothing special, had UFH on the landing, because the designer said so. That circuit NEVER turned on.  Plenty of heat coming up the stairs from below.  Even the downstairs hall rarely came on because there was so little external wall to leak heat, and plenty of heat from other downstairs rooms.

 

Our present house, finished 2 years ago now, to better than building regs insulation and air tightness, has no UFH loop in the hall and only short loops in the bathroom and en-suite.  No other heating at all upstairs, it gets all the heat it needs from downstairs.  Unless of course you particularly want a very hot bedroom.

[iMCaan]

Thank you for the comments/suggestions.

 

There's no ASHP. We'll be using a boiler and a hot water cylinder.

 

The GF and FF are beam and block so heat rising from downstairs to FF will be blocked or kept to minimal by B&B. 

A bit naive/inexperience to got with B&B FF but it's fitted now.

 

I just feel that if I don't use zoning there we'll be unnecessary heating empty rooms when kids are out.

I suppose the heating in bedrooms can be turned off/down during when not required?

 

 

 

[JohnMo]

1 minute ago, iMCaan said:

don't use zoning there we'll be unnecessary heating empty rooms when kids are out

UFH could take several hours to get a meaningful room temp change. So dream on if you think UFH is an on or off magic button. If you want that, you need high temp radiators, but not sure current building regs allow that, as everything is supposed to heat pump ready. Even with a gas boiler to get good efficiency you need low flow temperatures.

 

I got a completion certificate in March, had used the gas boiler for two heating seasons, have just installed an ASHP, mostly for cooling, but the heating should be cheaper also than gas. Cylinder prices are about the same for gas or heat pump, plumbing about the same, good boiler that does weather compensation and ASHP are about the same cost.

[ProDave]

Who is / has designed the house?  What are you hoping to achieve, just to pass building regs or the lowest energy most efficient build you can?  Has a proper heat loss calculation been done?

 

If nothing else, upstairs will need less heat than downstairs so you could fir the upstairs loops to a wider pipe spacing.

[iMCaan]

I've not had the best of any trade so far inc architects, could say I'm a victim of cowboys. Architect(s) designed it (long story, many years long) but I've not had much input. 

Probably, people took advantage of my naivety/inexperience.

 

We had the SAP calculations report done.

 

I'm looking for a most efficient build but within a tight budget as the build is over a year overdue, which has eaten up a lot of my budget 

 

I did initially consider ASHP and solar panels but can't now with the limited budget 

 

What is the widest pipe spacing that can be used?

 

 

[JohnMo]

4 hours ago, iMCaan said:

What is the widest pipe spacing that can be used?

I am at 300mm, but I am a brave (or foolish). You need good floor installation for that wide and low overall heat loss. Generally 200mm would be fine, but really depends on your heat loss figures. You don't want to be flowing more than 35 deg on the very coldest day (for me that's -9).

[Dave Jones]

18 hours ago, iMCaan said:

 

 

The GF and FF are beam and block so heat rising from downstairs to FF will be blocked or kept to minimal by B&B. 

 

 

what makes you think that ?

 

The whole house should be (and is required to be by SAP) surrounded by a continuous insulated box with minimal cold bridges. Just heating a corner of that box will reduce efficiency and cost you more for no net gain hence zoning in boxes is pointless. 

 

Why the massive hassle and expense of block and beam for first floor ? Planning  to park cars on it ?

 

You wall construction looks like 300mm, that's going to cost you in expensive insulation and labour time to correctly (they wont)detail it. Have you already got building regs ? Have you got construction drawings ? 

 

 

The more you simplify the whole build the better chance you have of getting it built correctly quicker and not costing you both kidneys.

Edited September 13, 2023 by Dave Jones

[iMCaan]

6 minutes ago, Dave Jones said:

what makes you think that ?

The thickness of first floor structure, plasterboard, blocks, 25mm insulation, 50mm screed and floor covering (tiles likely). 

 

16 minutes ago, Dave Jones said:

The whole house should be (and is required to be my SAP) surrounded by a continuous insulated box with minimal cold bridges. Just heating a corner of that box will reduce efficiency and cost you more for no net gain hence zoning in boxes is pointless. 

A lot of people here are suggesting no UFH on first floor and no zoning to save cost. I will take this on board and discuss this with my other half.

 

1 hour ago, Dave Jones said:

Why the massive hassle and expense of block and beam for first floor ? Planning  to park cars on it ?

Inexperience. We wanted to build the house quickly and install UFH on the first floor. Nobody, from architect to the builder, advised us against B&B on first floor.

 

1 hour ago, Dave Jones said:

The more you simplify the whole build the better chance you have of getting it built correctly quicker and not costing you both kidneys.

So much for the quick build, almost 2 years from starting site clearing to just starting roofing. The architect took a few years to design the house and still messed up the levels then eventually decided to go with another architect. The rise of material prices over the past couple of years and scaffolding (has been up for over a year now) cost has eaten a large chunk of my budget.  Not had the best of experience with anybody yet. 

 

The best advice/help I've had is from buildhub community. Thank you Buildhub community.

 

 

 

 

[joth]

36 minutes ago, iMCaan said:

A lot of people here are suggesting no UFH on first floor and no zoning to save cost. I will take this on board and discuss this with my other half.

 

Just to call out one thing here in case it's not obvious: even if you run the UFH as a single zone, you'll still want to install it as multiple loops in order to ensure a good heat distribution. Those loops may as well be laid out according to the room layout, both because it's topologically simpler to run it that way, and also because it gives you a very simple path to add zone control in future if you ever find you need it.

This is what I did: 100m2 GF of UFH (no heating upstairs). most of GF is one big open plan area, but the snug is well divided off and naturally maintains a different temperature. When I had a guest stay over in the snug they found it far too hot for sleeping, so it was very easy to manually close off the loops to that room to avoid it getting hotter. I've since added manifold actuators and use zoning to avoid individual rooms overshooting temperature, but no room can "call for heat" on its own therefore avoid the inefficiency of zoning that causes all the concern here. It just limits the max temp.

 

[Dave Jones]

47 minutes ago, iMCaan said:

The thickness of first floor structure, plasterboard, blocks, 25mm insulation, 50mm screed and floor covering (tiles likely). 

 

A lot of people here are suggesting no UFH on first floor and no zoning to save cost. I will take this on board and discuss this with my other half.

 

Inexperience. We wanted to build the house quickly and install UFH on the first floor. Nobody, from architect to the builder, advised us against B&B on first floor.

 

So much for the quick build, almost 2 years from starting site clearing to just starting roofing. The architect took a few years to design the house and still messed up the levels then eventually decided to go with another architect. The rise of material prices over the past couple of years and scaffolding (has been up for over a year now) cost has eaten a large chunk of my budget.  Not had the best of experience with anybody yet. 

 

The best advice/help I've had is from buildhub community. Thank you Buildhub community.

 

 

 

 

 

Construction drawings ?

 

What stage of the build you at ?

[iMCaan]

Drawings attached.

 

The roofer has started slating the roof today. He reckons it'll take him 3/4 weeks.

[iMCaan]

You wall construction looks like 300mm, that's going to cost you in expensive insulation and labour time to correctly (they wont)detail it. Have you already got building regs ? 

Yes, 300mm cavity wall. 50mm Kingspan insulation in cavity wall. Also, 50mm insulation in internal cavity wall adjoining garage, which builder said I don't need but I still went ahead with it.

Building control officer is happy with everything so far.

Edited September 13, 2023 by iMCaan

[iMCaan]

2 hours ago, joth said:

I've since added manifold actuators and use zoning to avoid individual rooms overshooting temperature, but no room can "call for heat" on its own therefore avoid the inefficiency of zoning that causes all the concern here. It just limits the max temp.

What do you mean by "no room can "call for heat" on its own"? If there are two rooms and each room is a zone, then both rooms/zones can call hot water/heat as and when needed to maintain the different temperature set for each room?

[joth]

19 minutes ago, iMCaan said:

Yes, 300mm cavity wall. 50mm Kingspan insulation in cavity wall. Also, 50mm insulation in internal cavity wall adjoining garage, which builder said I don't need but I still went ahead with it.

Building control officer is happy with everything so far.

 

This sounds unlikely: 50mm PIR on its own cannot meet current (or any recent) building regs. The roof has 160mm (100mm between joists and 60mm continuous under it) which sounds more plausible for a BR grade of build.

What do you have under the ground floor?

Edited September 13, 2023 by joth

[Mr Punter]

12 minutes ago, iMCaan said:

Yes, correct 300mm cavity wall. 50mm Kingspan insulation in cavity wall.

 

WHAT???

 

Did you get a design stage SAP?  You will need it for Building regs.  50mm Kingspan will not be acceptable.  This may have been OK 20 years ago.

[joth]

3 minutes ago, iMCaan said:

What do you mean by "no room can "call for heat" on its own"? If there are two rooms and each room is a zone, then both rooms/zones can call hot water/heat as and when needed to maintain the different temperature set for each room?

In essence the ASHP only runs when the whole house average temp gets low enough to need heating. Not when any single room is below temp.

(It's slightly more complex as I boost the whole lot during the overnight cheaprate, but that's just a case of moving the setpoint for the whole house average).

 

(I manage it with Loxone so have much finer grained control than conventional heating controls. Also the per-zone cost is lower, as the temperature sensors are already in the light switches anyway, and no need for any per-room key pads or wiring etc)

 

[iMCaan]

17 minutes ago, Mr Punter said:

 

WHAT???

 

Did you get a design stage SAP?  You will need it for Building regs.  50mm Kingspan will not be acceptable.  This may have been OK 20 years ago.

This is normal up in West Yorkshire. I am aware of another new build 2022 completion, also used 50mm insulation in cavity walls.

 

100mm block, 50mm insulation, 50mm void and 100mm stone.

 

 

Thanks joth, aren't you using a hot water cylinder? I thought the ASHP will come on to heat the hot water cylinder when it falls below set temp.? I need to read up on ASHP.

Edited September 13, 2023 by iMCaan

[joth]

 

8 minutes ago, iMCaan said:

This is normal up in West Yorkshire. I am aware of another new build 2022 completion, also used 50mm insulation in cavity walls.

 

 

But "Normal" does not necessarily mean good (or even legal for that matter). What is the EPC of that other build, and how much are they actually spending on heating?

 

The advice on this forum is generally predicated on the assumption that if you're building your own house, you want to do a (very) good job of it. Much better than BR minimum. It's what is called the "fabric first" approach. Unless the fabric of the building is good, all the other advice here built on it is not likely to work out so well.

You either need to change tact to build a high quality building, concentrating on thermal bridge free insulation, airtightness and actively managed ventilation, or stick to normal build with the normal received wisdom on heating. If going the latter route it would mean keep the FF UFH, keeping the zoning, keep with the gas boiler.

 

 

30 minutes ago, iMCaan said:

100mm block, 50mm insulation, 50mm void and 100mm stone.

What U-value does your SAP report say this is? How about the floors and roof? Have you had anyone draw up a room by room heat loss calculation? Or you can do this yourself using the calculator on here

 

 

[Adrian Walker]

On 12/09/2023 at 12:30, Lofty718 said:

UFH should not be zoned at all and kept as open loop as possible. One zone upstairs one zone downstairs

 

I agree, you want the whole house to be the same temperature.  If rooms are at different temperatures it will cause a draft between them.

[Adsibob]

8 minutes ago, Adrian Walker said:

 

I agree, you want the whole house to be the same temperature.  If rooms are at different temperatures it will cause a draft between them.

This is just not true. At least not in an airtight house. It also makes no sense to have sleeping quarters the same temp as say, your lounge and kitchen. Sleeping quarters are more comfortable at 18C (+/- 1C), whereas that would be far too cold for a living room, dining roo, bathroom or kitchen.

[ProDave]

25 minutes ago, Adsibob said:

This is just not true. At least not in an airtight house. It also makes no sense to have sleeping quarters the same temp as say, your lounge and kitchen. Sleeping quarters are more comfortable at 18C (+/- 1C), whereas that would be far too cold for a living room, dining roo, bathroom or kitchen.

And we achieve that with no heating upstairs.  If we had heating upstairs and set the upstairs thermostat to 18C it would never turn on.  If bedroom gets too hot we open a window to let heat out.