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[M0rtimer]

Hi,

I am a complete novice/idiot when it comes to home diy/build issues.

 

We had an ASHP installed 11 months ago and it has proven totally unsuitable for our property.  It struggles to mainatin temperature during cold spells, is on constantltly so that the electric usage is huge and only heats the water to 45C which is not enough for the 4 in the house when we want baths/showers in the evening.

 

Rather than this being a sysytem to improve our lives, we are having to change our lifestyles to fit with the machine.

 

Any thoughts?   I may put it all on the for sale page!!

 

Midea R32 with Tempest tank

Edited January 26 by M0rtimer

[nod]

Unfortunately like Solar panels before 

We are going to see lots of mis selling cases With the majority of companies claiming that by moving from gas to a HP will slash your bills In reality HPs arnt suitable for the majority of homes 

 

Making sure that your loft is well insulated and and around door and windows are as airtight as possible 

[SteamyTea]

There are a few things that can be checked and adjusted to improve performance.

 

First things first, what did your energy survey say about your heat loads?

 

[M0rtimer]

I willsee if I can find any information. 

[M0rtimer]

[ProDave]

So total energy demand 25,265kWh per year, which currently at about 28.5p per kWh is an astonishing £7200 per year.

 

What were you paying previously?  I bet it is nothing like that.  I would have ran a mile from that.  How much are you actually using per month?  And remember this will be in addition to your normal usage.

[M0rtimer]

8 minutes ago, ProDave said:

So total energy demand 25,265kWh per year, which currently at about 28.5p per kWh is an astonishing £7200 per year.

 

What were you paying previously?  I bet it is nothing like that.  I would have ran a mile from that.  How much are you actually using per month?  And remember this will be in addition to your normal usage.

The meter also covers a farm building with units so not all the house, but yes, the bill was indeed around £7,000 per annum.

The ASHP is just for the house itself.  

 

It is such a disater, I am tempted to remove and sell used?

[BadgerBadger]

1 hour ago, ProDave said:

So total energy demand 25,265kWh per year, which currently at about 28.5p per kWh is an astonishing £7200 per year.

 

What were you paying previously?  I bet it is nothing like that.  I would have ran a mile from that.  How much are you actually using per month?  And remember this will be in addition to your normal usage.

 

Haven't checked the sums on total heat loss, but if that's the total figure for losses then the ashp consumption should be ~one third of that if we roughly assume a COP of 3.

[Andehh]

What research did you do into ASHP and it's applicability to you?

 

How did you come across the need for one? Are you on mains gas?

 

DHW is an instant odd one, ours currently heats ours to 50degs, and can do nearly 55 degrees. Yours should be able to do the same.

 

Do you have UFH? Did you over size the radiators?

 

Your heat loss is pretty average for a newish buildin the last 10/20 years and isn't the worst I've seen, but it won't be cheaper to run then other sources of heating... I wouldn't expect it to be ruinous to run though.

 

How warm do you like the house?

 

Also, what's your actual usage of the ASHP? "powering external units" clouds the information you're providing.

Edited January 26 by Andehh

[M0rtimer]

I hope this helps if I answer each point - but I am dim on some of it!

 

What research did you do into ASHP and it's applicability to you? - I spoke to a couple of registered companies, one just 3 miles from me was highly recommended.

 

How did you come across the need for one? Are you on mains gas? - Oil boiler which was at the end and needed replacing and thought I would do might bit for the planet.  We have also fitted solar panels.

 

DHW is an instant odd one, ours currently heats ours to 50degs, and can do nearly 55 degrees. Yours should be able to do the same. - The company said best efficiency was betwen 40 and 45.  It will do higher but is then working harder.

 

Do you have UFH? Did you over size the radiators? - UFH on graoundfloor 30ft x 90ft and then radiator in 7 first floor rooms.  

 

Your heat loss is pretty average for a newish buildin the last 10/20 years and isn't the worst I've seen, but it won't be cheaper to run then other sources of heating... I wouldn't expect it to be ruinous to run though. - I agree our biggest issue is heat loss.  The ASHP then struggles to hold the temperature and heat the hot water.

 

How warm do you like the house? goundfloor 20C.  Small annex with elderly mother 22C and upper floor bedrooms 21C

 

Also, what's your actual usage of the ASHP? "powering external units" clouds the information you're providing. The electric usage from 10th january - 1st October was 6056kwh.

[Andehh]

I don't think 6000 for nearly a years usage is THAT bad? For an average newish home. Especially if you are also warming an annex etc.

 

ASHP running for very long periods can be unnerving but it's what they do, you need to run them long and low!

 

 

[BadgerBadger]

11 hours ago, M0rtimer said:

 

Also, what's your actual usage of the ASHP? "powering external units" clouds the information you're providing. The electric usage from 10th january - 1st October was 6056kwh.

 

So ashp electric usage of 6000 kWh (plus a bit more for Nov/Dec) seems broadly consistent with the heat loss prediction you posted above.  But you shouldn't be paying £7k for that much electricity surely?  What's the total usage on your bill? Is something else happening?

[Andehh]

And as said.... Something isn't adding up, 6000kwh used for ASHP, assume 7500kwh for total annual usage, at 26p/kwh is only £160 odd a month.

 

Probably a bit less with solar panel..... All seems remarkably normal??

 

Your problems are elsewhere, your ASHP is working perfectly fine! It's running for long times, at high efficiency, low temps, giving you a warm house for pretty reasonable heating costs.

 

Edit... Also, we changed our hot water temp to 50 degrees for winter usage and the impact on things hasn't been much, certainly not enough for me to feel the need to change it back!! Yes 45 is more efficient, but probably only to the tune of a couple quid a week.

Edited January 27 by Andehh

[M0rtimer]

Thank you all, this is comforting.   The ASHP is using the 6000kwh over the 10 months.  The rest is farm/business units which is why it reaches the £7200.

 

I think you are suggesting that I can turn up the water temperature on both the underfloor and the hot water system and monitor effect and usage. 

 

I think one issue has been if the hot water is low, then when you have a bath or shower little to no cold is dded and so with 4 in the house, there is not enough hot water for all getting ready for an evening out.   With the old boiler system at 65C, there was hot water that you then topped up with cold, so plenty in the tank for all.

 

As I said at the start, it seems like we are having to change our lifestyle for the ASHP.

 

Your comments are all amazingly helpful though and much appreciated.

 

One final one might be how much would it be worth if I took it out and went back to a boiler.  Cost to install £12,000

[HughF]

Midea, supplied by and plumbed according to freedom heatpumps instructions, which include the use of a plate heat exchanger.

 

a couple of days replumbing this will make it much more efficient at heating the house…

[HughF]

It’ll make about a grand on eBay, second hand…. You’d be better off spending the money on having it plumbed direct, ditch the plate heat exchanger and get the weather comp adjusted.

[M0rtimer]

22 minutes ago, HughF said:

It’ll make about a grand on eBay, second hand…. You’d be better off spending the money on having it plumbed direct, ditch the plate heat exchanger and get the weather comp adjusted.

Thank you, very useful information.

 

The system is a bit odd as we have it plumbed so that we can run a boiler as well if necessary.  (Back up)    I think that may be why there is a heat exchange, but if you can supply more information I can certainly ask the questions.

[sharpener]

Yes, a heat exchanger will introduce a temp drop between primary and secondary side you do not want. Also do you have a buffer tank, they are another cause of inefficiency.

 

If you are making changes fit a dedicated meter for the HP so you can disentangle its consumption from the rest of the house, farm, units and whatnot. Then you will be able to see properly the effect of any improvements.

 

 

Edited January 27 by sharpener

[HughF]

4 minutes ago, M0rtimer said:

Thank you, very useful information.

 

The system is a bit odd as we have it plumbed so that we can run a boiler as well if necessary.  (Back up)    I think that may be why there is a heat exchange, but if you can supply more information I can certainly ask the questions.

Bivalent systems are usually plumbed up with non return valves. The plate will be there to ensure warranty compliance with freedom heat pumps who supply midea here in the Uk.

 

Sounds like your system is working though. 6000kWh/annum isn’t much. £1800/year on backstop rate.

[SteamyTea]

54 minutes ago, M0rtimer said:

The rest is farm/business units which is why it reaches the £7200.

Can you fit a sub meter for that supply, then at least you know what is going where.

And while the power is off, fit one to monitor just the heat pump.

[JohnMo]

I found from my install of an ASHP, little changes can make a dig difference to how much electricity you use. There are several ways to have the circulation pump run, for example. Recently changed mine from continuous to intermittent as decided by the internal temperature controller. Thought it may save some energy - but just the opposite

 

An image of the electric consumption but shows the ASHP starting and stopping. The left three peaks are letting the heat pump control the circulation pump, the other wider spaced peaks are circulation pump on all the time.

 

First three peaks is the ASHP short cycling, plenty of electric going in not much heat coming out. The other two peaks show longer run times, but also long off times. It was 8 degs at the time and heat pump running very low loads.

 

The main take away from the above, is you need to take the time to understand how your heat pump is running to get the best out of it. (Most heat from least electricity).

 

Have also found leaving to run all the time let's you lower flow temperatures so you use less electricity.

Edited January 27 by JohnMo

[HughF]

31 minutes ago, sharpener said:

Yes, a heat exchanger will introduce a temp drop between primary and secondary side you do not want. Also do you have a buffer tank, they are another cause of inefficiency.

 

If you are making changes fit a dedicated meter for the HP so you can disentangle its consumption from the rest of the house, farm, units and whatnot. Then you will be able to see properly the effect of any improvements.

 

 

Midea wont be installed with a buffer. Plate or LLH depending on the year of install.

[Beelbeebub]

My 2bobs worth....

 

Is your HP set to weather compensated? You don't mention it.  That will help. 

Not keeping you warm in the cold periods: you may need to up the flow temp for the cold periods. Weather compensation will ensure that the flow temp is lower during the milder periods. 

 

The plate heat exchanger won't help. It means your HP will need to run a few degrees hotter than it migbt otherwise.  You mention it was installed to allow a boiler to also be used (it may also be to allow glycol to be used in the HP side) Is it possible to get the system replumbed so you run the HP direct and the boiler is connected via the heat exchanger?

 

Given you have an (oil?) boiler backup - you could use that for the few very cold periods when you estimate it's cheaper to run or the HP struggles.  Running the boiler a few times a year will help keep it working well and you mihbt as well use it of you've paid for it.!😁 

[HughF]

3 minutes ago, Beelbeebub said:

My 2bobs worth....

 

Is your HP set to weather compensated? You don't mention it.  That will help. 

 

Not keeping you warm in the cold periods: you may need to up the flow temp for the cold periods. Weather compensation will ensure that the flow temp is lower during the milder periods. 

 

The plate heat exchanger won't help. It means your HP will need to run a few degrees hotter than it migbt otherwise.  You mention it was installed to allow a boiler to also be used (it may also be to allow glycol to be used in the HP side) Is it possible to get the system replumbed so you run the HP direct and the boiler is connected via the heat exchanger?

 

Given you have an (oil?) boiler backup - you could use that for the few very cold periods when you estimate it's cheaper to run or the HP struggles.  Running the boiler a few times a year will help keep it working well and you mihbt as well use it of you've paid for it.!😁 

Midea WC setup is part of the install process. It should have been setup. 55@-2, 37@15 are the defaults. Graham Hendra’s ‘Lizzie’ curve, named after his wife who complained the rads were always cold.

Edited January 27 by HughF

[Andehh]

OP, i don't think your ASHP is the problem here!! You yourself have said 6000kwh in 10 months... That's pretty normal, and isn't massively far off what we're prob using with our ASHP....albeit we are a large/sprawling bungalow.

 

The ASHP doing the hot water and UFH is costing you maybe £170 a month. Yes increase the DHW to 50 degrees is a good starter if it's causing you problems. Make sure weather compensation is turned on, YouTube, asking on here or getting the installer it another installer to come out and check is worth doing.

 

The issue you have is a farm and further units costing another £5k a year in power....you need to be getting seperate meters installed so you can actually properly assess where that power is going!

 

 

Edited January 27 by Andehh