Old air source heat pump

Luketum92

Sorry 4 kwh cheaper than my mums

tacpot12

I'll freely admit I have little knowledge about ASHPs, but the installer's comments seem unhelpful and self-serving. How is it "a mess"? I find it frustrating when so called experts provide so little expertise! 

The fact that the compressor feet are broken and need replacing seems to be unrelated to the poor performance - the feet are just rubber mounts that dampen vibration. I'm guessing the installer wants the work of installing a new system rather than spending time figuring out why the current system is underperforming. I think I would try another installer because if the alternative is a new system, that is going to be many thousands of pounds. In the short term, portable heaters offer some respite to get her through the winter. 

Longer term, the property may need more insulation. What did the EPC say about the energy performance of the property? 

rosiesposies

I currently work for and have worked for another heat pump manufacturer; whoever said it’s a black art isn’t wrong. When they are specified properly, they are gold. When they aren’t, it’s a nightmare and unfortunately you will have little recourse from the pump manufacturer, it’s rare the pumps themselves are to blame. If the whole system isn’t working in harmony; ie voltage supply, pump, and sized correctly, something will go wrong. The pump will have to work harder to heat the space, draw more kWh and so on. Being undersized for the property is the fault of the specifying installer, not a manufacturing fault of the pump itself. IMO get an independent renewable heating company out, who has been in business for longer than the original grant in late 2000s who installers systems from different manufacturers. The government grants cause all sorts of cowboy outfits to appear overnight, and you do not need extra qualifications to install or spec these things. There are adr bodies that can help. 

It would be cheaper to put in electric shower and temporary space heating whole this is sorted 

Cardew

bob_a_builder said:

There was case some time ago where a whole estate was fitted with the Nibe ones but they all had to be ripped out - had been underspeced ?
There was a whole series of videos over the course of the issue
https://www.youtube.com/watch?v=DJr_oPXRYl0&t=26s&ab_channel=jasonoldy69

There were loads of posts on MSE about these NIBE exaust heat pumps costing a fortune to run. Like matelodave in his post I thought they were all in rental properties.

See: https://forums.moneysavingexpert.com/search?Search=NIBE+Fighter+360p

I fear there is no solution to your mother's problem, other than to rip it out and install another system.

Talldave

Electricity is available for under 11p per kWh so there's no reason to be paying silly money.

Gerry1

Luketum92 said:

Unfortunately  there is no gas mains, the cheapest tariff I can find is 14.50 a kwh no idea how you are getting around 4 kwh

How did you search?  As previously mentioned, is she paying by direct debit ?  Tell us the distribution area or the first part of the postcode and someone may be able to suggest something better.

matelodave

Hi Luke,
I'm not doubting your figures for consumption but I would like to understand what you are measuring and how you are measuring it.
My suspicion is that you are looking at you IHD and possibly not getting a full picture or understanding of what is going on.
If you are measuring at the IHD then you have to bear on mind that you'll also be measuring everything else in the house thats is in operation and the time you measure it - fridges, freezers, lights, kettle etc so your estimate may not actually be truly representative of the heatpump consumption.
Likewise a short measuring period wont always take into account of the effects of thermostats and other influences on the unit so you need to be a bit more scientific in your approach to get a better fee for what is going on and what effect that tweaks and adjustments are making. Watching the video that I put up (rather than the scary ones from the BBC) should give you a reasonable starting point however, dont keep fiddling with it. Heatpumps are very slow to respond and can easily take 4-8 hours to get the room up to temperature so cranking it up and down every few hours wont help you understand the effects of any adjustments..

Set it as advised and then leave it for at least a day, preferably two for the temperatures to settle - read and record the leccy meter  every day at the same time to find out how much energy your mum is is using in 24 hours (dont forget it will include lights, cooking TV and everything else) - dont use the IHD unless you have checked that it really does show the reading on the meter.
Dividing the 24 hour consumption by 24 will give you a much better feel of her hourly consumption as it's getting averaged out over 24 hours.

Also do it over 7 days to try and smooth out daily variations bearing in mind that the weather is all over the place at this time of the year so you are trying to see what is going on over a period.

You can then make SMALL adjustments (only 1 or 2 degrees) after a couple of days and, keeping to your daily measuring regime, see how it affects the comfort and consumption. Dont forget to note whether the cooker, kettle, washing machine or other stuff has been used as these will affect you measurements but cant be attributed to the heatpump. Don't turn it off overnight because it will then flog it's heart out when it comes on to try and recover the lost heat, probably using the boost heater. You should aim for an even temperature with possibly a set back of just 1-2 degree overnight.

My system only sets back to 17/18 degrees but still takes around 6 hours to get the temperature up to 19-20 when its really cold outside like is was earlier this week. If I turn it off overnight it can take 24-36 hours to reheat the place. I can make it do it faster but the leccy consumption rockets so I just let it idle away continuously under the control of programmable room thermostats. My system is different to yours but the principle is still the same however it extracts heat from outside which is much more variable than an exhaust unit like yours which relies on warm air from inside. So if you let the house get cold, the heatpump has to work a lot harder than if it stays warm.

David28

Talldave said:

Electricity is available for under 11p per kWh so there's no reason to be paying silly money.

Not in Hydro Electric area

Talldave

David28 said:

Talldave said:

Electricity is available for under 11p per kWh so there's no reason to be paying silly money.

Not in Hydro Electric area

Maybe 12.99p then?

Luketum92

So after speaking to the nibe manufacturers I have found out that the exhaust air source heat pump was sold apart of a large sale to building developers and the unit I have in my mums home is ment for a one bed apartment/small house and not for a 2 bed house so it has to work extra hard to maintain a constant temperature i have spoken to the residents on the street and the minimum people pay in the summer is around 130-150 pounds a week, in the winter its always above 200 pounds a month nearer the 300 pound mark does anyone have any advice on how my mum could get a grant of any sort to get this thing ripped out and replaced she's a pensioner on benefits?