Panasonic aquarea - dual zone cooling @ diff temps possible?

[JohnMo]

23 minutes ago, -rick- said:

 

Ah, trying to make something that wasn't designed for it do cooling. I thought we were talking about things that did support it but the manufacturer didn't recommend.

Not actually come across any GSHP that do cooling out the box, Nebe have a super expensive add on kit for it, but not seen anything else.

 

12 hours ago, SimonD said:

ground source required so much additional plant and complexity, it was ridiculous - e.g. borehole  min 150m deep not ground loop and additional air batteries together with a hydronic design utilising a volumiser and the dhw cylinder to dump excess heat

I suspect all this comes about as they as they not reversible - so instead of adding the functionality to the GSHP box, they add it externally via a load complication. Not really thinking inside the box they are literally thinking outside the box.

[SimonD]

5 minutes ago, JohnMo said:

Nebe have a super expensive add on kit for it, but not seen anything else.

 Nibe is one manufacturer who makes a distinction between active and passive cooling  - they have what they call a 2 pipe system for passive and a 4-pipe system for active. It's the active system that has the expensive add on kit where iirc the passive one is marginal. I can't remember if you can access the schematics openly or whether you've got to be Nibe Pro to access them, but it's all available.

 

Nibe is one manufacturer who doesn't seem to shrug their shoulders regarding cooling but is careful to advise on proper system design.

[SimonD]

1 hour ago, -rick- said:

f you use a GS heat pump to cool a property the heatpump is actively heating the ground during this time. The problems with ground source I thought were more with the ground freezing when you try to pull too much heat from it during winter. Didn't think adding heat to the ground during summer was a big issue comparitively.

 

This is what I thought too. And I thought that using cooling could be advantageous to recharge the soil for the next winter. However, it was explained to me that the ground loop system can't take the quantity of heat dumped into it which therefore reduces the hp cooling capacity. Apparently the borehole solution can take the dumped heat.

 

You don't see the same behaviour with ashp of course because it's dumping the heat to the atmosphere and you're limited to the units ability to transfer the heat. This is why you might employ an air battery such as a fan coil unit to assist the gshp to dump heat outside the ground.

 

Tbh, modelling the thermal behaviour of the ground is beyond my knowledge at the moment, so I'm kind of accepting their wisdom in this until I see some evidence to the contrary.

[SimonD]

2 hours ago, jack said:

I've used underfloor cooling for nearly 10 years (didn't use it the first two or three years after we moved in) with great success and zero issues.

 

Panasonic's UK technical team were hugely supportive while I was trying to get the ASHP working efficiently in UFH mode, but they were very cold (pardon the pun) on the idea of underfloor cooling. I think there's just a strong bias in the undustry against it, probably due to a combination of risk-aversion and ignorance.

 Absolutely. I've just completed an installation with a new ashp and when commissioning the thing I found some new stuff within the control software and some behaviour of the system that wasn't covered anywhere in the manuals. So I made my list of questions, called up technical support and in a tone that suggested they though I was an idiot, they told me that what I was asking either wasn't possible or wasn't implemented - but I played with it anyway and my tests show that what they told me was incorrect. It's not the only time tech support have told me the wrong thing even with Gas boilers and controls.

 

I think the nature of this forum is that we're happy to push the boundaries and take some risks whereas the manufacturers have to cover their backs, just as I do with a system installation.  You know you have to when you try to explain system flow temperature and they look at the thermostat quizzically telling you that it says 21....not 55

[-rick-]

53 minutes ago, SimonD said:

This is what I thought too. And I thought that using cooling could be advantageous to recharge the soil for the next winter. However, it was explained to me that the ground loop system can't take the quantity of heat dumped into it which therefore reduces the hp cooling capacity. Apparently the borehole solution can take the dumped heat.

 

This doesn't really match what I've seen before (though again it's been a while). I suspect this is a case where they are thinking aircon not cooling and designing for the 'cool a hot room down rapidly' type situation with all its other complications.

[SBMS]

14 hours ago, JohnMo said:

is just complexity for the sake of it.

I’m not doing it for the sake of it and I really don’t follow this logic - I don’t know where summers and temperatures will be in ten years - and I don’t know exactly how the house will respond to summer temperatures until I’ve actually built and lived in it. Why the aversion to a proposed system that can do exactly what you suggest (run at above dew point) but also have the capability to run lower for the sake of a mixer valve and temperature sensor? 

 

I can’t understand why future proofing in most contexts is seen as a good thing by self builders but I seem to be proposing heresy here in giving more flexibility 🤷‍♂️

Edited October 17 by SBMS

[Gus Potter]

On 17/10/2025 at 00:09, SimonD said:

From the perspective of using heating circuits for cooling with heatpumps, both air source and ground source, it seems to be on trend at the moment and I have to admit I was sucked into this.

Ok, so put it another way, it looks good. 30 years ago I started experimenting with UFH. It looked good and my first system worked, it was fantastic, to have the luxury of warm floors, no radiators., freed up wall space. But it wasn't perfect when compared to what I know now! But hey ho, I built it with a basic mixer valve, an oil fired boiler and it was installed in a house that had U values much higher than what we are seeking to achieve in this day and age. 

 

So my philistine hat back on. What you bury in the floor must have redundancy, be over designed. At the back of my mind is that ASHP etc may be able to run on lower temperatures in the future, so the pipes in the floor you can't change, we need lots of redundancy in terms of flow capacity, and if the pipes get a bit clogged,  but the plant above the floor can be changed. 

 

Think of UFH in terms of the cost of a car which need servicing and eventual replacement and that the pipes in the floor are your forever home. Design the pipes too tight and a home valuer will right the value of your property down! Surveyors are clocking this potential liability so don't say I'm not warning you!

 

Think about maintenance costs! It's great to talk about the thoery if you don't have top pick up the bill in 3 - 5 years time when the parts start to get sticky and weep water!

 

I'll say again.. is there anyone here on BH that is thinking about this.. or is it just me. 

 

OK I'm going to take my philistine hat off and put my toe in the wacky techy water!

 

In the old days we had wall thermostats that worked on a bimetalic strip. The hysteresis was, a bit blunt, incedentally I used to rear Pheasants and built my own incubators, these needs tighter control. 

 

So now we have lots of more precise data. I work from home and if I use the oven the temperature graphs spike, if I leave the door open between the highly insulated part of the house and the old house the graph changes again. If the sun comes out as it did the other day for a short time the room temperature rise. 

 

I shit you not Sherlock, I don't have weather compensation as I can look at the weather forecast! So can anyone tell me how weather compensation copes with this and rugs on the floor? Also if you put 4 - 6 people in a room it heats up.. explain please! Also, say yoiu have a bath and the room gets hot, you open the doors and all that heat comes out. 

 

To my mind an ASHP or good UFH system should just look after it's self, not cost a lot to maintain. 

 

If you want to cool stuff then you have two basic choices.

 

Open the windows and doors if the temperature outside is less. If more then you need to be able to cool floors, the furniture and beds quickly and that justiufy my appraoch to over designing the pipes under the floors. 

 

Come on teckies.. lets see your costs curve for long term maintanace performance, how you cool a floor fast..given the above.. sorry it's just me being practical. 

On 17/10/2025 at 08:51, JohnMo said:

Our first year in the house, mid summer the water in floor was at 24 degs. Our house just stayed

In an ideal world in the UK we don't want to spend money cooling a house. 

 

I'm also a big fan of passive stack ventilation, story for another day. 

 

The UK is an island, I grew up in Africa where the climate is different. The UK climate is something that we should enjoy and learn to live with. 

 

Here is my roughed out UF that I built just to keep the house warm while I was doing the work. It's gate valves from Screwfix, Youkshire fitting for the manifold, but the blender valve is expensive. I'm a bit behind with the work but this has been working ok for the last few years. 

 

 

 

I have a new gas condensing boiler installed roughly at the same time as my DIY manifold, Valliant. Just mid range. 

 

Anyway I know lots of folk are tacky. So if you are on a budget. Spend lots and build in redundancy into your pipes buried in the concrete. leave a bit of space so you can change the boiler, manifolds as technology advances. Have fun and remember when we meet in heaven I'm not a crusty in real life!

 

Edited Sunday at 20:59 by Gus Potter

[Gus Potter]

On 17/10/2025 at 13:47, SimonD said:

 Absolutely. I've just completed an installation with a new ashp and when commissioning the thing I found some new stuff within the control software and some behaviour of the system that wasn't covered anywhere in the manuals.

So I just picked this bit out of you post. If it's hard now imagine how folk are going to maintain this in 5 years time? 

[Gus Potter]

On 14/10/2025 at 22:22, JohnMo said:

In most of the UK if you never allow house to overheat, you run at about 13 degs without any condensation issues.

This is not practicable achievable in my 30 years experience. The UK weather is very unpredictable. At times UFH just won't comply, so you open a window or a door!

 

What we should be doing here is saying.. hey, UFH is not perfect, we will never make it perfect but here is how you can get the best out of it for minimal maintanace and running cost.

 

I'll say this again and again, you can design on paper, balance your system and it will work for a few months and the game changes! 

 

 

It's fine if you have all the time in the world to play with your UFH system but lots of folk have families, kids and a day job!

 

On 17/10/2025 at 11:29, jack said:

I've used underfloor cooling for nearly 10 years

Ok interested, where do you live, what are you pipe centres, how much have your maintanence costs been over the last ten years

 

[jack]

10 hours ago, Gus Potter said:

Ok interested, where do you live, what are you pipe centres, how much have your maintanence costs been over the last ten years

 

Southeast, 200 mm centres (MBC passive slab).

 

What would you expect for maintenance costs? Except for replacing a failed control board on the ASHP about three years in, I haven't spent a penny on anything other than electricity.

 

I've recently been thinking about seeing whether I ought to replace the water/glycol in the system. I assume it has a life expectancy.

[jack]

11 hours ago, Gus Potter said:

I'll say this again and again, you can design on paper, balance your system and it will work for a few months and the game changes! 

 

It's fine if you have all the time in the world to play with your UFH system but lots of folk have families, kids and a day job!

 

I can't tell you how utterly removed this is from my own experience. I don't change a single setting on my UFH, irrespective of whether it's in heating or cooling mode.

 

I'm sure some of the control tweaks I've set up in my home automation system help (particularly with costs), but I'm pretty confident I could get similar results in terms of house comfort with a thermostat or two and a timer.

 

I do think that high levels of insulation and heating the structural slab makes a big difference.

[SimonD]

10 hours ago, Gus Potter said:

Think about maintenance costs! It's great to talk about the thoery if you don't have top pick up the bill in 3 - 5 years time when the parts start to get sticky and weep water!

 

I think this comes down to product choice at the start. I've recently completed 2 repairs to UFH systems in houses built within the last 10 years. The systems used different manufacturers but in each of those systems one manufacturer had completely withdrawn from UFH and the other had completely redesigned its system and no older parts were available.

 

The industry is partly to blame here, of course

11 hours ago, Gus Potter said:

So can anyone tell me how weather compensation copes with this and rugs on the floor? Also if you put 4 - 6 people in a room it heats up..

 

You don't use pure weather compensation but also use a room thermostat that provides load compensation.

 

The problem is response time inherent in ufh systems, so you'll always get inertia.

 

I have specifically chosen to use radiators as they provide a more response system.

 

Like you say, when you're busy with work and family and everything else life throws at you, you can't be spending everyday planning for weather and temp changes and tinkering with the system. But this should be dealt with at commissioning stage after which the system shouldn't need touching. 

 

11 hours ago, Gus Potter said:

So I just picked this bit out of you post. If it's hard now imagine how folk are going to maintain this in 5 years time? 

 

My worry is more about long term support from the manufacturers and the inclination now to take everything online and start to charge subscription fees.

 

Once a system is set up and commissioned properly, it should take care of itself.  

[JohnMo]

11 hours ago, Gus Potter said:

Ok interested, where do you live, what are you pipe centres, how much have your maintanence costs been over the last ten years

300mm centres but no pipe under fixed kitchen units, or under beds (whole house designed around views, so unlikely that rooms will be moved much over time) no dedicated loops in hall, utility, so approx 600m pipe buried in 192m² of floor. System only been running for 4 years.

 

Not expecting any maintenance costs, nothing is moved in the system all flow meters except one are fully open on manifold, no actuators on manifold, no zone valves, pumps or mixers to go wrong.

 

 

Edited Monday at 08:39 by JohnMo

[JamesPa]

2 hours ago, JohnMo said:

Not expecting any maintenance costs, nothing is moved in the system all flow meters except one are fully open on manifold, no actuators on manifold, no zone valves, pumps or mixers to go wrong.

Well that's no good then, how do you expect the heating controls industry to make any money if you exclude all of the irrelevant components that are also most likely to break down?

 

Obviously that comment was slightly tongue in cheek but at the same time it's worth bearing in mind that the controls industry is inevitably motivated by selling controls, not by our comfort or cost effectiveness. 

 

IMHO (and experience with my own heating system) we have been somewhat brainwashed into micro control over past years and the transition to heat pumps is exposing the futility of this approach.

Edited Monday at 11:22 by JamesPa

[SimonD]

40 minutes ago, JamesPa said:

we have been somewhat brainwashed into micro control over past years and the transition to heat pumps is exposing the futility of this approach.

 

Don't hold your breath there are still schematics abound for HP systems for micro zoning with thermostats in every room. Vaillant have a few that include 3rd party controls too. According to the powers at be, this is what customers want... so the brainwashing continues.

 

I wonder whether Heat Geek zero disrupt cheap version includes keeping any micro zoned systems or whether they'll propose chucking it all in the bin?

 

Personally, I'm counting my blessings I don't have to deal with 3rd party controls any more...

[Gus Potter]

On 20/10/2025 at 08:45, jack said:

I can't tell you how utterly removed this is from my own experience. I don't change a single setting on my UFH, irrespective of whether it's in heating or cooling mode.

That's great news Jack. Your heating system is something that we should aim to achieve. 

 

But.. you are a switched on fellow with loads of life experience. My guess is that you controlled your design,  built well and are thus reaping the rewards. 

 

Unfortunately the build market is full of chancers, designers included!

On 20/10/2025 at 12:15, JamesPa said:

IMHO (and experience with my own heating system) we have been somewhat brainwashed into micro control over past years and the transition to heat pumps is exposing the futility of this approach

I rest my case.

 

On 17/10/2025 at 22:58, SBMS said:

I don’t know where summers and temperatures will be in ten years - and I don’t know exactly how the house will respond to summer temperatures until I’ve actually built and lived in it.

Again I rest. 

 

On 20/10/2025 at 09:37, JohnMo said:

Not expecting any maintenance costs, nothing is moved in the system all flow meters except one are fully open on manifold, no actuators on manifold, no zone valves, pumps or mixers to go wrong.

John, I love your technical input, learn lots from you so thanks for that. It's ok to disagree. My main arguement is not about UFH in principle, or about your well presented and knowlegeable approach. 

 

 My main point is to design in redundancy where pipes are buried in screed / concrete and recognise that your house, to maintain it's value, has to perform and not be a burden to maintain when you sell it on. 

 

For all BH folk. This is something you really need to face up to as surveyors can right down the value of your property. The more main stream UFH becomes.. and the more that the big developers cock it up, which they will, the more the light is going to shine on the self build UFH market. 

 

Now UFH, controls, home automation are a lively topic on BH. I like to see it as folk are innovating which is great, call it a bit of a hobby. But don't expect me as a designer who is responsible for my Client's money and have a Civic responsibility to the next person that will buy your house to not ask some nasty questions!