Passivhaus Under Floor Heating & Water Supply

[Carpe Diem]

12 minutes ago, Conor said:

 

Which is why you run systems like this as a single zone (or zone per floor) rather than individual room stats. You probably don't want to hear this, but might be best ditching all the room stats and luxone stuff, and running it simpler. We've three floors, separated into two zones, runs on a manual timer (with one stat set to 21c, only in mild weather does it hit this) for 18hours a day on weather comp. I never need to think about it and I never notice when it's running or not.

Pros and cons though.... we dont have to worry about the temperature in any rooms and have no hot or cold spots. 
In another house we have it setup with one zone and its not great if doors are closed etc as we basically have to set the thermostat to 23C in the hall, and know that then means the bedrooms off it are near 21c.  When its a sunny day, the room at the back that gets all the sun over heats, because the hall is in the shade so it is not externally heated.

At least with sensor in each room, we have all the rooms perfectly balanced to the same temp.

[MPH243]

Yes I have the lan C module which was part of the package. It is very good but I did just see how much it is. 

 

Just out off interest can you check the usage on the units so we know there usage it is in menu, status and energy also the l/s flow rate.

 

I think your energy use is because the ashp is short cycling with the smaller circuits,  I have gone to 1 thermostat as 1 room would call for heat first but did not have enough volume in the system so kept cutting in and out. I only realised because I was outside doing something next to it and it kept cutting in and out. 

 

It was using more electric but I can't remember how much. I also have a 8.5kw ecodan. 

 

 

[Conor]

38 minutes ago, Carpe Diem said:

Pros and cons though.... we dont have to worry about the temperature in any rooms and have no hot or cold spots. 
In another house we have it setup with one zone and its not great if doors are closed etc as we basically have to set the thermostat to 23C in the hall, and know that then means the bedrooms off it are near 21c.  When its a sunny day, the room at the back that gets all the sun over heats, because the hall is in the shade so it is not externally heated.

At least with sensor in each room, we have all the rooms perfectly balanced to the same temp.

Thing is, once you have flow rates set, you won't have any cold or warm spots. That's the whole advantage of loving in a PH spec house. Either way, I wouldn't make any dramatic changes yet as I do think this high consumption is mostly drying out. Tho that one zone that calls for heat all the time when others don't might be worth tweaking down a bit so it doesn't call so much.

[Alan Ambrose]

OK you started my morning off well...

 

>>> That's the whole advantage of loving in a PH spec house.

 

Yeah, but you don't get to roll around on the sheepskin in front of the big log fire, do you?

[Carpe Diem]

On 07/02/2024 at 19:58, Conor said:

 

Which is why you run systems like this as a single zone (or zone per floor) rather than individual room stats. You probably don't want to hear this, but might be best ditching all the room stats and luxone stuff, and running it simpler. We've three floors, separated into two zones, runs on a manual timer (with one stat set to 21c, only in mild weather does it hit this) for 18hours a day on weather comp. I never need to think about it and I never notice when it's running or not.

Pros and cons though.... we dont have to worry about the temperature in any rooms and have no hot or cold spots. 
In another house we have it setup with one zone and its not great if doors are closed etc as we basically have to set the thermostat to 23C in the hall, and know that then means the bedrooms off it are near 21c.  When its a sunny day, the room at the back that gets all the sun over heats, because the hall is in the shade so it is not externally heated.

At least with sensor in each room, we have all the rooms perfectly balanced to the same temp.

 

 

[Carpe Diem]

On 07/02/2024 at 20:41, MPH243 said:

Yes I have the lan C module which was part of the package. It is very good but I did just see how much it is. 

 

Just out off interest can you check the usage on the units so we know there usage it is in menu, status and energy also the l/s flow rate.

 

I think your energy use is because the ashp is short cycling with the smaller circuits,  I have gone to 1 thermostat as 1 room would call for heat first but did not have enough volume in the system so kept cutting in and out. I only realised because I was outside doing something next to it and it kept cutting in and out. 

 

It was using more electric but I can't remember how much. I also have a 8.5kw ecodan. 

 

 

I have 2 x Q350's.  Currently, they both have 43w being used.
Year to date 36kWh.

The usage is pretty low compared to what the ASHP is using.

[MPH243]

That's good at least you know it's not using 130+w each that was mentioned before. 

 

It maybe be that like @Conor said and twerk that zone down a bit so it is not coming on so much. 

[Carpe Diem]

I have tweaked it down a bit, and what we can do is write a command so that if it is only one room at 5% it doesnt call.
We could delay it so that it has to be 2 or 3 rooms calling, or a greater difference.

[Kelvin]

Configure it so it’s one big zone on the ground floor operating in weather compensation mode for a while and compare the consumption to now and the room comfort. We have a fairly even temperature throughout the downstairs rooms. That said, we don’t have any doors fitted yet nor is the MVHR system on or any other appliances bar a few lights. We have planned for a Loxone system but it won’t be controlling the heating, DHW, or MVHR as I don’t see the benefit. 

[jack]

On 07/02/2024 at 11:34, Carpe Diem said:

good to see another Loxone user.

 

There are quite a few of us. Use the search function to find out more if of interest.

[Carpe Diem]

On 10/02/2024 at 16:34, Kelvin said:

Configure it so it’s one big zone on the ground floor operating in weather compensation mode for a while and compare the consumption to now and the room comfort. We have a fairly even temperature throughout the downstairs rooms. That said, we don’t have any doors fitted yet nor is the MVHR system on or any other appliances bar a few lights. We have planned for a Loxone system but it won’t be controlling the heating, DHW, or MVHR as I don’t see the benefit. 

Loxone is pretty good for the lighting and heating from my short experience.  The media side of things I have not been impressed with, but my biggest mistake is the HDAnywhere setup, just seems pointless and cheaper to buy Apple TV's in everyroom.

The main challenge we have is getting others used to Loxone, e.g. when guest stay over.  Talking about night mode and tripple tapping, compared to say a C4/Lutron with a nice labels switch on the wall...... its confusing.

[Kelvin]

Yes the touch switches aren’t the most intuitive. Hence why you want it mostly being activated by presence sensors with an obvious lights off in the bedroom at night. I’m surprised they don’t do a similarly labelled switch design to Lutron other than the very expensive flex. You can use retractive switches of course instead for areas your guests are more likely to be using the most. 
 

I don’t really see the benefit for heating however. If you have windows and blinds connected as well then I can see the benefit as you have a lot more control of the whole performance of the house but heating alone just seems to add another layer of complication. 

[jack]

39 minutes ago, Kelvin said:

I don’t really see the benefit for heating however.

 

I use it in place of a thermostat. It allows me to do things like enabling limited overheating during the cheap Octopus window, forcing heating when upstairs gets too cold. It does add complication, and arguably we could just accept the limitations of a fixed thermostat, but it seems a shame to have the capability and not use it.

[IanR]

47 minutes ago, Kelvin said:

I don’t really see the benefit for heating however.

 

As you mention it's about whole house control. So, for me, it's to co-ordinate Heating, Cooling or just recirc (for moving energy from solar gain areas to North East rooms) across ASHP, UFH, MVHR (incl. wet duct heater/cooler), external blinds and roof vents. Loxone also controls the hot water return circuit based on presence sensing.

 

1 hour ago, Carpe Diem said:

The main challenge we have is getting others used to Loxone, e.g. when guest stay over.  Talking about night mode and tripple tapping, compared to say a C4/Lutron with a nice labels switch on the wall...... its confusing.

 

Triple tapping is just an option on the Touch switches, if you want to emulate C4/Lutron then have a dedicated retractive switch, or bank of switches and have them etched/printed with the functions you want, but this wouldn't be my choice, it's better to automate where possible so that physical inputs are not required.

[JohnMo]

1 hour ago, IanR said:

Triple tapping is just an option on the Touch switches

And what advantages does it offer over a £2 light switch, except to confuse your guests. Aren't you just trying to reinvent the wheel, with an expensive price tag and bunch of functions you have get the instructions out every time you think about using them?

 

1 hour ago, jack said:

allows me to do things like enabling limited overheating during the cheap Octopus window, forcing heating when upstairs gets too cold.

Not sure you list anything a decent thermostat doesn't do.

[IanR]

21 minutes ago, JohnMo said:

And what advantages does it offer over a £2 light switch, 

 

Very few decisions in life only consider cost. 

[JohnMo]

1 minute ago, IanR said:

 

Very few decisions in life only consider cost. 

Other than cost, what advantages other than to confuse guests, do the switches bring to the party. The lights go on or off, you still seem to have to touch the switch.

[IanR]

3 minutes ago, JohnMo said:

Other than cost, what advantages other than to confuse guests, do the switches bring to the party. The lights go on or off, you still seem to have to touch the switch.

 

I've no experience of confusing guests with my own set up. The switches are seldom manually used for lighting, other than to occasionally change the scene from the automated one, but the switches do provide the ambient temp and humidity data to inform automation, as well as manually adjusting blinds, roof vents, manually boosting MVHR, setting the house alarm, setting house to night mode. They could also adjust audio volume, track forward/back etc. but I don't configure for this option. A huge benefit is being able to reconfigure any of the functions on to any switch positions.

[JohnMo]

On 06/02/2024 at 16:55, Carpe Diem said:

 

My understanding was that the underfloor draws the water from the tank

Hi do I you have a photo of the setup. If it is operating that way you will be getting a rubbish CoP, just because are alway heating the cylinder to around 50.

 

You may be better routing the UFH direct to the floor manifolds

[Kelvin]

34 minutes ago, JohnMo said:

Other than cost, what advantages other than to confuse guests, do the switches bring to the party. The lights go on or off, you still seem to have to touch the switch.

It can be easily configured to not confuse guests plus the switches can be programmed for things other than lights. Ideally the presence sensors ought to manage all that so there’s no need for guest confusing. That said,  I debated with myself about whether to install HA at all way back at the start as I know you did too as it’s not cheap. I did decide to install it in the end although mine won’t control the heating or MVHR other than the towel rails plus I didn’t automate any of the Velux windows. Arguably this whole home control is what it’s best at. 

[jack]

3 hours ago, JohnMo said:

Not sure you list anything a decent thermostat doesn't do.

 

All of the temperature sensors were already installed, and I had spare relays, so there was literally zero hardware cost to implement it in Loxone.

 

Feel free to query the need for home automation, but why would I add the cost of a separate thermostat that's guaranteed to be at most (but almost certainly not) as functional?

[Carpe Diem]

We have Loxone control the blinds, MVHR etc. Its fully automated throughout, so I was hoping the issue with the heating cost was largely due to ASHP not being configured correctly.

However, I now think that it may be a fundamental issue with the system specified.
When the UFH is called even a tiny amount it seems the ASHP kicks in 100% so its costing £100s of elect on ASHP to heat £1s of space.
I could change Loxone so that the heat isnt called until the temp is called in (for example) 2 rooms, or % open is 50%, but that could be false economy if it then takes x10 longer to heat the space.

 

Any suggestions?
How can I check if I have a UVC v OP (no idea what that actually means btw)???

 

Ref Loxone and confusing guests....Triple tap we have for night move, but its not common to tell someone to do this.
When its night and the switches arent illuminated (we dont have the glow light on  next to the beds) it can be confusing for a guest to press the switch and one of the corners and bring the radio on or open the blinds.  Its not the end of the world, but in IMHO... it looses some of the premium feel when people are confused.  
Everything else is on motion sensors, which people like.  Still prefer to an overly confusing C4 interface... but thats just my experience.

[Kelvin]

Add floor level sensors that bring a light on at its dimmest setting or a floor level light. 
 

 

[Carpe Diem]

10 hours ago, Kelvin said:

Add floor level sensors that bring a light on at its dimmest setting or a floor level light. 
 

 

Not sure how we could retro fit that, but it would be good to have a motion sensor at floor level that brings on the night light on the switch.

 

[Carpe Diem]

Ok, so the company that installed have visited today and found several things out and also made some changes.
He wasnt sure what UVC or OP stood for????
 

The UFH does not pull hot water from the HW tank.  There is a separate vessel next to it, small black unit about the the size of 8/10 litres, that circulates and heats the water for the UFH.

 

He found that the top up valve had been left open, so the tank was getting topped up with cold water.... wasting the hot water.  The pressure was at 2.4bar, which he said is high, but must be the pressure at which the water into the property is at, otherwise it would continue to increase.  Seems low pressure to me, but that is what he reckons it is correct.

He adjusted the compensation curve and set the tank temp to 50c, whilst changing the control unit so it now shows energy consumption.

At -3c external temp the curve is set at 40c.  At 10c it is set at 32c.

He reckons to try the HW running on a schedule of a few hours in the morning and a few in the evening, to see if that is enough for the usage.  Outside of those hours it will use the tank hot water, which will obviously cool throughout the day.

 

Any thoughts?