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Air source heat pump performance

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(@george)
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230 kWhs
Joined: 3 years ago
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Posted by: @jet

Hi all

I fatefully had an ashp installed in January 2020 and after a full year I am counting the cost and licking wounds.

the unit is a 16 kw LG Therma V with hydro kit. In other words it is a high temp system, with two compressors running concurrently. The outside unit looks like a monobloc ,with twin fans whilst the inside system looks like a 4ft high metal box, but contains a variable speed compressor. It generates heats up to 80c, so the radiators in my house run hot (when they are on).

My house Is 220sqm (2200sqft) and after one year of operation the electricity bill has been shockingly high whilst the system used 11203Kwh in total for hot water and radiator heating. I believe that this is excessive as the property was not well heated, we have cold areas and at least 2 rooms are not used or heated at all as we have the radiators on lowest setting. The system exceeds the predicted usage and cost by almost 40%.

The installer stated it would cost 1140GBP to run per year Last year it cost more than 1600gbp to run and the house is not even properly warm and I have to use fan heaters to supplement heating in some rooms.

I have been onto HIES to get support to get the installer to look at the set up, but I do not believe the installer has any idea about my system, based on previous experience. They just tell me that it depends on how I use it !

Can anyone recommend a professional ASHP specialist who could come to survey my system and offer advice to set up properly? I am based in Bedfordshire.

Honestly, I fear that I have made the biggest financial mistake of my life. Since purchasing it for 16000GBP, It has cost me 1600GBP in electricity, 300GbP in extra heating costs when the system broke down during 27 days in December 2020, less than a year since installation. It is noisy and intrusive both externally and internally.

I have received just 2 RHI payments so far, as the installer failed to release my certificate and they have only just installed an mmsp which RHI are refusing to accept as it does not show the correct readings. 

I do not believe that the safe guards put in place by NICIEC or HIES to protect consumers are working effectively or quickly enough. 

Sorry for the rant, but you perhaps you can understand my frustration.

 

 

 

 

I'm sorry to hear about your issues.

 

I am also based in Bedfordshire so if you need any assistance send me a message. We have a 14kw system heating a 418M2 property so a property of your size with a 16kw systems shouldn't have any issues.

 

I can recommend http://www.aircool-systems.co.uk/ who service our system but I would first recommend understanding your system and potential issues with it before getting engineers out. Can you give a description of the central heating system in your property (radiators/circuits/controllers) so that we can better understand whats going on.

 

 

Mitsubishi Ecodan 14kw ASHP + 500l Cylinder


   
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(@derek-m)
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Hi JET,

Did you ever resolve your problems?


   
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 Jet
(@jet)
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23 kWhs
Joined: 3 years ago
Posts: 5
 

@derek-m

No unfortunately I am still having the same issues of inexplicably high running costs and noise.

The installer came last week to replace the non functioning monitoring system so that I would at least be in a position to record the consumption, but they did not address the issue of noise or the cost of running it 


   
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(@derek-m)
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Hi JET,

My first question would be 'how technical are you'? So that I can better decide how to guide you through some simple tests.

Where is your ASHP located? Does it have lots of space around it or are there walls or fences? A photo would be ideal.

Has anyone checked that refrigerant gas charge is correct?

Do you have an operators manual and does it show a Remote Controller on page 7?

If not, let me know and I will try to send you a copy, or you could send me a copy of your manual, which may be better.

My e-mail address is:- derek_marsh_aicss@yahoo.com


   
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 Jet
(@jet)
Active Member Member
23 kWhs
Joined: 3 years ago
Posts: 5
 
ThermaV

@george

Hi I would really appreciate some help and advice. I am not convinced that I have the right system installed. I am very concerned about the electricity usage, the noise from the system (pipes vibrating loudly sometimes) and the fact that I still need to supplement heating some rooms with a fan heater.

 

The system that I have is a LG Therm V 32 Split provides hot water and central heating to 12 radiators on the ground floor and 5 radiators and 2 towel rails on the upper floor. 4 radiators are maintained in low setting (1) the rest are set to 3-4 (on a scale of *,1,2,3,4 and 5).

Both the twin fan outdoor unit HU161HAU33 delivers fluid at LWT  55c and the indoor unit HN1610HNK3 takes the fluid temperature to LWT 80c. Both are located outside the main building. The indoor unit is in a waterproofed structure sitting on a flat roof.

The controller is set in the attic and there is a wireless thermostat in the hallway. The system is very primitive and I have no access to measure its performance - there are two electric meters in the attic that show the consumption of each of the two units.

One is higher than the other but last year the total usage was 11,203 kWh for the full 12 months of 2020 from installation date January 16th 2020 to February 18th 2021 (The system was not operational from Nov 27th to December 23rd 2020 inclusive due to a fault-during this month I had to use calor gas heaters and electric fan heaters), hence I include 12 months of full operation to mid Feb. 

So far in the 3 month period from 18th Feb 2021 to May 7th 2021 it had used 2667Kwh - I am not sure whether this is reasonable?

 

 


   
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(@derek-m)
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Hi Jet,

How well insulated is your home?

During the design stage did anyone state why you required a high temperature (80C) system?

The higher the output water temperature, the harder an ASHP system needs to work, and hence the more electrical energy it will consume.


   
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(@batalto)
Famed Member Member
3655 kWhs
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Posts: 1091
 

I'd suggest he goes through the house and does a heat loss and radiator calculation - room by room. Find out your heat loss and radiator power. I assume an 80 degree unit is really inefficient. We have a 260m2 house and the gas boiler is set to 45 and we are fine, not cold in any way. My guess is your radiators are crappy and your house isn't insulated very well - so you are just losing heat hand over fist. You'll need to spend as much (or more) in terms of gas heating for your house (depending on efficiency), the source of the heat is irrelevant. 

Also, what is your electricity tariff? Have you moved to the lowest cost supplier? 

 

Below is a sheet where you can go room by room to do a heat loss - just make your own copy. If you don't know, you cannot do anything. We need to measure, before we can have an impact.

https://docs.google.com/spreadsheets/d/1HAGXEC7WOhjsmXFf8Noh9CUvafc8E-DvoKn96zehmYc/edit?usp=sharing

12kW Midea ASHP - 8.4kw solar - 29kWh batteries
262m2 house in Hampshire
Current weather compensation: 47@-2 and 31@17
My current performance can be found - HERE
Heat pump calculator spreadsheet - HERE


   
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(@derek-m)
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Hi Jet,

Are you still having problems? If so, then please follow the link below and download the owners manual.

https://www.lg.com/uk/support/product/lg-HU161HA

Follow the instructions from page 16 and set your system for 'Auto' operation.

Then check and record your indoor air temperature, and the inlet and outlet water temperatures. Follow the instructions in the manual which explains how to obtain these readings.

If you have any problem obtaining the readings then please get back to me.

What type of heating system did you have before the ASHP was installed? Did the radiators get very hot and how much energy did it use?


   
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(@duncan-mac)
Trusted Member Contributor
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Posts: 33
 

Folks I have just had my Vaillant AroTherm 7kW ASHP install three weeks ago and I have been reading the horror stories of folks who are having a bad experience of ASHPs and I have great sympathy with them all. I'm frankly a bit worried. I did my homework and I discussed my options at length with my chosen installer but i am still apprehensive after such a major investment in Solar, Battery Storage and ASHP and really hope I don't regret the process.

I do think the whole renewable debate is a complexed issue and solutions are out there but we must be able to engage people who will honestly guide us through the process and know there business in depth. I feel that there are either  unscrupulous of untrained people out there advising and taking money from customers for systems which are either badly designed or simply not fit for purpose.

Perhaps what we all need is a flow diagram and guidance notes on how to proceed with this process and a list of does and don'ts, questions to ask installers, differences between New Build and retro fit, New and Older properties, etc. etc.

This might help to eliminate the myths and misunderstandings of renewables and ASHP in particular.

Its very very early days but my system is outperforming the calculated deliverables for the moment. I can only hope its continues.

 


   
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Mars
 Mars
(@editor)
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Topic starter  

@duncan-mac, in our case it took us two years to see that our system wasn't performing as it should, but through some tweaking and updates, I feel we finally have a system that now heats our house as it was intended to do.

There are a lot of cowboys out there, and I might name and shame one company who really were just unbelievable in what they tried to pull off. 

I wouldn't worry too much about your ASHP just yet. We've still had a lot of cold evenings, and if your system has been getting the job done, I think you'll be just fine. 

Buy Bodge Buster – Homeowner Air Source Heat Pump Installation Guide: https://amzn.to/3NVndlU
From Zero to Heat Pump Hero: https://amzn.to/4bWkPFb

Follow our sustainability journey at My Home Farm: https://myhomefarm.co.uk


   
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(@derek-m)
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Hi Mike-Patrick,

Did you ever find and rectify your leak?


   
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Mars
 Mars
(@editor)
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Topic starter  

@siko, George explains his consumption in his review, so you can roughly work out what the annual bills are like: https://renewableheatinghub.co.uk/mitsubishi-ecodan-14kw-ashp

Depending on your tariff, if it's around 15p/kWh, your £150 for winter months is a pretty good guesstimate - maybe closer to £200 when when it drops to -6C for a week like it did this February.

Buy Bodge Buster – Homeowner Air Source Heat Pump Installation Guide: https://amzn.to/3NVndlU
From Zero to Heat Pump Hero: https://amzn.to/4bWkPFb

Follow our sustainability journey at My Home Farm: https://myhomefarm.co.uk


   
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