Heat Pump & Night Rate Meter - a no brainer?

BarneyMc

I'll be using an A2W HP and will soon be getting my electric connection. It is a no brainer to get a night rate meter to avail of cheaper night time electricity?

If using this meter daytime rates work out at about 20 cent during the day and 10cent at night. The standing charge is about €60 more than the standard meter. Full details are covered here.

I've looked around the market and a lot of providers have plans with rates at around 15 cent (all day and night). So, is it still a no brainer to get on the night rate meter or may it be just as good to get on one of the better plans coming in at 15 cent per KWh?

stickybookmark

Barney, do you really think an air to water will run efficiently at night time when temperatures of the air outside are cold?
GSHP running on night rate is a no-brainer. But A2W I'm really not sure.

To make night rate worth the higher day rate price that comes with night rate, you need one major item in your house (e.g. heating) to be running on it plus a few smaller items (Always turn washing machine and dishwasher on at night for example)

BarneyMc

stickybookmark wrote: »

Barney, do you really think an air to water will run efficiently at night time when temperatures of the air outside are cold?
GSHP running on night rate is a no-brainer. But A2W I'm really not sure.

Of course an A2W running at night will not run efficiently but that's not what I'm asking.

stickybookmark wrote: »

To make night rate worth the higher day rate price that comes with night rate, you need one major item in your house (e.g. heating) to be running on it plus a few smaller items (Always turn washing machine and dishwasher on at night for example)

That would be my A2W heat pump. :rolleyes:

ht9zni1gs28crp

How long to make back that €60 in difference. Also what's your HW storage capacity like? What about when the UF calls for heat during the day?

stickybookmark

BarneyMc wrote: »

Of course an A2W running at night will not run efficiently but that's not what I'm asking.



That would be my A2W heat pump. :rolleyes:

So why would you get night rate electricity if it's not efficient to run your heat pump at night time?

BarneyMc

stickybookmark wrote: »

So why would you get night rate electricity if it's not efficient to run your heat pump at night time?

Cheaper electricity unit rate.

BarneyMc

miller_63 wrote: »

How long to make back that €60 in difference. Also what's your HW storage capacity like? What about when the UF calls for heat during the day?

If it calls during the day then so be it. Although possible, I don't think it's practical to totally block the HP running during daytime rate hours.

stickybookmark

BarneyMc wrote: »

Cheaper electricity unit rate.

I visited a house (to see their polished concrete floor as it happens) and the owner was trying this (night rate with A2W) said it wasn't working out for him.

I'll be curious to see how you get on but I would be sceptial based on the principle of operation of A2W - taking heat from the air and transferring it to your heating system. And you want to do that chiefly at night when the air is cold? It just doesn't make sense to me on paper.

ht9zni1gs28crp

BarneyMc wrote: »

If it calls during the day then so be it. Although possible, I don't think it's practical to totally block the HP running during daytime rate hours.

But you really need to do the maths to make back that €60 going forward. As someone who lives with an A2W HP and seeing the difference in rates its probably not worth the hassle!

Also do you have any PV Panels going in?

JB81

I have A2W and have it running only at night ( dual meter with night rate ), timed off during the day. Heats 300 Litre water tank at night too.
Temperature in the house is very nice all day and does begin to drop a small bit in the evening, but not enough to warrant me to boost heating. With the amount of insulation I have the heat is not escaping quick enough for me to need the heating on during the day ( most of the time ), however if temperature dropped to freezing outside for a continuous period ( ie: day and night like winter 2010/11 ) I would then boost it for a few hours in the afternoon.
Only other time pump is on during the day is if we need to top up hot water.
I definitely recommend night rate meter because, even though efficiency drops at night, I still maintain you save more than running heating during the day on standard rate without night meter.
Obviously if your insulation is not good, forget about A2W altogether!!

BarneyMc

stickybookmark wrote: »

I visited a house (to see their polished concrete floor as it happens) and the owner was trying this (night rate with A2W) said it wasn't working out for him.

I'll be curious to see how you get on but I would be sceptial based on the principle of operation of A2W - taking heat from the air and transferring it to your heating system. And you want to do that chiefly at night when the air is cold? It just doesn't make sense to me on paper.

At night the air is cooler but the electricity rate is cheaper. My questions is which wins out.

BarneyMc

miller_63 wrote: »

But you really need to do the maths to make back that €60 going forward. As someone who lives with an A2W HP and seeing the difference in rates its probably not worth the hassle!

Also do you have any PV Panels going in?

Yes, and that's why I posted the question - will a night rate meter save me money over a 12 month period? On the plus side it's cheaper electricity at night. On the down side it's more expensive daytime electricity, higher standing charges and less efficient HP functioning in the cooler air.

I would like to use PV in the future but no short term plans.

BarneyMc

JB81 wrote: »

I have A2W and have it running only at night ( dual meter with night rate ), timed off during the day. Heats 300 Litre water tank at night too.
Temperature in the house is very nice all day and does begin to drop a small bit in the evening, but not enough to warrant me to boost heating. With the amount of insulation I have the heat is not escaping quick enough for me to need the heating on during the day ( most of the time ), however if temperature dropped to freezing outside for a continuous period ( ie: day and night like winter 2010/11 ) I would then boost it for a few hours in the afternoon.
Only other time pump is on during the day is if we need to top up hot water.
I definitely recommend night rate meter because, even though efficiency drops at night, I still maintain you save more than running heating during the day on standard rate without night meter.
Obviously if your insulation is not good, forget about A2W altogether!!

Thanks for sharing a real experience. I have high levels of insulation and hope to have very good air tightness. Can I ask what floor you're using - sand/cement or liquid screed?

JB81

75mm standard fine mix concrete floors

JB81

BarneyMc wrote: »

Thanks for sharing a real experience. I have high levels of insulation and hope to have very good air tightness. Can I ask what floor you're using - sand/cement or liquid screed?

75mm standard fine mix concrete floors

BarneyMc

Would anyone else like to share their experience of how they use their HP and electric meter? I'm edging towards just using a standard meter and try to run the A2W HP during the daytime when temps are higher.

water-man

Hello,

Have a GSHP with UFH and HW - currently running night rate electricity. I'm only living in the house over 3 months so have only had one bill. It was Eur220 but it was an estimate.

My HP installer recommends running it during the day and not so much at night. I've discovered from my tinkering that I think he is right. If I run it at night the house is too warm for sleeping and then if it's off during the day it gets "cool" in the evening.

In saying this I plan to observe bills over the next few cycles before deciding if I should change meter as I run wash machine every night and dishwasher too.

WM

BarneyMc

water-man wrote: »

Hello,

Have a GSHP with UFH and HW - currently running night rate electricity. I'm only living in the house over 3 months so have only had one bill. It was Eur220 but it was an estimate.

My HP installer recommends running it during the day and not so much at night. I've discovered from my tinkering that I think he is right. If I run it at night the house is too warm for sleeping and then if it's off during the day it gets "cool" in the evening.

In saying this I plan to observe bills over the next few cycles before deciding if I should change meter as I run wash machine every night and dishwasher too.

WM

I'm a bit confused here. Are you currently on a night rate meter? I would have thought that for a GSHP it would be a no brainer to run it at night as the ground is not affected by night temperatures (well not near as much as air).

Also can I ask about your floors, liquid screed or sand/cement?

Metric Tensor

There are three competing issues here:

1. At what time your heat pump is most efficient.
2. At what time your electricity is cheapest.
3. How your floor screed (thermal store) behaves and when is best to heat it. This is often overlooked by people who are used to the rapid response (both in heating and cooling) of radiators. Most of us grew up with systems like this so it takes quite a change in mentality to adjust to a system with a slower (but more even) repsonse.*

*And of course the thickness and type of screed further complicate this matter.

BarneyMc

Metric Tensor wrote: »

There are three competing issues here:

1. At what time your heat pump is most efficient.
2. At what time your electricity is cheapest.
3. How your floor screed (thermal store) behaves and when is best to heat it. This is often overlooked by people who are used to the rapid response (both in heating and cooling) of radiators. Most of us grew up with systems like this so it takes quite a change in mentality to adjust to a system with a slower (but more even) repsonse.*

*And of course the thickness and type of screed further complicate this matter.

Perhaps, to some extent, the nature of the outside walls affect this also? External walls that are not slabbed will regulate the inside temp much better whereas slabbed walls will lend themselves better to the "rapid response".

Metric Tensor

Yup. Spot on.

Any thermally dense materials inside the insulation envelope will increase the size of your thermal store this includes "non-slabbed" masonry on the inner leaf of external walls and also blockwork partition walls inside.

A bigger thermal store is slower to heat up initially but retains and releases the heat over a longer period thus evening out your thermal response. This, in my opinion, is very helpful in houses designed to stay at close to a constant temperature throughout the year (or the heating season anyway) - which is exactly what UFH/heat pump systems aim to do.

Curious Geroge

Danfoss 13Kw A2W setup. Night rate meter. Mon-Fri its off 8:30 to 5:30 and on auto otherwise. Have it set at 22 Deg which is comfortable. I had by default though to install a day (14c) / night (7c) meter but I question if its right as it would seem to be better to use the air during the day. Interested to hear more.

Also, anyone know if I can just switch to day rate or does the meter need to be changed out ?

BarneyMc

Curious Geroge wrote: »

Danfoss 13Kw A2W setup. Night rate meter. Mon-Fri its off 8:30 to 5:30 and on auto otherwise. Have it set at 22 Deg which is comfortable. I had by default though to install a day (14c) / night (7c) meter but I question if its right as it would seem to be better to use the air during the day. Interested to hear more.

Also, anyone know if I can just switch to day rate or does the meter need to be changed out ?

I assume 8:30 to 5:30 is daytime? I stand corrected on my first post and you're right, there's more than just one night rate provider and you've the best rate. I will be asking how much it would take to switch out the night rate meter early next week so will let you know if someone else here doesn't know. Interesting to hear that even on these favourable rates, you're thinking about flipping back to a regular meter.

daizy17

stickybookmark wrote: »

I visited a house (to see their polished concrete floor as it happens)

I know its totally off topic but how was the polished concrete floor? We are very interested in this but havent seen many companies that do it. Have you found many and if so how were their prices.

Apologises thats its off topic.

stickybookmark

water-man wrote: »

Hello,

Have a GSHP with UFH and HW - currently running night rate electricity. I'm only living in the house over 3 months so have only had one bill. It was Eur220 but it was an estimate.

My HP installer recommends running it during the day and not so much at night. I've discovered from my tinkering that I think he is right. If I run it at night the house is too warm for sleeping and then if it's off during the day it gets "cool" in the evening.

In saying this I plan to observe bills over the next few cycles before deciding if I should change meter as I run wash machine every night and dishwasher too.

WM

The system needs to be designed and set up at the installation stage to run on night rate. I'm dealing with 2 heat pump suppliers. One supports night rate the other doesn't. The one that supports night rate has thermostats in the house (which is divided into zones).

The one that doesn't support night rate their system runs off an external temperature sensor that kicks the heat pump on/off based on the external temperature and the temperature of the return fluid in the heating pipes.

In both cases if your bedroom is too warm for sleeping even if you don't have a thermostat in your bedroom where you can put in a set point of 18 for night time, you can control the amount of UF heating fluid going to your bedrooms via the manifold for the UF heating. Assuming your bedroom is one zone or all bedrooms are one zone, you just decrease the flowrate to that zone at the manifold til you get it where you want it.

GSHP and night rate is a no-brainer

stickybookmark

daizy17 wrote: »

stickybookmark wrote: »

I visited a house (to see their polished concrete floor as it happens)

I know its totally off topic but how was the polished concrete floor? We are very interested in this but havent seen many companies that do it. Have you found many and if so how were their prices.

Apologises thats its off topic.

It looked amazing. We went to see that house as we were trying to choose between the limestone aggregate or the sandstone aggregate for our polished concrete floors. Sandstone has browns, reds, blues, greens in it, the limestone just has blues and greys.

We went for limestone in the end. You have to specify this to the concrete supplier before they come and pour your concrete obviously.

In terms of polishing it, the guy that's going to do it for us is charging 60 euro per square metre. Let me know if you want his details by PM.

Curious Geroge

stickybookmark wrote: »

The system needs to be designed and set up at the installation stage to run on night rate. I'm dealing with 2 heat pump suppliers. One supports night rate the other doesn't. The one that supports night rate has thermostats in the house (which is divided into zones).

I assume A2W systems since you mentioned the sensors. Can you PM the suppliers ?

stickybookmark

Curious Geroge wrote: »

I assume A2W systems since you mentioned the sensors. Can you PM the suppliers ?

Both A2W and GSHP actually. We wanted GSHP, were corralled into A2W by our builders, now the builder has gone bust (we're at wall plate complete stage no roof on yet) and we're finishing off the house by direct labour so it's back to GSHP!

I will be running it on night rate. I'll PM you now

stickybookmark

water-man wrote: »

In saying this I plan to observe bills over the next few cycles before deciding if I should change meter as I run wash machine every night and dishwasher too.

WM

Washing machine and dishwasher alone are not enough to justify the higher cost of day rate electricity that you are paying. You need to be running at least 30% of your total bill on night rate to justify it so you need one major item in your house (i.e. the heating) to be running on night rate. The washing machine and dishwasher just make up the numbers

BarneyMc

Curious Geroge wrote: »

Danfoss 13Kw A2W setup. Night rate meter. Mon-Fri its off 8:30 to 5:30 and on auto otherwise. Have it set at 22 Deg which is comfortable. I had by default though to install a day (14c) / night (7c) meter but I question if its right as it would seem to be better to use the air during the day. Interested to hear more.

Also, anyone know if I can just switch to day rate or does the meter need to be changed out ?

Just rang ESB Networks and it looks like I have to go with a dual tariff meter as this is what I requested in my initial application.

As soon as I'm connected (maybe next week) I plan on switching to another provider. Just off the phone with them and they said I can switch back to a standard meter for free but there will be a charge if I was to switch again.

So I'll go ahead with dual tariff for 12 months with provider x and then re-assess after that.

ht9zni1gs28crp

stickybookmark wrote: »

The system needs to be designed and set up at the installation stage to run on night rate. I'm dealing with 2 heat pump suppliers. One supports night rate the other doesn't. The one that supports night rate has thermostats in the house (which is divided into zones).

The one that doesn't support night rate their system runs off an external temperature sensor that kicks the heat pump on/off based on the external temperature and the temperature of the return fluid in the heating pipes.

In both cases if your bedroom is too warm for sleeping even if you don't have a thermostat in your bedroom where you can put in a set point of 18 for night time, you can control the amount of UF heating fluid going to your bedrooms via the manifold for the UF heating. Assuming your bedroom is one zone or all bedrooms are one zone, you just decrease the flowrate to that zone at the manifold til you get it where you want it.

GSHP and night rate is a no-brainer

This really doesn't make any sense at all, who is advising you on these two pumps and their system, yet more importantly the actual living with either of them?

Why on earth would you let your internal temp demands be governed by external temp after going to extremes to make your house airtight, insulated and cold bridge free as possible?

It sounds way more confusing than it needs be!

stickybookmark

miller_63 wrote: »

Why on earth would you let your internal temp demands be governed by external temp after going to extremes to make your house airtight, insulated and cold bridge free as possible?

That's how the A**g***e heat pump works! I spent 3 hours with their mechanical engineer having it explained to me in detail. It controls based on 2 temperatures:
- external temperature
- temperature of return heating fluid (e.g. UF heating pipes)

Metric Tensor

If there is no zoning within the house it will seriously affect your Part L compliance and what you describe above seems to be the case unless there are a number of return feeds each monitored for their temperature.

ht9zni1gs28crp

stickybookmark wrote: »

That's how the A**g***e heat pump works! I spent 3 hours with their mechanical engineer having it explained to me in detail. It controls based on 2 temperatures:
- external temperature
- temperature of return heating fluid (e.g. UF heating pipes)

So if the external heat temp drops below say 2 degrees overnight, your house maintains 18deg on its own internally without added input is the GSHP just going to start adding in heat regardless of comfort?

As the return UFH temp cant be used accurately in order for a decent response time?

Surely your UFH is zoned, each zone then calls for temp as and when it desires? These zones being in control of heat demand?

stickybookmark

miller_63 wrote: »

So if the external heat temp drops below say 2 degrees overnight, your house maintains 18deg on its own internally without added input is the GSHP just going to start adding in heat regardless of comfort?
?

A**g***e system doesn't have thermostats to control the zones it controls based on the external temperature and the temp of the return heating fluid.
During the commissioning phase you use the manifold to get the various zones of the house to what you want them to. The fact that your house is maintaining 18 will be reflected in the return temperature of the UF heating fluid which in turn controls the heat pump.

stickybookmark

Metric Tensor wrote: »

If there is no zoning within the house it will seriously affect your Part L compliance and what you describe above seems to be the case unless there are a number of return feeds each monitored for their temperature.

Well they are selling them like hot cakes so all those houses can't be failing part L compliance

Metric Tensor

There must be some form of zoning and independent thermostatic control of zoned areas then!!! Has to be!

There hasn't been a (proper) house built for many years in this country where there wasn't separate control of heating in different areas of the house.

stickybookmark

Metric Tensor wrote: »

There must be some form of zoning and independent thermostatic control of zoned areas then!!! Has to be!

There hasn't been a (proper) house built for many years in this country where there wasn't separate control of heating in different areas of the house.

The UF heating is divided into zones in the house, but they told me there won't be thermostat control of those zones inside the actual rooms themselves, only in the return loop of the UF heating fluid.

Metric Tensor

It sounds suspect to me!

In the usual modern system the heating is called to come on by the zone thermostat telling the system that said zone has dropped below the temperature set for that zone and then switches it off when/if the temperature gets to a certain level.

In an "old fashioned" system the heating appliance switches on when the user presses the "on button" (e.g. the timeclock) and then switches off when the return flow reaches a certain temperature. It then switches back on again as necessary when the return flow temperature drops. In this type of system the user controls the internal temperature by switching off the heating when the zone reaches a comfortable temperature - but you wouldn't be doing this with a heat pump.

I just can't see how monitoring the temperature of the return flow is sufficiently accurate or responsive to gauge the temperature of the zone.

I must point out that I would not count myself as an expert in heat pump systems so I could be proven wrong.

daizy17

stickybookmark wrote: »

daizy17 wrote: »

It looked amazing. We went to see that house as we were trying to choose between the limestone aggregate or the sandstone aggregate for our polished concrete floors. Sandstone has browns, reds, blues, greens in it, the limestone just has blues and greys.

We went for limestone in the end. You have to specify this to the concrete supplier before they come and pour your concrete obviously.

In terms of polishing it, the guy that's going to do it for us is charging 60 euro per square metre. Let me know if you want his details by PM.

Thanks for getting back to me. Yes if you had his name that would be great thanks. We were thinking of staining the concrete once its polished. I'm not sure if anyone does it here buts it looks amazing.

water-man

stickybookmark wrote: »

That's how the A**g***e heat pump works! I spent 3 hours with their mechanical engineer having it explained to me in detail. It controls based on 2 temperatures:
- external temperature
- temperature of return heating fluid (e.g. UF heating pipes)

The above sounds like the system I have.

1) user sets desired internal house temp on the HP user interface (I've recently discovered the user can have different temps at different times of the day e.g normal, boost, decrease)
2) the HP is monitoring the outside temp
3) the HP software has an algorithm (heat curve) that determines the required UFH return flow temp to maintain the desired house temp.

Any pump works at its most efficient when it is working to its designed load. Having room stats which in turn decide which zone to heat will reduce the efficiency of the pump as it is not working to its designed capacity.

WM

Metric Tensor

water-man wrote: »

3) the HP software has an algorithm (heat curve) that determines the required UFH return flow temp to maintain the desired house temp.

For it to be any use this heat curve would have to be bespoke to each house and compiled over a number of years.

Is there a learning algorithm in the software water-man. How many years have you had it?

BarneyMc

BarneyMc wrote: »

Just rang ESB Networks and it looks like I have to go with a dual tariff meter as this is what I requested in my initial application.

As soon as I'm connected (maybe next week) I plan on switching to another provider. Just off the phone with them and they said I can switch back to a standard meter for free but there will be a charge if I was to switch again.

So I'll go ahead with dual tariff for 12 months with provider x and then re-assess after that.

Just off the phone with another supplier and they charge €192 should I ever want to change the meter back to a standard 24h rate one. So not a massive commitment I suppose. ESB Networks are installing my dual tariff meter next week.

water-man

Metric Tensor wrote: »

For it to be any use this heat curve would have to be bespoke to each house and compiled over a number of years.

Is there a learning algorithm in the software water-man. How many years have you had it?

I'm only living in the house a few months so don't have a lot of data.

I do not believe it needs to be bespoke for each house as the user set the internal temp to what they are comfortable with and let the HP decide then what the UFH temps should be based on the outside temp. The user can also adjust the Temp difference where the HP kicks in.

For example, I've my house temp set for 20C on the HP, HP reads outside temp is 6C, HP tells me that to maintain internal temp (of 20C) the UFH return flow needs to be 22C. Assuming the outside temp does not change, the HP will not come on until the UFH is 19C (22C - 3C). The 3C value can be adjusted on the HP. If/When the outside temp changes the required UFH return flow temp also changes. Hope that makes sense.

As house is well insulated as the temp outside drops the HP can decide to come on and "top up" the house heat before I feel it inside.

I feel this is an great advantage of this system as when the temp drops outside the HP can begin to top up the heat before I've even noticed that the temp has changed.

Whereas if I had room stats inside my well insulated house, the house temp would be down low before the HP kicks in and thus I'd feel the house cool as the time taken to re-heat is not instant with a HP.

WM

KCross

Metric Tensor wrote: »

It sounds suspect to me!

In the usual modern system the heating is called to come on by the zone thermostat telling the system that said zone has dropped below the temperature set for that zone and then switches it off when/if the temperature gets to a certain level.

In an "old fashioned" system the heating appliance switches on when the user presses the "on button" (e.g. the timeclock) and then switches off when the return flow reaches a certain temperature. It then switches back on again as necessary when the return flow temperature drops. In this type of system the user controls the internal temperature by switching off the heating when the zone reaches a comfortable temperature - but you wouldn't be doing this with a heat pump.

I just can't see how monitoring the temperature of the return flow is sufficiently accurate or responsive to gauge the temperature of the zone.

I must point out that I would not count myself as an expert in heat pump systems so I could be proven wrong.

Its only suspect if it were a new technology being flogged. Its not new technology. Its out for decades and definitely works.

HP's and UFH work very differently to your standard zoned on/off type system where they "call" for heat and the burner comes on to heat that zone. UFH doesnt really work that way.

The HP is continuously pumping water around the floors and if you have a super insulated house then the heat coming off the floor will be very slow to release as it has nowhere to go and so the return temp will stay high and so the HP doesnt kick in. Conversly if the house is leaking heat the UFH will give off its energy and so the return temp to the HP will drop and eventually kick-in to return the floor to the correct temperature.

So, in a HP system the UFH pump is running 24/7 but the HP itself (i.e. compressor etc) is not.

miller_63 wrote: »

So if the external heat temp drops below say 2 degrees overnight, your house maintains 18deg on its own internally without added input is the GSHP just going to start adding in heat regardless of comfort?

As the return UFH temp cant be used accurately in order for a decent response time?

Surely your UFH is zoned, each zone then calls for temp as and when it desires? These zones being in control of heat demand?

The heat wont be added when external temp drops if the internal temp is maintained as explained above. Its a very dynamic system that maintains temp 24/7. Also keep in mind that the system is not going through huge wings in temperature. Its maintaining a constant temp throughout the day(unless you tell it otherwise).

The reason the HP is monitoring outside temp is because UFH is not like a rad. It doesnt give instant heat. If the outside temp drops you dont want to wait for the internal temp to drop before adding heat. You want it to add heat as soon as it senses the temp drop outside (since an ext temp drop is going to result in an increased heat loss internally) as it takes a few hours for the floor to send heat back into the room..... how sensitive the system is to external temp drop is dependent on your house fabric, air-tightness etc and crucially how you tweak the HP itself which has to be adjusted for each house.

This adjustment is the heat curve.... you can set a high heat curve which will drive more heat into the house for smaller temp drops outside.... you tweak the heat curve up/down until you find the setting that works for you and your house.

Metric Tensor wrote: »

There must be some form of zoning and independent thermostatic control of zoned areas then!!! Has to be!

There hasn't been a (proper) house built for many years in this country where there wasn't separate control of heating in different areas of the house.

Generally zones in an UFH system are not recommended or required. The idea is that the whole house is at the same temp but you can add zones if you wish which will reduce temp to that zone by simply shutting the flow of water to that room. Zones are not required though for a successful HP/UFH system.

Metric Tensor wrote: »

For it to be any use this heat curve would have to be bespoke to each house and compiled over a number of years.

Is there a learning algorithm in the software water-man. How many years have you had it?

The heat curve is variable and you adjust it on a per house basis. The house fabric and user requirements are what determine the best setting. Every house will be different.



On the night rate meter.... I'd recommend the night rate meter if you have a HP. You should not, generally, turn off the HP at night as that simply gives the HP alot more work to do during the day when you set it to come back on.... its better to maintain constant temp 24/7 than have it swinging up/down. If you really want a system that has temp swings just get standard gas/oil/rad type system.

If possible get your appliances to work on delayed timers to run at night and also configure the HP to heat all yout hot water needs during the night and you will easily justify night rate meter. My night rate use is 50% of my overall usage. My heating and hot water bill is around €700-€850 per year depending on weather, of course. I have a GSHP.

Water John

The whole house should not be one temp. Each bedroom and any room with a fireplace should be controlled each separately with thermostats. The general living area can be controlled by one or the master stat. This would normally be 21c. This could be the weather compensation stat mentioned.
You must have a sat in each bedroom. You set those at about 18c.
Each stat turns on and off an actuator which opens the valve for that room. It also turns on the circulating pump.

Control on the returning water is a very basic system and wasteful and uncomfortable, with bedrooms too warm.

If you wan to go night rate, which I believe runs from 11 pm to 8 am you possibly should have added storage and use an indirect loop.

I would personnaly go with storage as it means the HP is not kicking in and out often.

Metric Tensor

Thanks for the info lads. I don't disagree with anything there.

Personally I don't think I'd be too happy for a standard heat curve based in an average of all houses to decide my heating profile without taking into account the specifics of the dwelling, exposed areas, volume, ventilation rate, screed depth, etc. But maybe if there is sufficient scope to adjust the heat curve that can be overcome.

Three questions if that's OK:
1. Are the heat curves user adjustable?
2. Did you find the absence of zoning caused problems with your DEAP calc?
3. Is there any internal stat at all? I would have thought that having one in conjunction with the external stat would have greatly aided the system. But I suppose if the assumption is that it is always X degrees inside the manufacturers may be happy with that.

water-man

Water John wrote: »

The whole house should not be one temp. Each bedroom and any room with a fireplace should be controlled each separately with thermostats. The general living area can be controlled by one or the master stat. This would normally be 21c. This could be the weather compensation stat mentioned.
You must have a sat in each bedroom. You set those at about 18c.
Each stat turns on and off an actuator which opens the valve for that room. It also turns on the circulating pump.

For a Heat Pump system I would disagree with all of the above. Your Heat pump would run very inefficiently in a system like the above.

ted1

Metric Tensor wrote: »

For it to be any use this heat curve would have to be bespoke to each house and compiled over a number of years.

Is there a learning algorithm in the software water-man. How many years have you had it?

Most modern thermostats are learning ones, they look st the heat outside AV inside sand see how much heat is lost and how fast, then they see how long it takes to heat the house , that way if you say you want it to be 20 degrees at 7pm it knows restart heating it at 6:34 and so on

Metric Tensor

ted1 wrote: »

Most modern thermostats are learning ones, they look st the heat outside AV inside sand see how much heat is lost and how fast, then they see how long it takes to heat the house , that way if you say you want it to be 20 degrees at 7pm it knows restart heating it at 6:34 and so on

This specific system, from my understanding, is not learning and bases it's behaviour on pre-programmed profiles. If the system does have learning and some form of internal temperature measure then that is different.

Water John

Why would anyone want bedrooms at 21c? Lots of savings and better living conditions by having them at 18c. That could be 40% of the house. Also with individual stats, bedrooms not being used could be turned down further 16c or turned off.
A good water storage tank only loses one degree heat in 24 hours. It is better to use one both with HP and also wood pellet burners.

Otherwise revert to what we built 25 years ago. One system no zones. I thought we had moved a good bit from that?