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My Mitsubishi ASHP has used 1078kWh from 25 November to 31 December – Help please

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(@sarah)
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Hi,  I have a mitsubishi ASHP and have now had it for 7 years.  I am genuinely confused with some of the stats I'm seeing of people's running costs - and how much cheaper it is.  My own experience of underfloor heating in an approx 60 square metre new build with the ASHP is sky high energy bills, right from the start.  So much so, that I called the engineer back a few months after it had been commissioned as the bills were so high....and this was 7 years ago.  

I have 3 zones - bathroom (set to frost setting), bedroom (set to 14 degrees) and sitting area (set to 15 degrees) - any higher and I simply cannot afford to pay the bill.  I have contacted the installer to see if there were some settings I could change - possibly related to the SCOP (but I've no idea what to do with this!!) - I've looked at the manual as I'm not a stupid person, but that is not particularly easy to follow either.    

My energy usage (at standard rate of electricity 34.5 with Octopus) for 25 November to 31st December was 1078Mwh - yes MEGA !!  Again this is just for the floor space I have described.  For 1 January to 24 January 573Kwh - there will be another week to come - so approx 750Kwh.  I could understand if I'm heating up to a balmy 18 degrees but, believe me, the bathroom is COLD !!  Any thoughts/ideas would be gratefully received.


   
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(@derek-m)
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Hi Sarah,

Welcome to the forum and we will do our best to try to resolve your problems.

What type is your home? Do you have any heat loss calculations? Since it is a new build I assume it is fairly well insulated.

It would be useful if you could post some photo's of your system, both wide view and close ups of individual equipment.

 


   
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Abernyte
(@abernyte)
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Posted by: @sarah

for 25 November to 31st December was 1078Mwh - yes MEGA !

Eeek!  Are you sure you have your MW/h and KW/h correct?  that November to December monthly bill would have been £366,520 on the energy price cap for electricity.

A Mega Watt MW is a thousand Kilowatts. 1078 KW/h per month at the price cap comes out at £366.52 which is a realistic price.  It may not be the best you can achieve depending on how your system is setup, but realistic.


   
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(@sarah)
Estimable Member Member
410 kWhs
Joined: 1 year ago
Posts: 79
Topic starter  

@abernyte Well my solar PV shows for December as usage 1.04Mwh and I made a paltry 73 kWh from solar panels that month (overall though solar have been brilliant - gain in the summer, not so much in the winter)


   
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(@sarah)
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410 kWhs
Joined: 1 year ago
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Topic starter  

@derek-m OK - I'll look at getting some photos.  The new build is actually flat roof terrace at back of existing bungalow - basically extended the terrace out 4metres, the house is 13 metres wide and we have accommodation underneath - there are stairs down to the new part in the house too.  All very well insulated.


   
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Mars
 Mars
(@editor)
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I'm pretty certain that it should read 1078kWh or 1.078MWh. I don't even think it's possible for a heat pump to consume 350kWh per day. 35kWh per day, however, is far more realistic. But we'll wait for more data and images from @sarah.

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(@derek-m)
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Posted by: @sarah

@derek-m OK - I'll look at getting some photos.  The new build is actually flat roof terrace at back of existing bungalow - basically extended the terrace out 4metres, the house is 13 metres wide and we have accommodation underneath - there are stairs down to the new part in the house too.  All very well insulated.

Is the heat pump also providing heating for your bungalow?

What is the size of your heat pump?

 


   
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(@sarah)
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Joined: 1 year ago
Posts: 79
Topic starter  

@derek-m No the ASHP any is for the new build part of the house - approx 60 square metres - attached the model and a photo of the control panel (which I don't really touch)

IMG 5231
IMG 5232

 - having said that I did change the temperature you see - I'm not that sure what it refers to in my manual says target temperature - this was set to 21 degrees C and I changed it a couple of weeks ago to 15 and I also changed the DHW mode setting from normal to eco

This post was modified 1 year ago by Sarah

   
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(@derek-m)
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Posted by: @sarah

@derek-m No the ASHP any is for the new build part of the house - approx 60 square metres - attached the model and a photo of the control panel (which I don't really touch)

IMG 5231
IMG 5232

 - having said that I did change the temperature you see - I'm not that sure what it refers to in my manual says target temperature - this was set to 21 degrees C and I changed it a couple of weeks ago to 15 and I also changed the DHW mode setting from normal to eco

Hi Sarah,

Since you did not provide any heat loss calculations I must assume that you do not have any. Do you have an EPC showing energy consumption? Do you have a hot water cylinder that is heated by your heat pump?

So that I can create a mental picture of your system could you provide some photo's of the various items of equipment within your system, preferably with details of make and model.

Where is your heat pump located?

Do you have any large windows and are they double glazed?

 


   
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(@sarah)
Estimable Member Member
410 kWhs
Joined: 1 year ago
Posts: 79
Topic starter  

@derek-m Hi, Thanks for your reply.  No I've never done any heat loss calculations and I don't have an EPC showing energy consumption - to be honest when this system was installed I thought it would be the best thing since sliced bread - better for the environment, would heat up my space really lovely in the winter and use less energy.  In my experience - it is really complicated to understand the controls - if I change one setting how do I know that it's made any difference?  Changing the setting from 21 to 15 (as stated in previous reply) - I've no idea what this really is - this is on the control panel separate to the individual controls in the space itself.   Also,  having to do heat loss calculations/EPC showing energy consumption etc etc!!  I'm just happy when the temp outside is better and the ASHP doesn't need to come on and now dislike the really cold weather.  Ironically I wish we had installed a wood burner in this new space too and have even looked at ways that we could possibly get one in.  I phoned the installer last week (McGregor Heating) - they were really good and spoke to someone mentioning that usage was really really high and possibly the settings may need to be looked at - the woman was very nice and just said in a "knowing way" - that the settings were mostly likely correct.  I took this to mean, yes electricity bills will be high and when it's cold it has difficulty coping.  

IMG 5234
IMG 5233

 

 

The heat pump is located in a special (machine room) - all same level as the space itself.  I have windows, but they are all double glazed and new 7 years ago - the whole space is only 7 years old.  I've attached a couple of pictures of the hot water tank.


   
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(@derek-m)
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@sarah

Could you please show a photo of your heat pump, which should be located outside.


   
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(@sarah)
Estimable Member Member
410 kWhs
Joined: 1 year ago
Posts: 79
Topic starter  

@derek-m not great pictures I'm afraid - it looks out onto land which isn't mine.

IMG 5236
IMG 5235

   
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