I rent a 1-bedroom small bungalow from the council; all energy is electricity; there is no gas supply; and I need help to make sure my Ecodan is running properly and not set up wrong. I seem to be spending a lot of money, and some of the numbers may seem wrong or incorrect to me.
I will try to give as much information as possible with pictures of my setup. Radiators 1 bedroom. 2 in the living room. 1 kitchen, 1 bathroom, all with TRV valves open on 6
Direct HW set at 50 c
Heating mode is auto-adaptive with weather compensation set to 45 degrees flow at -10 and 30 degrees flow at 15 degrees.
1 wireless stat set at 18 degrees all the time in the living room
Hi. The room heating setup seems perfectly sensible at first glance but your COP ( % efficiency) looks very low. You calculate this by dividing the heat energy delivered by the electrical energy consumed. A COP of 3.5 should be the minimum aimed for. I would first look at your hot water heating cycle as this is likely to be the least efficient. How big is your cylinder? How often is it heated? I’ll have a look again in the morning to see if I’ve missed something.
House-2 bed partial stone bungalow, 5kW Samsung Gen 6 ASHP (Self install)
6.9 kWp of PV
5kWh DC coupled battery
Blog: https://thegreeningofrosecottage.weebly.com/
Heatpump Stats: http://heatpumpmonitor.org/system/view?id=60
Hi. The room heating setup seems perfectly sensible at first glance but your COP ( % efficiency) looks very low. You calculate this by dividing the heat energy delivered by the electrical energy consumed. A COP of 3.5 should be the minimum aimed for. I would first look at your hot water heating cycle as this is likely to be the least efficient. How big is your cylinder? How often is it heated? I’ll have a look again in the morning to see if I’ve missed something.
I'm not sure on the cylinder size. But my hot water is heated every morning from 6am-9am and thats it. I also wondered my smart meter is now showing 190/kwh is this daily usage or weekly or something it seem a big reading too me.
So doing a quick calculation of your COP gives Nov=2.3, Oct=1.9 and Sep=2.2. These figures are very low so we need to find out where all this electricity is going. Could you take a picture of your cylinder for me, it could be very large, also I should be able to tell if your hot water is heated via the heat pump or by an immersion coil. If the latter is true, that could account for very high usage.
Could you also get a picture of your loft space to check what insulation you have up there? If you heat is going straight through the ceiling, that could also be a factor.
190 kWh is a lot of electricity, even for a week, my monthly usage last bill was 222 kWh and I have a two bed bungalow, albeit with solar panels etc.
A 3 hour heating slot for a cylinder is quite long, my guess is that is where the problem is.
House-2 bed partial stone bungalow, 5kW Samsung Gen 6 ASHP (Self install)
6.9 kWp of PV
5kWh DC coupled battery
Blog: https://thegreeningofrosecottage.weebly.com/
Heatpump Stats: http://heatpumpmonitor.org/system/view?id=60
I rent a 1-bedroom small bungalow from the council; all energy is electricity; there is no gas supply; and I need help to make sure my Ecodan is running properly and not set up wrong. I seem to be spending a lot of money, and some of the numbers may seem wrong or incorrect to me.
I will try to give as much information as possible with pictures of my setup. Radiators 1 bedroom. 2 in the living room. 1 kitchen, 1 bathroom, all with TRV valves open on 6
Direct HW set at 50 c
Heating mode is auto-adaptive with weather compensation set to 45 degrees flow at -10 and 30 degrees flow at 15 degrees.
1 wireless stat set at 18 degrees all the time in the living room
The energy supplier is British Gas.
Product type Pay As You Go
Product end date: not applicable
Standard (PP) unit rate: 26.130 p/kWh
Standing charge: 59.580p per day.
If you press the tick button again you'll get a breakdown of heating and HW so you can work out a COP for each.
So doing a quick calculation of your COP gives Nov=2.3, Oct=1.9 and Sep=2.2. These figures are very low so we need to find out where all this electricity is going. Could you take a picture of your cylinder for me, it could be very large, also I should be able to tell if your hot water is heated via the heat pump or by an immersion coil. If the latter is true, that could account for very high usage.
Could you also get a picture of your loft space to check what insulation you have up there? If you heat is going straight through the ceiling, that could also be a factor.
190 kWh is a lot of electricity, even for a week, my monthly usage last bill was 222 kWh and I have a two bed bungalow, albeit with solar panels etc.
A 3 hour heating slot for a cylinder is quite long, my guess is that is where the problem is.
Odear thats not very good then. I don't know much about this kind of thing so appreciate the help.
HUG were the installers and they were not very good at explaining things. I can't get into my loft at the moment but will provide info from my energy certificate from gov.uk . All the radiators were brand new and are very hot too touch and heat up quick. I think the pipes come in from the ceiling. Even during summer with holiday mode activated it seemed to using about £5 a day now its about £9 daily. I have added some more pictures to help. The water was originally on 24/7 in the schedule timer but I changed the graph so to only heat up from 3 hours in the morning as of last week. Just to see if tinkering around would make it better or worse possibly.
Current score 54E Potential 116A
Property type end-terrace bungalow Total floor area 39 square metres
Feature Description Rating Wall Cavity wall, filled cavity Good Wall Cavity wall, as built, insulated (assumed) Good Roof Pitched, 200 mm loft insulation Good Roof Flat, insulated Average Window Fully double glazed Average Main heating Air source heat pump, radiators, electric Good Main heating control Time and temperature zone control Very good Hot water From main system Very poor Lighting Low energy lighting in 80% of fixed outlets Very good Floor Suspended, no insulation (assumed) N/A Floor Solid, no insulation (assumed) N/A Secondary heating Room heaters, dual fuel (mineral and wood) N/A
Primary energy use
The primary energy use for this property per year is 393 kilowatt hours per square metre (kWh/m2).
Heating this property
Estimated energy needed in this property is:
8,070 kWh per year for heating 2,157 kWh per year for hot water
Your radiators are very hot to touch? Are you sure your weather compensation is set correctly? Our is about 30 at 15C to 45 at +2, and the radiators get warm, not hot. Do you know how often the heat pump comes on and off?
@disabledman From your image, your water tank size looks fine for a single bed house. I cant tell whether or not it is heated by the heat pump, but your EPC states you water heating is "very poor" so that would suggest to me that it might be heated by an immersion coil.
If it is though I still wouldnt expect you to use more than 2-4 kWh per day heating domestic hot water. If you dont have a lot of baths and/or you find that you have to cool down your hot water with cold water, I would definitely consider lowering the temperature to which you heat your water tank. You could do this by reducing the time you heat it for or turning down the immersion coils thermostat.
So if it isnt your hot water that is the main issue then it must be your heating. From your initial post, your radiator temperature should be about 35-40 C in the current weather, so not hot as @guthrie suggests. It would be very useful if you could get the split COP for heating and hot water from the Ecodan controller as @kev-m describes. If you heat pump is heating your radiators to 50C, that could account for the very large electricity bills. then we just have to work out why its doing that 😉
House-2 bed partial stone bungalow, 5kW Samsung Gen 6 ASHP (Self install)
6.9 kWp of PV
5kWh DC coupled battery
Blog: https://thegreeningofrosecottage.weebly.com/
Heatpump Stats: http://heatpumpmonitor.org/system/view?id=60
Let's clarify a couple of things. You have an Ecodan tank, so that will use a heat plate exchanger to transfer the heat to the cylinder. Getting the heat pump to supply water at 55°, which it will do get the tank to 50°, is always going to take the pump into its least efficient area of heat production. As long as a single cylinderful is enough to last you the day I would suggest running the HW later in the afternoon possibly - 6am is often the coldest part of the day and so makes it the process even less efficient. The length of the period you set doesn't really matter as once the tank is heated the process ends.
Weather compensation adjusts the temperature of the flow to the curve that has been set, so you would expect to see a close correlation between them. I would expect the curve was set by the installer and to figures used in modelling heat loss with an internal temp of 20°, which is higher than your desired setting of 18°. The 'ideal' curve matches the heat loss of the house, but this is trickier to work out in the real world and is only useful if your heating is then on all the time. If you have it running on on/off blocks then the curve needs to be run at a higher level in order to put in enough heat in compensate for the time it is off.
You are running Auto adaptation mode and looking at the image of the main screen on the controller I would judge that you either have a big temperature setback programmed in, or complete on/off blocks, perhaps even gas boiler style short on periods in the morning and evening. Auto adaptation is really a comfort setting, intended to maintain a desired internal temperature. One consequence is that if the heating period starts and there is a big difference between actual and desired temps the system will run hard in order to raise the internal temp up as quickly as it can, pushing flow temps up into the 50s. I suspect this is why it is costing you more in electricity in to get the heat out and you end up with a low COP. It is counter-intuitive to let your heating be 'on' all the time but AA really works best if it is spending a large chunk of the day on and not working hard to generate the heat required (which it will do in short chunks). For comparison my heating is on 24/7 but with a setback of 2° for 6 hrs at night, this effectively turns the heating off for 6 hours unless it is a much colder night, in which case it is not trying to make up a large deficit. I get a better COP overall than using WC.
If you want to stick with shorter defined periods of heating on I think WC might be a better choice to try, you will have more direct control over the flow temps when it is working. But it might take some experimentation to find what curve settings work best for your house and heating periods.
Holiday mode – I only tried this once when I was away and was slightly shocked to find that my heating actually came on when I expected it to be off. I haven't found the settings to change it as yet, but by default they seem to run your heating even if the weather is mild as opposed to hot. If you want your heating off completely in the summer it is best to set a summer schedule in the controller.
Mitsubishi EcoDan 8.5 kW ASHP - radiators on a single loop 210l Mitsubishi solar tank Solar thermal 3.94kW of PV
Let's clarify a couple of things. You have an Ecodan tank, so that will use a heat plate exchanger to transfer the heat to the cylinder. Getting the heat pump to supply water at 55°, which it will do get the tank to 50°, is always going to take the pump into its least efficient area of heat production. As long as a single cylinderful is enough to last you the day I would suggest running the HW later in the afternoon possibly - 6am is often the coldest part of the day and so makes it the process even less efficient. The length of the period you set doesn't really matter as once the tank is heated the process ends.
Weather compensation adjusts the temperature of the flow to the curve that has been set, so you would expect to see a close correlation between them. I would expect the curve was set by the installer and to figures used in modelling heat loss with an internal temp of 20°, which is higher than your desired setting of 18°. The 'ideal' curve matches the heat loss of the house, but this is trickier to work out in the real world and is only useful if your heating is then on all the time. If you have it running on on/off blocks then the curve needs to be run at a higher level in order to put in enough heat in compensate for the time it is off.
You are running Auto adaptation mode and looking at the image of the main screen on the controller I would judge that you either have a big temperature setback programmed in, or complete on/off blocks, perhaps even gas boiler style short on periods in the morning and evening. Auto adaptation is really a comfort setting, intended to maintain a desired internal temperature. One consequence is that if the heating period starts and there is a big difference between actual and desired temps the system will run hard in order to raise the internal temp up as quickly as it can, pushing flow temps up into the 50s. I suspect this is why it is costing you more in electricity in to get the heat out and you end up with a low COP. It is counter-intuitive to let your heating be 'on' all the time but AA really works best if it is spending a large chunk of the day on and not working hard to generate the heat required (which it will do in short chunks). For comparison my heating is on 24/7 but with a setback of 2° for 6 hrs at night, this effectively turns the heating off for 6 hours unless it is a much colder night, in which case it is not trying to make up a large deficit. I get a better COP overall than using WC.
If you want to stick with shorter defined periods of heating on I think WC might be a better choice to try, you will have more direct control over the flow temps when it is working. But it might take some experimentation to find what curve settings work best for your house and heating periods.
Holiday mode – I only tried this once when I was away and was slightly shocked to find that my heating actually came on when I expected it to be off. I haven't found the settings to change it as yet, but by default they seem to run your heating even if the weather is mild as opposed to hot. If you want your heating off completely in the summer it is best to set a summer schedule in the controller.
Just a clarification, are you running a fixed flow temp instead of wc?
Just a clarification, are you running a fixed flow temp instead of wc?
@newhouse87 The pic of the main controller screen posted shows the system running in Target Room Temperature aka Auto Adaption mode.
@disabledman I also meant to add that it look like your tank and pipework is mounted in a cupboard(?) accessed from outside. If this is the case, the door needs to fit as snugly as possible to reduce drafts and be as insulating as possible to reduce heat losses from the tank and pipework. Really all pipework should be properly insulated, though it is a real pain with the design of this unit. Of particular note with the Ecodan tank are the two flow and return thermistors which are mounted in clips attached to the pipes just underneath the main FTC box. These definitely ought to be insulated, at the very least by having some rockwool type material packed round them. As the flow and return temps are key to the FTC making decisions about how hard to drive the heat pump if these thermistors are reporting temps below the actual water temps, which they may well be if the thermistor mount is also surrounded by colder air, then your unit may be working harder and so more expensively than it needs to.
Mitsubishi EcoDan 8.5 kW ASHP - radiators on a single loop 210l Mitsubishi solar tank Solar thermal 3.94kW of PV
