Heat Pumps - post here.

Mr Q · 11-02-2020 4:25pm

crip123 wrote: »

We just bought a 70's Bungalow , floor area is 130sqms , We're doing a full renovation with external insualtion and have gotten the builder to price up A2W vs an energy efficent boiler. The A2W heat pump is looking at 9.5k more (so 6k net after grant) . Anyone have any idea of the Payback? is it worth it?

An additional 9.5k seems very expensive over a boiler. Probably worth getting a few more prices on that section of the job.

I have one installed and would say it is well worth it. For heating and hot water it used 700 kWh of electricity for December and January just gone. I had a meter put in for this to track the usage.

From what MENACE2010 said about losing only 1 degree per day I assume he has a seperate DHW tank. Mine is built into the indoor unit and loses a huge amount of heat over 24 hours compared to what he has described. His set up sounds much better in this regard.

MENACE2010 · 11-02-2020 6:07pm

Mr Q wrote: »

An additional 9.5k seems very expensive over a boiler. Probably worth getting a few more prices on that section of the job.

I have one installed and would say it is well worth it. For heating and hot water it used 700 kWh of electricity for December and January just gone. I had a meter put in for this to track the usage.

From what MENACE2010 said about losing only 1 degree per day I assume he has a seperate DHW tank. Mine is built into the indoor unit and loses a huge amount of heat over 24 hours compared to what he has described. His set up sounds much better in this regard.

correct its a separate tank Dimplex ECO ECS300HP
ps. We have a closed water suppy, no longer 300 liter tank on the attic..

Mr Q · 11-02-2020 6:15pm

MENACE2010 wrote: »

correct its a separate tank Dimplex ECO ECS300HP
ps. We have a closed water suppy, no longer 300 liter tank on the attic..

That looks really well insulated, not surprised you're only losing only 1 degree per day.

If i had a choice I would go for that every time over the indoor unit I have with integrated tank. The insulation level is poor by modern standards but it is a packaging compromise to get everything into a 600mm by 600mm unit I assume.

John.G · 17-02-2020 2:46pm

That 1 degree per day may be a bit optimistic, I think that dimplex 300 litre unit claims 1.96kw/24 hr loss which equates (my calcs) to 5.62C/24hr loss or 0.23C/hr, still excellent.

ToxicPaddy · 23-02-2020 11:41pm

If anyone could help me here, I'd be very appreciative.

We moved into a new build late last year with a Dimplex A Class heat pump and so far it's not been a positive experience. The house is pretty much perfect except for the heating system issues and all this over a fairly cold miserable wet winter which hasn't helped.

In 4 months we have been in we had a few minor issues and one major issue which has seen the heating system stop working completely and the internal temp of the house drop to 14C, this weekend the second is occurring, again the heating system appears to have completely stopped and its currently at 17c inside but getting colder by the hour.

The first time, after a week of chasing the installers, they eventually arrived and really didn't seem too sure what they were doing. It's like it was the first time they actually saw a system like this and it didn't inspire confidence watching them work. They supposedly fixed the system but it hasn't been 100% since then. I've called and called but to no available, the only contact with them being a bill for something that should have been covered under warranty.

Then to add to it all, our last electricity bill was for €430, definitely not expected and not inspiring confidence in how efficient this system is meant to be.

Due to our experience with the original installers I really don't want to have to deal with them again as I know I'll spend weeks chasing them only to have the same result.

I heard so many positive things about these heating systems that I had high hopes but at this stage I've pretty much lost all faith in them.

If anyone can recommend a decent knowledgeable company around Dublin who know the Dimplex A Class systems, I'd happily pay them to come and try to sort this issue.

What I would like is for them to give the whole system a complete inspection, a full service and review it from top to bottom. Then to go through a few details with me to make a sure I'm not doing anything stupid.

I honestly believe that this system hasn't been configured correctly from the start and it could be a glimpse of what's to come, so I'd like a second opinion so to speak from someone who actually knows what they are doing.

I have found a few in the area but I would like personal recommendations rather than rolling the dice and ending up with the same experience again.

Thanks.

MENACE2010 · 24-02-2020 10:37am

Hi
Sorry to hear its not working out, I'm at the westcoast but so I cannot recommend a particulair installer for you, the company that installed /designed mine is ashgrove in dublin I would give them a call and they could give you a steer in the right direction.

contact Dimplex if you have not done so maybe they can assist as well .

Things to check ..
- Alarms on the control panel ?
- thermostats , set them as high as possible, check water flow at manifold (assuming you have underfloor heating), if you have rads check for air in the rads (try to bleed them)
- do you have hotwater , if so heatpump is functioning or using the imersion

Download the installers manual ( get a pot of tea / coffee and read through the installers and user manual end to end) , if you follow it correctly you can check it yourself ( if your comfortable enough with it)

Calahonda52 · 24-02-2020 6:58pm

Any other houses in the estate with the same issues?
find out who did the install and IIRC, the new Building controls system should enable you to find out who signed off on the design.
As advised earlier, get the serial number off the unit and contact dimplex, they have a reputational risk issue here to manage.
The unit may be a fake, there is growing evidence of "plumbers" buying kit directly from websites...... so if "plumbers" do it builders may also
The user manual should have been left in the house

Kash · 29-02-2020 11:52am

We have a 4 bedroom bungalow, built in the 70s. We are investigating installing a heat pump to replace/supplement our solid fuel stove. We had a SEAI registered assessor compete a technical assessment of the house, and he has given us a list of improvements - including installing UFH and replacing most of the windows and doors.

He gave me a ballpark estimate of the improvements coming to €50-60k which we simply cannot afford.

Is our dream of a warm house over?

Water John · 29-02-2020 12:01pm

Sealing and insulating the house are the two key essentials. The floor isn't the greatest loss of heat, but the most difficult to fix. To put in UFH means digging down 12-15 inches and putting in a sub floor and then 6 inches of insulation.
If you can avoid all that, the house won't be perfect but will be reasonably warm.
If you wanted to go HP then you could use aluminium rads.
Can the engineer give you a second BER calculation based on that? That won't take him 5 mins as he has the house entered on the software already.

Know an elderly relation who has a sort of prefab concrete house from the 1970s. He went with exsulation and it made a big improvement.

MENACE2010 · 29-02-2020 6:40pm

Kash wrote: »

We have a 4 bedroom bungalow, built in the 70s. We are investigating installing a heat pump to replace/supplement our solid fuel stove. We had a SEAI registered assessor compete a technical assessment of the house, and he has given us a list of improvements - including installing UFH and replacing most of the windows and doors.

He gave me a ballpark estimate of the improvements coming to €50-60k which we simply cannot afford.

Is our dream of a warm house over?

Hi, I don't think the dream is over. The assessor was a good start, the recommendations are what you would do in a perfect "money is no object" kinda situation.

The main aim is not to lose heat , once you can achieve that it does not really matter what the heating system is.

Window replacement - is a good start if they are old, cold, leaky and condensation is running off the glass on the inside. Shop around and ask for a quotations. Price varies significantly . If possible use triple glazing or double with a very good U value.

House insulation - equally a good start, pump cavity or use external insulation. Check the attic space where you are prone to lose significant amount of heat. Insulate the floor of the attic space if possible. Google , shop around ask questions ..

Ventilation - Air-tightness .. find the droughts and fix them, now if you have those lovely "holes in the wall " for ventilation , google for Heat recovery options for existing dwellings .. get advise what holes to can close up .

Stove replacement - if you have an open fire at the moment , get a stove and potentially a stove with an external fresh air feed from the outside. Most of the heat of the house leaves through the Chimney on older buildings.

HeatPump is nice but you need to ensure first that you don't or minimize the loss of heat otherwise it will get expensive very quickly. Get a new boiler is probably better in the long run ( condensing boiler) and equip rads with Thermostatic valves so they close and open on a set temperature.

Overall , split all this in smaller projects , check what grants you are entitled to use the grants for the big stuff and save for the smaller project bits (stove, rads )

antoinolachtnai · 29-02-2020 6:49pm

The above is excellent advice.

There is another way to look at it though. Your house needs a major refurb at some stage in the next twenty years. Rather than doing lots of items one by one you might be better doing the essential things now but deferring any major project for five or ten years and saving toward it in the interim. At that point make a large investment in a full retrofit and refurb of the house.

These are just ways of looking at it. The best option for you may lie somewhere in between the extremes.

Calahonda52 · 01-03-2020 3:27pm

https://www.nsai.ie/about/news/publication-of-sr-542014-code-of-practice
Good advice above,
some of the actions may delivery good airtightness so the work needs to be sequenced.
Starting point must be uncontrolled ventilation.
If doing windows then do them and EWI at same time , hanging the new windows on the outside, minimises thermal bridging.
What are the existing floors, if concrete then UFH will be a world of hurt
If timber and you intend to pour concrete then more hurt.

Its all doable but for the UFH etc you will need to move out: how practical is that?

ToxicPaddy · 02-03-2020 9:27pm

Thanks for the replies guys, the installers came back, said it was something they couldn't fix, gave me a list of error codes and referred me to Dimplex.

I've called Dimplex, gave them the info and informed me that it's a possible PCB failure but the system is under warranty for parts and labour so would have someone out on Monday (this was on Friday afternoon so reasonable to exoect). They would call me back then to confirm a time the engineer would call out st. No call by lunchtime so I called after lunch, they said they would call me back immediately, no call back so 10 days after initial report of fault, still no resolution in sight.

Getting a bit fed up with this a now and I've had to resort to buying some small fan heaters for the house as its too cold on the ground floor to spend any time there.

Water John · 02-03-2020 10:25pm

If my memory is correct, the local installer of Dimplex installs but activation, which cost something like €500 was done by Dimplex themselves. Stand to be corrected on this. But if that's the case, I would expect both phone support and attendance within 24 hours.

NonPlussedNW · 18-05-2020 1:50pm

I bought a recently completed house last October that has an Air to Water HP with UFH. I don’t think it is working as well as it should, but the installer insists all is well. I’m hoping someone with more experience of this type of setup can advise.

The house is rural, detached, 245sqm, well insulated (bead-filled cavity and dry-lined walls, triple glazing), A-rated but not passive. It seems to hold the heat well.

HP system is a Panasonic 12kw mono-block with a 70 litre heating buffer tank built in to the DHW tank. It is set for a heating water temperature of 37c. UFH has 10 zones with individual room stats.

First issue is that the system reports low COP values. Monthly averages for the first 4 months of this year were: 2.2, 1.6, 1.3, 1.4. So far this month it is 1.3.
I understand this can possibly arise from a mis-calibrated sensor causing a miscalculation of the COP, rather than an actual underlying problem, but is there any way to gauge for myself the actual efficiency level? I presume most installations manage to show reasonably accurate COP values, otherwise why have the display?

Second, I suspect the system isn’t pushing the heat round the system fast enough. I’ve been monitoring the temperatures in one 15sqm room, north facing so minimal solar gain. The heating system can run for 1.5 hours just to maintain this one room at set-point, raising the room temperature by half a degree. During this time the HP runs in cycles of approx 6-7mins on, 11mins off waiting for the buffer to cool. UFH systems respond slowly, but is this excessive?

The floor in this room is heated unevenly. Maximum floor tile surface temperature increase can be 3 degrees on one edge of the room, but barely one degree on the other. The return pipe at the manifold has almost no noticeable heat, even after running for over an hour. It seems like the heat is being circulated at too low a rate. With the valve wide open, the indicator shows 1 litre per minute flow on the loop, which I thought was a typical value but doesn’t seem sufficient. The circulation pump is a Grundfos in UFH mode on the lowest speed setting.

Initially there were multiple actuator valves stuck permanently open, which was corrected in February. This coincided with a significant drop in the reported COP. This would seem to confirm that the heat distribution is a bottleneck – the HP appeared to run more efficiently when the heat was always pumping to multiple rooms.

Third, the energy usage seems higher than expected. According to the electricity meter, total consumption has averaged about 690 units per month October-April. Internal finishing work continued through much of this time, so the house wasn’t full time occupied and had no other heavy energy consumers such as electric oven or dishwasher. HP would account for most of the electricity consumed, and this seems to tie in with the consumption reported by the HP itself.

With so many variables, I’ve found it is difficult to find any definitive information on what a reasonable consumption level should be. If the installer comes back, ups the pump speed and declares it fixed, how can I independently confirm that the system is actually running efficiently, especially when heating demand is much reduced in the warmer weather?

Are there any other potential causes that I should investigate?

John.G · 18-05-2020 2:24pm

You may be able to take a few readings with no hot water (demand) draw off, do you know what the 70 litre cutin/cutout temperatures are, if you do then it is a very easy to calc the energy required to bring it back up to temperature and if you can obtain elec meter readings for this period then the cop can be calculated, if you are taking the meter readings from the main "ESB" meter then ensure that there are no other large users on for this fairly brief period. Also, as I see you have a HP consumption meter, obviously note this as well.

MENACE2010 · 18-05-2020 3:24pm

NonPlussedNW wrote: »

I bought a recently completed house last October that has an Air to Water HP with UFH. I don’t think it is working as well as it should, but the installer insists all is well. I’m hoping someone with more experience of this type of setup can advise.

The house is rural, detached, 245sqm, well insulated (bead-filled cavity and dry-lined walls, triple glazing), A-rated but not passive. It seems to hold the heat well.

HP system is a Panasonic 12kw mono-block with a 70 litre heating buffer tank built in to the DHW tank. It is set for a heating water temperature of 37c. UFH has 10 zones with individual room stats.

First issue is that the system reports low COP values. Monthly averages for the first 4 months of this year were: 2.2, 1.6, 1.3, 1.4. So far this month it is 1.3.
I understand this can possibly arise from a mis-calibrated sensor causing a miscalculation of the COP, rather than an actual underlying problem, but is there any way to gauge for myself the actual efficiency level? I presume most installations manage to show reasonably accurate COP values, otherwise why have the display?

not all systems have a COP display ( have not seen it on mine) lower COP is A. based on the outside temp and potentially a misconfigured / badly placed sensor

Second, I suspect the system isn’t pushing the heat round the system fast enough. I’ve been monitoring the temperatures in one 15sqm room, north facing so minimal solar gain. The heating system can run for 1.5 hours just to maintain this one room at set-point, raising the room temperature by half a degree. During this time the HP runs in cycles of approx 6-7mins on, 11mins off waiting for the buffer to cool. UFH systems respond slowly, but is this excessive?

okay, check your manifold it could be valves are not opening correctly or not enough for the water to circulate, there could even be trapped air in the pipes, see if you can bleed the system

The floor in this room is heated unevenly. Maximum floor tile surface temperature increase can be 3 degrees on one edge of the room, but barely one degree on the other. The return pipe at the manifold has almost no noticeable heat, even after running for over an hour. It seems like the heat is being circulated at too low a rate. With the valve wide open, the indicator shows 1 litre per minute flow on the loop, which I thought was a typical value but doesn’t seem sufficient. The circulation pump is a Grundfos in UFH mode on the lowest speed setting.

uneven heating is loops under tiles not looped in a consistent manner not a whole lot you can do there

Initially there were multiple actuator valves stuck permanently open, which was corrected in February. This coincided with a significant drop in the reported COP. This would seem to confirm that the heat distribution is a bottleneck – the HP appeared to run more efficiently when the heat was always pumping to multiple rooms.

Check and Check again, it true the pumps work better with open flow, I stopped using my thermostats and use the Heatcurve setting on the HP to control the room temperature

Third, the energy usage seems higher than expected. According to the electricity meter, total consumption has averaged about 690 units per month October-April. Internal finishing work continued through much of this time, so the house wasn’t full time occupied and had no other heavy energy consumers such as electric oven or dishwasher. HP would account for most of the electricity consumed, and this seems to tie in with the consumption reported by the HP itself.

YUP welcome to the party, the power consumption can be high especially if its cold, ( less efficiency) the heatpump has to work harder with a lower outside temp = higher electricity costs

With so many variables, I’ve found it is difficult to find any definitive information on what a reasonable consumption level should be. If the installer comes back, ups the pump speed and declares it fixed, how can I independently confirm that the system is actually running efficiently, especially when heating demand is much reduced in the warmer weather?

Are there any other potential causes that I should investigate?

okay, there are a couple of points in your text that potentially could be causes for some extra attention

- check if there is no airlock in the UFH loops
- check if the attenuators are working correctly
- check if the sensors are working correct and display the correct temp
- Water pressure correct in the system (I presume so , but I had an installation error on my install.. the top up valve was left open and the system had overpressure all the time ..only when I closed that valve it was correct ) ?

So there is no "golden Rule" or comparison, I spend 170 euro a month with Airtricity on a spread payment contract, this is everything cooking /heating /working from home /hotwater. At the moment my heating is off and the HP only makes hotwater ( Elec.bill is now lower) but I have to pay for the differential

Water John · 18-05-2020 3:35pm

A while since involved in the trade but my memory is of 1.5l/min flow on each loop. The 15 sq m room should be one loop of about 100 metres (the max for a loop) at 150mm spacing. Water in might need to be at 40C to UFH.

If trades were working, doors in and out would be opening quite a bit.
If HW is at 70C that is high and would burn electricity to get there. (Misread the 70l tank there but check that the HW temp isn't too high.)
Are all the loops controlled by stats, one would really need to be an open circuit, so the water pump isn't hammering when all circuits close.

MENACE2010 · 18-05-2020 4:27pm

Water John wrote: »

A while since involved in the trade but my memory is of 1.5l/min flow on each loop. The 15 sq m room should be one loop of about 100 metres (the max for a loop) at 150mm spacing. Water in might need to be at 40C to UFH.

If trades were working, doors in and out would be opening quite a bit.
If HW is at 70C that is high and would burn electricity to get there. (Misread the 70l tank there but check that the HW temp isn't too high.)
Are all the loops controlled by stats, one would really need to be an open circuit, so the water pump isn't hammering en all circuits close.

I concur with the above, google for installation & planning manual <followed by the type and model of heatpump> and read that through so you have an understanding of why /how and what.

my tap water is 46C ... but the HP has an anti legionairs disease system once every couple days it fires the temperature up to 70C to kill whatever might lurk in the pipes and tank.

https://www.panasonicproclub.com/uploads/BE/catalogues/A2W_2018_DesignManual.pdf

Calahonda52 · 18-05-2020 5:09pm

Put a sub meter on the HP so as you know exactly what it is pulling.
Is your weather compensation control located properly and working properly
From what remember in a recent training course, 10 individual zones on a UFH set up is not good design

Water John · 18-05-2020 7:05pm

Zone the bedrooms, you have to, and any room with a second heat source, open plan the rest or with one master thermostat.

NonPlussedNW · 19-05-2020 12:56pm

Thanks for all the responses. Lots to look at.

John.G -Energy calculation. Going by the HP display, the system gets the buffer water up to temp and pauses once it gets to 38 or 39 degrees. It resumes once the water temperature falls back down to 33 degrees. Manifold out goes from 20 degrees room temp to 35 degrees when the pump starts. Manifold return temp doesn’t rise above initial 20 degrees at any point. Not sure that this is enough to go on to calculate a more reliable COP estimate, though.

MENACE2010 – Airlocks. The flow meter is showing 1 litre/minute on the loop. Could there be an airlock and still be flow? I, perhaps wrongly, associate them with blockage.
- Manifold actuators appear to be opening correctly, and showing flow as demanded by the relevant room stats.
- I’ll get the installer to check the sensor accuracy, when he returns.
- Water pressure valve shows around 1.5 Bar. The target indicator on the gauge has been turned to 2 Bar, but not sure if this was a deliberate setting by the installer or just how it came out of the box. The system seems to be holding at 1.5 bar and doesn’t appear to be losing pressure.
- I’ve read the installation & planning manual. It gave me a better understanding of the setup, but left me not much the wiser about how I judge how well this installation is performing.
- Uneven heating. I did wonder if poor pipe layout was the cause. Only the tiles over the first straight run of pipe show any significant heat increase, though, so it’s possibly the heat not penetrating far enough along the pipe run, rather than the layout.

Water John – DHW temp is set for 50 degrees. There’s supposed to be a sterilizing boost, as MENACE2010 mentioned, but I haven’t noticed it kick in.
- All heating loops are on stats, as far as I can see. HP and circulating pump don’t seem to run unless there is demand, though.

Calahonda52 – Sub meter does sound like the best way to get definitive usage.
- weather compensation is built in to the monoblock, but I’ll ask the installer to check.
- (and Water John & MENACE2010) Too many zones. I was thinking it might be more efficient to merge some of the zones, but want to make sure the system as installed is working properly before getting creative.

Calahonda52 · 19-05-2020 1:20pm

WC is critical for HP installs as the lower the demand water temp the higher the COP.

Water John · 19-05-2020 1:53pm

Return temp sounds low IWT. Maybe the loops are over 100m. There should be a loop for about every 15 sqm, max 14 loops on one manifold. I think with the size of your house, you possibly should have two manifolds. That may be why the flow rate at 1l/min is low. Can you tell us how many loops you have?
With everything on stats, any one stat will start the compressor, so you have more start/stops.

John.G · 19-05-2020 2:29pm

Re "easy" COP calculation, if you can tell me what the actual power consumption was for a complete cycle, ie from the time the compressor starts to stopping and measure the on time and the off times accurately then I can calculate a reasonably accurate COP for this period, obviously this only applies to the heating cycle so ensure that the hot water demand is satisfied before taking any readings....you are only talking ~ 0.25 to 0.5 kwh depending on the COP.

NonPlussedNW · 20-05-2020 3:14pm

John.G wrote: »

Re "easy" COP calculation, if you can tell me what the actual power consumption was for a complete cycle, ie from the time the compressor starts to stopping and measure the on time and the off times accurately then I can calculate a reasonably accurate COP for this period, obviously this only applies to the heating cycle so ensure that the hot water demand is satisfied before taking any readings....you are only talking ~ 0.25 to 0.5 kwh depending on the COP.

Thanks for the offer to calculate the COP.

Do you need the measurement of a single 6-7 minute On cycle, or of a full 1.5 hour run with multiple cycles that gets the room back up to temperature?

John.G · 20-05-2020 3:31pm

The cycle that I need is the both the 6/7 min ON time and the approx. 11 min off time, measure both times as accurately as possible and also the HP consumption during this time, it other words take the HP or/and ESB meter reading at the start of the ON period, compressor start, and take it again to when it stops. One complete cycle of ~ 17/18 minutes will suffice, for now.

NonPlussedNW · 26-05-2020 2:44pm

John.G wrote: »

The cycle that I need is the both the 6/7 min ON time and the approx. 11 min off time, measure both times as accurately as possible and also the HP consumption during this time, it other words take the HP or/and ESB meter reading at the start of the ON period, compressor start, and take it again to when it stops. One complete cycle of ~ 17/18 minutes will suffice, for now.

Turns out there's no decimal places on my electricity meter so I can't get an accurate enough reading. I had a go anyway and the meter didn't move, so under 1 kwh, as you predicted.

While I was doing this, it occurred that I'd still be relying on the unit's water temperature readings being accurate. If the HP unit's COP calculation is adrift it might be the sensors that are the cause. Might still be useful to compare the unit's total consumption reading with the meter to see if it seems close, so I might try that over a longer period.

Thanks again for the offer, though.

John.G · 26-05-2020 3:47pm

Actually, I would think that the temperature readings would be quite accurate, in order to monitor it over a period of time you would have to count the number of cycles and you are hardly going to stand in front of it for a week!, the HP COP calculation is probably just summating these cycles and also the power consumed to arrive at a COP so it should be reasonably accurate but the COP should be ~ at least 3 and maybe a fair bit more when its only heating the water to 35C which is ideal really.

Edit: Going on your original cycle times and assuming a compressor power of 3kw,I estimate that the COP was 2.2.

Dardania · 27-05-2020 9:23am

Kash wrote: »

We have a 4 bedroom bungalow, built in the 70s. We are investigating installing a heat pump to replace/supplement our solid fuel stove. We had a SEAI registered assessor compete a technical assessment of the house, and he has given us a list of improvements - including installing UFH and replacing most of the windows and doors.

He gave me a ballpark estimate of the improvements coming to €50-60k which we simply cannot afford.

Is our dream of a warm house over?

hi Kash - where was your technical advisor based, and would you recommend them?

Or anyone else here registered - I am in South Dublin, and am looking to go A2W using the SEAI grant in my reasonably well insulated 1950s ex-Corpo house

Calahonda52 · 27-05-2020 9:25am

Dardania wrote: »

hi Kash - where was your technical advisor based, and would you recommend them?

Or anyone else here registered - I am in South Dublin, and am looking to go A2W using the SEAI grant in my reasonably well insulated 1950s ex-Corpo house

Step one is airtightness must be up to scratch for a HP

Dardania · 27-05-2020 9:36am

Calahonda52 wrote: »

Step one is airtightness must be up to scratch for a HP

I reckon it's not bad albeit zero numbers to back up that assertion.

I have EWI, modern windows & doors, sealed attic hatch, a balloon up the chimney, and using an Aereco DCV system for ventilation.

How can I assess if it's up to scratch?

John.G · 27-05-2020 9:38am

John.G wrote: »

Actually, I would think that the temperature readings would be quite accurate, in order to monitor it over a period of time you would have to count the number of cycles and you are hardly going to stand in front of it for a week!, the HP COP calculation is probably just summating these cycles and also the power consumed to arrive at a COP so it should be reasonably accurate but the COP should be ~ at least 3 and maybe a fair bit more when its only heating the water to 35C which is ideal really.

Is your compressor fixed speed or variable speed, if fixed speed I may still be able to give you a idea of COP.

Calahonda52 · 27-05-2020 10:51am

Dardania wrote: »

I reckon it's not bad albeit zero numbers to back up that assertion.

I have EWI, modern windows & doors, sealed attic hatch, a balloon up the chimney, and using an Aereco DCV system for ventilation.

How can I assess if it's up to scratch?

A blower door test really.
Not the full passive house rig job, the more basic one

sarah88 · 11-06-2020 9:05pm

Hi I'm just wondering if anyone has experience of heat pumps with a cooling function for summer?

ShanE90 · 11-06-2020 9:57pm

Cooling with a heat pump that is setup for space heating (Underfloor /rads) will produce poor cooling output as cold air falls to the floor you would need to be close to the floor to keep cool.

Cooling the water in the system low enough to have any substantial cooling duty will cool the water below the dew point temperature of the surrounding air which will produce condensation...this rules out underfloor and radiators as they both will become wet.

One option would be to use fan coils which are specifically designed to collect condensation formed during cooling... this should be setup as an independent zone as all the pipework needs to be insulated with armaflex which has a vapour barrier, fan coils can also be used for heating.

Some manufacturers have fan assisted rads that can be used for cooling as they have condensate trays also.

Alternatively a split ac system which would be totally independent of the heatpump could be used it will work better and be more for for purpose

sarah88 · 11-06-2020 10:00pm

ShanE90 wrote: »

Cooling with a heat pump that is setup for space heating (Underfloor /rads) will produce poor cooling output as cold air falls to the floor you would need to be close to the floor to keep cool.

Cooling the water in the system low enough to have any substantial cooling duty will cool the water below the dew point temperature of the surrounding air which will produce condensation...this rules out underfloor and radiators as they both will become wet.

One option would be to use fan coils which are specifically designed to collect condensation formed during cooling... this should be setup as an independent zone as all the pipework needs to be insulated with armaflex which has a vapour barrier, fan coils can also be used for heating.

Some manufacturers have fan assisted rads that can be used for cooling as they have condensate trays also.

Alternatively a split ac system which would be totally independent of the heatpump could be used it will work better and be more for for purpose

Thanks a mill for the detailed reply, its really helpful.

Calahonda52 · 12-06-2020 8:31am

sarah88 wrote: »

Hi I'm just wondering if anyone has experience of heat pumps with a cooling function for summer?

as above, wont work with A2W, will work with A2A

An alternative, if you have MVHR is to put a cooling coil in it, however it's a bit complicated as to ensure you just don't drive up relative humidity, the air has to be chilled down to get at least some of the moisture to drop out.
http://www.dpcalc.org/

Mr Q · 12-06-2020 9:15pm

sarah88 wrote: »

Hi I'm just wondering if anyone has experience of heat pumps with a cooling function for summer?

I have my A2W setup to do this with the underfloor system. It won't cool the house in the same way A2A would but it is definitely noticeable on the warmer days.

ercork · 12-06-2020 11:50pm

sarah88 wrote: »

Hi I'm just wondering if anyone has experience of heat pumps with a cooling function for summer?

I got an A2A installed a few years ago for heating. I never took too much notice of the fact that it had a cooling mode. The summer before last was particularly warm and I switched it on for a while. It worked great - one night I even slept on my couch in the living room where the A2A is located because the bedroom was so warm!
I only ended up using it for a week or so so I don't really know what the running costs were.

Shefwedfan · 13-06-2020 8:55am

ercork wrote: »

I got an A2A installed a few years ago for heating. I never took too much notice of the fact that it had a cooling mode. The summer before last was particularly warm and I switched it on for a while. It worked great - one night I even slept on my couch in the living room where the A2A is located because the bedroom was so warm!
I only ended up using it for a week or so so I don't really know what the running costs were.

How is the A2A for heating compared to A2 W? Do people know?

Calahonda52 · 13-06-2020 8:09pm

Shefwedfan wrote: »

How is the A2A for heating compared to A2 W? Do people know?

The main issue with A2A is that you really cannot take advantage of night rate power to either heat up the slab or better, heat a thermal store.
A2A is much faster response so I have just specified one in a community facility to act a rapid response boost on top of an A2W rad system to heat the hall for the older generation

Count Mondego · 14-06-2020 10:44am

sarah88 wrote: »

Hi I'm just wondering if anyone has experience of heat pumps with a cooling function for summer?

I have a Geothermal HP that's integrated with the HRV system and cools the air. Also the Nilan Geo Heatpumps integrate both HP and HRV in one unit and can do the same. Can drop the air temperature up to 10 degrees

Dardania · 15-06-2020 10:14am

Calahonda52 wrote: »

A blower door test really.
Not the full passive house rig job, the more basic one

So, a very nice chap did the technical assessment for us, and our projected heat loss indicator will be 1.79W/K m2 - so meeting the threshold needed to avail of the SEAI grant.

Does anyone have any recommendations for heat pump suppliers & installers, active in the south dublin area? I want to go A2W, and ideally figure out some solution for DHW at the same time

Calahonda52 · 15-06-2020 12:42pm

Dardania wrote: »

So, a very nice chap did the technical assessment for us, and our projected heat loss indicator will be 1.79W/K m2 - so meeting the threshold needed to avail of the SEAI grant.

Does anyone have any recommendations for heat pump suppliers & installers, active in the south dublin area? I want to go A2W, and ideally figure out some solution for DHW at the same time

What stage is the design at?

Dardania · 15-06-2020 12:56pm

Calahonda52 wrote: »

What stage is the design at?

I'm living in the house - this would be retrofit. Call it "scoping" stage!

Calahonda52 · 15-06-2020 12:58pm

Dardania wrote: »

I'm living in the house - this would be retrofit. Call it "scoping" stage!

Dis you get an SR 50 calc done to size the rads, I have a guy in Tullamore who might do it but the design needs to be right first.

JonMac · 15-06-2020 1:44pm

I had a technical assessment done for a heat pump upgrade. The plumber asked what kW heat pump was needed and said the assessor should recommend it. The assessor wasn't obliging and said the plumber can work it out from the assessment.
I calculated the heat load from the numbers and got 6.4kW per hour on average year round. As the heating season is 6 months or so, does that mean I need about 13kW plus the hot water?
My gas boiler has been set at 13kW and that worked very well.

Calahonda52 · 15-06-2020 3:14pm

JonMac wrote: »

I had a technical assessment done for a heat pump upgrade. The plumber asked what kW heat pump was needed and said the assessor should recommend it. The assessor wasn't obliging and said the plumber can work it out from the assessment.
I calculated the heat load from the numbers and got 6.4kW per hour on average year round. As the heating season is 6 months or so, does that mean I need about 13kW plus the hot water?
My gas boiler has been set at 13kW and that worked very well.

What math did you do, give an example pls of one external wall?

Shefwedfan · 15-06-2020 3:31pm

JonMac wrote: »

I had a technical assessment done for a heat pump upgrade. The plumber asked what kW heat pump was needed and said the assessor should recommend it. The assessor wasn't obliging and said the plumber can work it out from the assessment.
I calculated the heat load from the numbers and got 6.4kW per hour on average year round. As the heating season is 6 months or so, does that mean I need about 13kW plus the hot water?
My gas boiler has been set at 13kW and that worked very well.

How do you do a technical assessment and then not recommend the heat pump? bit of a get out of jail card that one isnt it

Heat Pumps - post here.

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