Anyone with an MBC Timber Frame that has (or is aiming for) PassivHaus certification?

[Kevin Dawson]

We're committed and en route down this road/rabbbit warren and would love to be able to sanity check the journey with anyone who's either been there, done that or is already on the same road.

 

For reference - approx 200sqm TFA (circa 20m x 7m externally), two storey (upside down), MBC Passive TF with insulated slab, exterior to be vertically clad in larch (aside from the bottom 50cm which will be stone walling).  Nilan Compact PXL MVHR with LG ASHP. Location Somerset.

 

Thank in advance.

 

 

[JohnMo]

  On 07/09/2024 at 14:23, Kevin Dawson said:

Nilan Compact PXL MVHR

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And an ASHP - why.

 

Keep systems separate, ventilation keep to ventilation, heating keep to heating. So a normal MVHR unit, a normal monobloc heat pump.

 

If you have a choice of heat pump, go Panasonic. 

 

Go Heat Geek cylinder (300L) you should be able to get a CoP of around 5 compared to the 3.5 I get with a more normal 3m² coil heat pump cylinder.

 

UFH on ground floor and fan coils in bedrooms all as a single zone. 

[MikeSharp01]

  On 07/09/2024 at 15:01, JohnMo said:

If you have a choice of heat pump, go Panasonic. 

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Why? I looked at Panasonic and the information on their R32 5kW monoblock was limited or very old - I could find nothing on how to get access to the controller although it talks about a cloud option I don't want that - local RS485 would suit me much better and the sound levels seemed a bit high.

[JohnMo]

  On 07/09/2024 at 15:41, MikeSharp01 said:

Why

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Everything I have read or heard about them says they are good. Work well out the box. Seems to give a very CoP with little effort.

 

A few on here use then @Nickfromwales sang their praises also.

[MikeSharp01]

  On 07/09/2024 at 15:46, JohnMo said:

A few on here use then @Nickfromwales sang their praises also.

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Speaking of @Nickfromwales looks like he has not been on here since July - must be having a good  long holiday somewhere let's hope.

[MikeSharp01]

  On 07/09/2024 at 16:17, MikeSharp01 said:

Speaking of @Nickfromwales looks like he has not been on here since July - must be having a good  long holiday somewhere let's hope.

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Actually - belay that a little birdie tells me he was lurking on the side last Monday - clearly we must be doing alright otherwise he would have been on to put us straight wouldn't he.

[Kevin Dawson]

  On 07/09/2024 at 15:01, JohnMo said:

And an ASHP - why.

 

Keep systems separate, ventilation keep to ventilation, heating keep to heating. So a normal MVHR unit, a normal monobloc heat pump.

 

If you have a choice of heat pump, go Panasonic. 

 

Go Heat Geek cylinder (300L) you should be able to get a CoP of around 5 compared to the 3.5 I get with a more normal 3m² coil heat pump cylinder.

 

UFH on ground floor and fan coils in bedrooms all as a single zone. 

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We're not fitting the Nilan Air 9 ASHP at this time - the Compact P provides 180litre DHW and MVHR, the LG (MU3R19.U22) provides heating & cooling as necessary (5.3kW with a spec'd COP of 5.0).  We have multi-zone UFH pipes screened into the GF slab but will suck it and see initially before deciding whether to fire them up as this is the bedroom floor (living space is upstairs).  Watch this space as they say.

[JohnMo]

  On 07/09/2024 at 16:56, Kevin Dawson said:

Compact P provides 180litre DHW and MVHR, the LG (MU3R19.U22) provides heating & cooling

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That was my point, why bother getting two heat pumps, when LG will do both hot water and cool or heat. Seems like you are spending twice.

[Nickfromwales]

  On 07/09/2024 at 16:17, MikeSharp01 said:

Speaking of @Nickfromwales looks like he has not been on here since July - must be having a good  long holiday somewhere let's hope.

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Long bloody work holiday lol. I apologise sincerely boss!

[Nickfromwales]

  On 07/09/2024 at 16:24, MikeSharp01 said:

Actually - belay that a little birdie tells me he was lurking on the side last Monday - clearly we must be doing alright otherwise he would have been on to put us straight wouldn't he.

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[Nickfromwales]

  On 07/09/2024 at 15:46, JohnMo said:

Everything I have read or heard about them says they are good. Work well out the box. Seems to give a very CoP with little effort.

 

A few on here use then @Nickfromwales sang their praises also.

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Yup, that is correct. Cheaper than shoplifting, quiet as a mouse farting in a church on a Sunday during mass, and solid as a rock.

[MikeSharp01]

  On 07/09/2024 at 20:04, Nickfromwales said:

  On 07/09/2024 at 15:46, JohnMo said:

their praises also.

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Yup, that is correct. Cheaper than shoplifting, quiet as a mouse farting in a church on a Sunday during mass, and solid as a rock.

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But how do you automate their controls - cannot find any manuals or datasheets and the specifications were all written in 2017 and you cannot be telling me that the world of ASHPs has not moved on a long way or that the 2017 design was 10 years ahead of the pack.

[JohnMo]

  On 07/09/2024 at 21:29, MikeSharp01 said:

But how do you automate their controls

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Why do the controls need automating?

Heat pump are a low and slow machine, best left to their own devises. Set a WC curve fine time the running parameters if needed, then leave them too it.

 

The more fiddling from outside the more they cost to run. 

[PNAmble]

  On 07/09/2024 at 15:01, JohnMo said:

UFH on ground floor and fan coils in bedrooms all as a single zone.

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He’s building an upside down house.  Why would this be the answer?  I’ve just finished building a passive standard upside down house and the last thing I’d want is UFH in the bedrooms.  Sometimes ‘your best solution’ isn’t everyone’s best solution.  

[PNAmble]

  On 07/09/2024 at 16:56, Kevin Dawson said:

We have multi-zone UFH pipes screened into the GF slab but will suck it and see initially before deciding whether to fire them up as this is the bedroom floor (living space is upstairs).  Watch this space as they say.

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I’ve just completed an upside down passive standard house.  put a few radiators in running at 37/35 @ -3.  Will find out during winter if all ok, but full modelling shows it will work.   Very happy that the expectation is that the bedroom floor tracks about a degree less than the living floor. 

[Kevin Dawson]

  On 07/09/2024 at 22:45, PNAmble said:

I’ve just completed an upside down passive standard house.  put a few radiators in running at 37/35 @ -3.  Will find out during winter if all ok, but full modelling shows it will work.   Very happy that the expectation is that the bedroom floor tracks about a degree less than the living floor. 

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Good to know - and if needed, with the UFH zones we've laid in we'll be able to warm the entrance hall/stairwell and en suites for some extra warmth whilst still leaving the bedrooms off.  Fingers crossed.

[Kevin Dawson]

  On 07/09/2024 at 18:02, JohnMo said:

That was my point, why bother getting two heat pumps, when LG will do both hot water and cool or heat. Seems like you are spending twice.

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Technically yes but the (small) heat pump in the Compact 9 is primarily there to manage domestic hot water production (integral 180l tank) with some residual ability to manage air temperature up or down as appropriate and in an ideal world should be all we need.  However, given the heat load and TFA the modelling showed we'd also need either the Air 9 ASHP or the LG and the LG gave us a bit more flexibility with its indoor heating/cooling ducts.

[zzPaulzz]

  On 07/09/2024 at 14:23, Kevin Dawson said:

We're committed and en route down this road/rabbbit warren and would love to be able to sanity check the journey with anyone who's either been there, done that or is already on the same road.

 

For reference - approx 200sqm TFA (circa 20m x 7m externally), two storey (upside down), MBC Passive TF with insulated slab, exterior to be vertically clad in larch (aside from the bottom 50cm which will be stone walling).  Nilan Compact PXL MVHR with LG ASHP. Location Somerset.

 

Thank in advance.

 

 

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@Kevin Dawson About to embark down the same road as you. Two story new build in Suffolk with a TFA of 180m2.  I’m struggling to make a choice between MBC Twin Wall, their Hi Performance, or a KTS Ultima/TEK system. KTS Ultima wins on price, but seems have thermal bridging issues around windows. MBC Twin Wall is about £30k more but has excellent performance all around. MBC High Performance has the same thermal bridging issues as KTS but is not much less than the Passive Frame once extra costs to get to the passive air tightness standard.  How did you make your decision? 

[JohnMo]

  On 07/09/2024 at 22:34, PNAmble said:

He’s building an upside down house.  Why would this be the answer? 

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Obviously I missed the point of upside down. I have UFH in the bedrooms, but doing it again, as I said fan coils would be better.  Main living space UFH is good, generally cheap to run especially with a heat pump

 

  On 07/09/2024 at 16:56, Kevin Dawson said:

We have multi-zone

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I started that way and it was a disaster. Low energy houses already place a strain on the control system of any heat source, split the house further to small heating zones just leads to short cycling and or a buffer and rubbish CoP without very careful design. One zone, no mixers or additional pumps, saves money, improves performance, makes it all easy.

[MikeSharp01]

  On 07/09/2024 at 21:55, JohnMo said:

Why do the controls need automating?

Heat pump are a low and slow machine, best left to their own devises.

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It's all about optimisation in the end.

[Benpointer]

  On 08/09/2024 at 18:51, JohnMo said:

  On 07/09/2024 at 16:56, Kevin Dawson said:

We have multi-zone UFH ...

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I started that way and it was a disaster. Low energy houses already place a strain on the control system of any heat source, split the house further to small heating zones just leads to short cycling and or a buffer and rubbish CoP without very careful design. One zone, no mixers or additional pumps, saves money, improves performance, makes it all easy.

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Interesting.  We have multi-zone UFH in our current house and plan to do the same in our forthcoming new build.  We like the en-suite in particular to be warmer (23°C) than the bedroom (18°C) or the living areas (21°C).  I can't see why we'd want the whole house to be the same temperature.

[garrymartin]

  On 08/09/2024 at 20:19, Benpointer said:

 

Interesting.  We have multi-zone UFH in our current house and plan to do the same in our forthcoming new build.  We like the en-suite in particular to be warmer (23°C) than the bedroom (18°C) or the living areas (21°C).  I can't see why we'd want the whole house to be the same temperature.

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Most of the people who discuss a single ground-floor UFH zone will combine that with electric underfloor heating or electric towel rails (or both) in first floor en-suites and bathrooms, and perhaps fan coils in the first-floor bedrooms.

[PNAmble]

  On 08/09/2024 at 20:19, Benpointer said:

We like the en-suite in particular to be warmer (23°C) than the bedroom (18°C) or the living areas (21°C).  I can't see why we'd want the whole house to be the same temperature.

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one of the things with a passivhaus ‘style’ house is that once its operating the temps are the same throughout the house. Probably a degree different across rooms (upside down house), whilst you manage solar gain etc.  our downstairs north facing bedrooms track very similar to our living area.  
 

[PNAmble]

  On 08/09/2024 at 18:51, JohnMo said:

Obviously I missed the point of upside down. I have UFH in the bedrooms, but doing it again, as I said fan coils would be better.  Main living space UFH is good, generally cheap to run especially with a heat pump

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So. Horses for courses. Read the question and don’t assume your solution is perfect for everyone, an upside down house is very different than the  bog standard ‘x up’ ‘x down’ built on a flat plot. 

[JohnMo]

  On 08/09/2024 at 20:19, Benpointer said:

can't see why we'd want the whole house to be the same temperature.

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That's just it, you don't need it the same temperature everywhere.  You can if you want, but our bedrooms are generally cooler than the living space, because we add less heat in the bedrooms, our ensuite warmer than the bedroom because we have additional heat in there, or as best you can in the same space.

 

It's called balancing the heating system. Part of the basic system design. If you want the house the same temperature leave the interiors open an hour or two, it will mostly even out (even on an upside down house, single storey or x up x down house) if don't want even temps keep the doors closed.

 

  On 08/09/2024 at 21:17, PNAmble said:

upside down house is very different than the  bog standard ‘x up’ ‘x down’ built on a flat plot.

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Very different (?) because you heat the top and heat stays there to a large degree. But nothing really special going on. So your bedroom are a degree cooler, good for you.

 

  On 08/09/2024 at 21:17, PNAmble said:

Read the question and don’t assume your solution is perfect for everyone

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Mine isn't the perfect solution, neither is yours. It for the OP to ask questions dismiss or include whatever he wants, it's their money, their choice. 

 

@PNAmble are you the thread police, or just a grumpy person. Difficult to tell.