I bought a Heat Pump

Martyn1981

Mickey666 said:

Martyn1981 said:

shinytop said:

Mickey666 said:

shinytop said:

Mickey666 said:

Reed_Richards said:

Yesterday was very mild for February, my heat pump consumed 21.4 kWh of electricity in 24 hours.  My total consumption since about 10th December 2020 has been 3456 kWh which works out at 47.4 kWh per day.  My unit rate for electricity is 12.993 p per kWh so my heat pump has cost me £449 in fuel cost so far, an average of £6.16 per day. 

With an oil boiler you get no feel for day-by-day consumption but my average cost per year (over two years) was £920.  This equates to an average energy usage of 59 kWh per day assuming I got 10.35 kWh per litre of heating oil.  The worst case oil usage over December 2018 and January 2019 cost me £4.52 per day.

So so far I an paying more per day to run my heat pump, although as January this year was particularly cold it's not entirely a fair comparison.  I hope I can claw-back the difference over the milder parts of the year, which is what you would expect with a heat pump.   

Those are pretty scary figures! 
Scary for you because you've spent £17,000 installing a system that's more expensive to run than the oil alternative, implying that you'll never get any return on your investment.
Scary for everyone else because fossil fuel prices are only going to increase or be taxed into oblivion so we'll all eventually be paying similar costs to you for heating our homes.
It's not easy, or cheap, being green - though I can't help but feel the early adopters are rather paying through the nose for the privilege.

Nobody said going green was cheap.  Just look at the price of EVs.  Luckily, you and other taxpayers are funding most of my £16k ASHP central heating system installation bill.  And, for me at least, I'll be saving quite a lot vs my old NSH/immersion heater system.   If I could get 65% of the cost of an EV back from the taxpayer I'd have one like a shot.    

Like with ICE cars, we're all going to have to stop burning fossil fuels for heating eventually.  

. . . which is proof of the fundamentally uneconomic technology of ASHP systems.  Anything can be made economically attractive to the consumer if they are given grants to pay for it, and good luck to you, but it doesn't make it a sensible solution in the long term . . . at least not until the general population is lulled into paying 3x, 4x, or more than their current domestic heating costs.

I agree that burning fossil fuels will have to stop eventually, but the costs of the alternatives are going to be a huge shock.  This is why governments the world over are having to give out massive grants and subsidies to smooth the way and, hopefully, prevent rioting in the streets when people cannot afford to heat their homes despite living on an island sitting on top of centuries worth of coal.

RHI is pitched at people like me and @Reed_Richards, who had electric or oil heating.  An ASHP system is not 3-4 times more expensive to run than oil, it's broadly comparable if you use it properly.  The problem is going to be gas, simply because it's currently so cheap. But the millions of GCH systems out there are like the millions of ICE cars.  They are going to have to go and their replacements will more expensive and users will have to make changes to the way they use them.  I agree it's going to be a difficult sell, but the days of having our own personal fossil fuel burning devices are numbered.  I'm not sure if a battery powered barbecue would work though.

Spot on. And the cost benefits of heat pumps are (or can) be even higher if we consider:
1. The externality costs of FF burning, which are often ignored in simple cost comparisons, but will become more significant as carbon prices rise to reflect the real costs.

Not forgetting the reduction/removal of government subsidies that currently hide the real costs of heat pumps

2. The use of cheap rate leccy can reduce the costs significantly, and through the winter provide an excellent demand for wind generation. I'd have thought 10p/kWh was a sensible upper figure for E7 rates, with many paying much less.

Though of course the daytime rates will consequently be higher so unless you only want to heat your home through the night the overall costs may not be reduced very much, indeed it's possible they would be increased.

3. PV - goes without saying really. We can't produce our own oil or gas cheaply, but we can generate our own leccy, and whilst its contribution in the worst 3 heating months will be small, it can provide a significant amount (perhaps even all) heating for the 'better' 4 heating months (Mch, Apr, Sep & Oct), plus of course all DHW for the warmer 9(ish) months.

4. On a personal level, you can even consider investing in some RE generation schemes to meet your leccy demand on a net basis, thereby taking some personal responsibility ....... and having fun.

4 - 'having fun' seems to be a significant driver for these 'green' technologies, or 'alternative technology' as they used to be called.  And I agree.  It's certainly what switched me on to investigating such things and playing around with old radiators, pumps, pipework to experiment solar thermal panels and programming microcontrollers to measure, control and calculate energy flows.  It IS fun, trying to capture useful energy for free . . . except that it isn't 'free' at all and when I took off my 'fun' hat and looked into the hard economic realities of installing and running such systems in a practical domestic environment, they didn't pass the test.  The very fact that government subsidies are needed to persuade most people to make such choices is proof of that.

Of course, the economics will likely change (or be more widely manipulated by taxes and subsidies) in the coming decades, but in the meantime, apart from 'having fun' there seems little financial incentive for these 'alternative' technologies and the early adopters, as ever, will be the ones paying the high price.

Hiya, I think you may have gotten yourself a bit confused there, so I'll try to explain for you.

Point 1. I think you mised the big picture. You refer to subsidies and government support that help RE, but just to be clear, these are actually due to FF externality costs. If FF wasn't subsidised, be it in actual terms, or from the omission of externality costs, then RE wouldn't need artificial support. Earlier you tried to compare costs without including FF externalities, now you are effectively making the same mistake by wrongly attributing AGW avoidance costs on RE, when the costs are actually due to FF's. So you should compare to higher 'real' FF costs, or accept RE subsidies to balance FF subsidies, but missing both cases is a tad myopic.

Point 2. Simple mistake you've made there, but still worth clarifying. You are assuming that leccy demand is spread evenly across the two E7 rates (cheap night and more expensive day), but of course that's not how a rational human being would act. You would want to maximise demand on the E7 period and minimise the higher rate (also all DHW should be on E7 timings).
Now, of course that's not possible on the coldest days, when you may need to heat 24/7, but at other times it is possible. In fact, just my own mini-hybrid experimentation has meant E7 only heating at night since early Mch, and non at all since late Mch (explain more later).
You also need to consider the cross benefits - by increasing your leccy consumption (via heat pump) to a point where E7 is viable, you can then shift additional duties onto it, such as dishwasher, washing machine etc.. And when you switch to a BEV (G&E board after all) you will be able to put 100% onto the E7 (or 50% (explain later too)), again benefiting from the move to a higher consumer.

Point 3 (as promised I'd explain later). With PV, you will reduce leccy consumption during the daytime for heat pump use, raising the benefits of E7. That's how my heating was E7 only since early Mch, non import since late Mch.
Since (as you pointed out) an E7 deal means a higher day rate, then PV reduces daytime import, thus reducing the 'penalty' and improving the E7 economics.
And in my case the BEV's are 50% (~1,000kWh) E7, and 50% PV, as they are charged at night in the bottom 6 months, and off a granny charger on PV during the better 6 months.
So a G&E package (heat pump, BEV and PV) appears to enhance the benefits of E7, and vice versa.

Point 4. Again you got yourself totally confused I'm afraid. Your entire response seems to be based on the throwaway remark at the very end (missing the real point), and sadly you seem to miss that I'm referring to additional RE 'scheme' investments. These are additional to home improvements, such as investing in solar farms, wind farms, hydro projects, AD, multi property upgrades etc etc (I'm invested in around 30 such schemes).
This is fun, and economical, and as I explained (sorry I didn't explain more carefully for you) is a way for folk, especially those with a G&E mindset, to attempt to account/offset more of their energy consumption, be it direct use, or through goods and services consumed.

Lastly, and I was heartened to read or at least interpret some of your comments this way, but you seem to be saying that once the economics change, or are manipulated in such a way as to make the cost of your energy reflect their true costs, then you will be minded to switch. Obviously it would be better news to hear that you wanted to make a change now, for the right reasons, but it's nearly as good to know that folk like yourself will switch once the true economics impact you personally.

I hope you have great fun with RE and cleaner, greener technology once its to your financial benefit. Enjoy.

TheMaster_2

I had a Mitsubishi Ecodan ASHP installed last year, I also installed solar and batteries.
I don't think my house is particularly a warm house anyway. Although it's never warm enough for the other half anyway no matter what the temperature is!
I have noticed a huge difference with the ASHP compared to my old gas heating system, the house is colder downstairs. I have tried different flow temperatures. Downstairs just does not get warm to 3 radiators for some reason I have had to add some electric fan heaters for use on the coldest days, they think it's the pipework. Upstairs gets nice and warm though. The installers have been back a few times but not resolved the issue (yet!). I think the only option may be to dig up the concrete floor and run some new pipework for the downstairs rads.
I have the same make tank as the OP, originally they were supposed to install a 250ltr tank. but installed a 175 by mistake, they did come back and put a 220ltr horizontal in as the 250ltr would not fit. However, the tank loses about .5 degrees per hour in temperature for the hot water.
I don't think they are cheap to run by any means here are my Jan and Feb usage, also not showing on here are the additional electric heaters I have had to install downstairs.

TheMaster_2

Can anyone recommend an installer for underfloor heating, it's my next thought about getting some warmth downstairs

Reed_Richards

TheMaster_2 said:

I had a Mitsubishi Ecodan ASHP installed last year, I also installed solar and batteries.....
I have noticed a huge difference with the ASHP compared to my old gas heating system, the house is colder downstairs. I have tried different flow temperatures. Downstairs just does not get warm to 3 radiators for some reason I

You imply (by not mentioning it) that you did not get new radiators when you got the heat pump.  If so that was probably a big mistake as it is unlikely that your existing radiators have enough output at the lower water temperature that the heat pump provides.  Nonetheless, the problem you describe has a standard solution that applies to all central heating systems, whatever the "boiler".  The standard solution is to adjust the radiator valves to reduce the flow rate to the "hot" radiators and increase the flow rate to the "cold" radiators (assuming those radiator valves are not already fully open).  If you have Thermostatic Radiator Valves you can adjust these to achieve the same effect but upstairs will have to reach temperature before downstairs warms up.

I replaced almost all my radiators but chose not to replace the radiator in my kitchen because of lack of wall space, despite the fact that the calculations said that I needed one with a bigger surface area.  The consequence is that first thing in the morning the kitchen can be a bit chilly.  It warms-up during the day but more slowly than the other rooms in the house. 

Sadly, if you replaced a gas boiler with a heat pump you will find yourself paying more to heat your house . If you were told otherwise you were mis-sold the heat pump.  

Cardew

My 180 ltr  tank specification is to 'lose' 1.3kWh a day with water @ 65C. it is 'B' rated so 'A' or higher rating will lose less.

As said above that heat is not 'lost' for much of the year as it warms the fabric of the house.

Reed_Richards

I suspect these tank ratings are made without any water pipes attached and in practice you can get much worse if the pipes are not very well-insulated.  

matelodave

When you've determined the heat requirements of the room,there is a simple calculation to check if a radiator will provide sufficient heat output. You must check the “delta T”.

​What is the "delta T"?

In most radiator cataloguse, a heat output figure is provided, along with the radiator's dimensions. The heat output figure is reported for a specific "delta T". The delta T is the difference between a target room temperature and the average temperature of water in the radiator. The average temperature of the radiator depends on the temperature of the water entering and leaving the radiator, which may be different in your heating system. An average radiator temperature of 50 degrees implies a 55 degree flow and 45 degree return, however to get a DeltaT of 50 dgrees the average radiator temperature has to be 70 dgrees.

delta T = (Room temperature) - (Average radiator water temperature) which is not the same as the average radiator temperature
If you want a room temperature of 20 degrees and the average radiator temperature is 50 degrees then your Delta T is actually only 30 degrees

If the delta T of your system is different from the one shown in the catalogue, then you will need to calculate a new heat output. This is done by multiplying the output figure in the catalogue by a correction factor. Be aware than many radiators are still specified at a deltaT or 60 or even 70 degrees.

​Correction factor table

Delta T (°C)	Correction factor
5	0.050
10	0.123
15	0.209
20	0.304
25	0.406
30	0.515
35	0.629
40	0.748
45	0.872
50	1.000
55	1.132
60	1.267
65	1.406
70	1.549
75	1.694

From the above you can see that a rad spec'd at 1000w will only deliver 515 watts with a deltaT of 30 degrees so it needs to be sized correctly for the heat required to ensure that reheat times are acceptable or that it can actually acheive the required room temperatures. In some cases pipework may need to be uprated to accomodate the higher flow rates required by a heatpump.

Reed_Richards

matelodave said:

From the above you can see that a rad spec'd at 1000w will only deliver 629watts ...

Is that right?  You're using the figure for delta T = 35 C so if the room temperature is 20 C that implies an average water temperature of 55 C which presumably would be 60 flow and 50 return.  If it's 55 C and 45 C then delta T would be 30 C and the radiator output would be 515 W.  In my case my specified conditions are 50 C flow and 45 C return so I would be getting about 465 W (estimated), less than half the delta T = 50 value.

Edit.  I have just checked and my installer used a divisor of 2.4 to convert from the Delta T = 50 C values, so that would be a multiplier of 0.417, just above the 25 C value in the table.

matelodave

TheMaster_2 said:

I had a Mitsubishi Ecodan ASHP installed last year, I also installed solar and batteries.
I don't think my house is particularly a warm house anyway. Although it's never warm enough for the other half anyway no matter what the temperature is!
I have noticed a huge difference with the ASHP compared to my old gas heating system, the house is colder downstairs. I have tried different flow temperatures. Downstairs just does not get warm to 3 radiators for some reason I have had to add some electric fan heaters for use on the coldest days, they think it's the pipework. Upstairs gets nice and warm though. The installers have been back a few times but not resolved the issue (yet!). I think the only option may be to dig up the concrete floor and run some new pipework for the downstairs rads.
I have the same make tank as the OP, originally they were supposed to install a 250ltr tank. but installed a 175 by mistake, they did come back and put a 220ltr horizontal in as the 250ltr would not fit. However, the tank loses about .5 degrees per hour in temperature for the hot water.
I don't think they are cheap to run by any means here are my Jan and Feb usage, also not showing on here are the additional electric heaters I have had to install downstairs.

If your rads werent replaced then you'll never get a sufficient heat out of them without using the back-up/boost heater as most ASHP will only get up to around 55 degrees. I doubt the size of the tank has a great deal to do with your heating problems.

Mickey666

Martyn1981 said:

Mickey666 said:

Martyn1981 said:

shinytop said:

Mickey666 said:

shinytop said:

Mickey666 said:

Reed_Richards said:

Yesterday was very mild for February, my heat pump consumed 21.4 kWh of electricity in 24 hours.  My total consumption since about 10th December 2020 has been 3456 kWh which works out at 47.4 kWh per day.  My unit rate for electricity is 12.993 p per kWh so my heat pump has cost me £449 in fuel cost so far, an average of £6.16 per day. 

With an oil boiler you get no feel for day-by-day consumption but my average cost per year (over two years) was £920.  This equates to an average energy usage of 59 kWh per day assuming I got 10.35 kWh per litre of heating oil.  The worst case oil usage over December 2018 and January 2019 cost me £4.52 per day.

So so far I an paying more per day to run my heat pump, although as January this year was particularly cold it's not entirely a fair comparison.  I hope I can claw-back the difference over the milder parts of the year, which is what you would expect with a heat pump.   

Those are pretty scary figures! 
Scary for you because you've spent £17,000 installing a system that's more expensive to run than the oil alternative, implying that you'll never get any return on your investment.
Scary for everyone else because fossil fuel prices are only going to increase or be taxed into oblivion so we'll all eventually be paying similar costs to you for heating our homes.
It's not easy, or cheap, being green - though I can't help but feel the early adopters are rather paying through the nose for the privilege.

Nobody said going green was cheap.  Just look at the price of EVs.  Luckily, you and other taxpayers are funding most of my £16k ASHP central heating system installation bill.  And, for me at least, I'll be saving quite a lot vs my old NSH/immersion heater system.   If I could get 65% of the cost of an EV back from the taxpayer I'd have one like a shot.    

Like with ICE cars, we're all going to have to stop burning fossil fuels for heating eventually.  

. . . which is proof of the fundamentally uneconomic technology of ASHP systems.  Anything can be made economically attractive to the consumer if they are given grants to pay for it, and good luck to you, but it doesn't make it a sensible solution in the long term . . . at least not until the general population is lulled into paying 3x, 4x, or more than their current domestic heating costs.

I agree that burning fossil fuels will have to stop eventually, but the costs of the alternatives are going to be a huge shock.  This is why governments the world over are having to give out massive grants and subsidies to smooth the way and, hopefully, prevent rioting in the streets when people cannot afford to heat their homes despite living on an island sitting on top of centuries worth of coal.

RHI is pitched at people like me and @Reed_Richards, who had electric or oil heating.  An ASHP system is not 3-4 times more expensive to run than oil, it's broadly comparable if you use it properly.  The problem is going to be gas, simply because it's currently so cheap. But the millions of GCH systems out there are like the millions of ICE cars.  They are going to have to go and their replacements will more expensive and users will have to make changes to the way they use them.  I agree it's going to be a difficult sell, but the days of having our own personal fossil fuel burning devices are numbered.  I'm not sure if a battery powered barbecue would work though.

Spot on. And the cost benefits of heat pumps are (or can) be even higher if we consider:
1. The externality costs of FF burning, which are often ignored in simple cost comparisons, but will become more significant as carbon prices rise to reflect the real costs.

Not forgetting the reduction/removal of government subsidies that currently hide the real costs of heat pumps

2. The use of cheap rate leccy can reduce the costs significantly, and through the winter provide an excellent demand for wind generation. I'd have thought 10p/kWh was a sensible upper figure for E7 rates, with many paying much less.

Though of course the daytime rates will consequently be higher so unless you only want to heat your home through the night the overall costs may not be reduced very much, indeed it's possible they would be increased.

3. PV - goes without saying really. We can't produce our own oil or gas cheaply, but we can generate our own leccy, and whilst its contribution in the worst 3 heating months will be small, it can provide a significant amount (perhaps even all) heating for the 'better' 4 heating months (Mch, Apr, Sep & Oct), plus of course all DHW for the warmer 9(ish) months.

4. On a personal level, you can even consider investing in some RE generation schemes to meet your leccy demand on a net basis, thereby taking some personal responsibility ....... and having fun.

4 - 'having fun' seems to be a significant driver for these 'green' technologies, or 'alternative technology' as they used to be called.  And I agree.  It's certainly what switched me on to investigating such things and playing around with old radiators, pumps, pipework to experiment solar thermal panels and programming microcontrollers to measure, control and calculate energy flows.  It IS fun, trying to capture useful energy for free . . . except that it isn't 'free' at all and when I took off my 'fun' hat and looked into the hard economic realities of installing and running such systems in a practical domestic environment, they didn't pass the test.  The very fact that government subsidies are needed to persuade most people to make such choices is proof of that.

Of course, the economics will likely change (or be more widely manipulated by taxes and subsidies) in the coming decades, but in the meantime, apart from 'having fun' there seems little financial incentive for these 'alternative' technologies and the early adopters, as ever, will be the ones paying the high price.

Hiya, I think you may have gotten yourself a bit confused there, so I'll try to explain for you.

Point 1. I think you mised the big picture. You refer to subsidies and government support that help RE, but just to be clear, these are actually due to FF externality costs. If FF wasn't subsidised, be it in actual terms, or from the omission of externality costs, then RE wouldn't need artificial support. Earlier you tried to compare costs without including FF externalities, now you are effectively making the same mistake by wrongly attributing AGW avoidance costs on RE, when the costs are actually due to FF's. So you should compare to higher 'real' FF costs, or accept RE subsidies to balance FF subsidies, but missing both cases is a tad myopic.

Point 2. Simple mistake you've made there, but still worth clarifying. You are assuming that leccy demand is spread evenly across the two E7 rates (cheap night and more expensive day), but of course that's not how a rational human being would act. You would want to maximise demand on the E7 period and minimise the higher rate (also all DHW should be on E7 timings).
Now, of course that's not possible on the coldest days, when you may need to heat 24/7, but at other times it is possible. In fact, just my own mini-hybrid experimentation has meant E7 only heating at night since early Mch, and non at all since late Mch (explain more later).
You also need to consider the cross benefits - by increasing your leccy consumption (via heat pump) to a point where E7 is viable, you can then shift additional duties onto it, such as dishwasher, washing machine etc.. And when you switch to a BEV (G&E board after all) you will be able to put 100% onto the E7 (or 50% (explain later too)), again benefiting from the move to a higher consumer.

Point 3 (as promised I'd explain later). With PV, you will reduce leccy consumption during the daytime for heat pump use, raising the benefits of E7. That's how my heating was E7 only since early Mch, non import since late Mch.
Since (as you pointed out) an E7 deal means a higher day rate, then PV reduces daytime import, thus reducing the 'penalty' and improving the E7 economics.
And in my case the BEV's are 50% (~1,000kWh) E7, and 50% PV, as they are charged at night in the bottom 6 months, and off a granny charger on PV during the better 6 months.
So a G&E package (heat pump, BEV and PV) appears to enhance the benefits of E7, and vice versa.

Point 4. Again you got yourself totally confused I'm afraid. Your entire response seems to be based on the throwaway remark at the very end (missing the real point), and sadly you seem to miss that I'm referring to additional RE 'scheme' investments. These are additional to home improvements, such as investing in solar farms, wind farms, hydro projects, AD, multi property upgrades etc etc (I'm invested in around 30 such schemes).
This is fun, and economical, and as I explained (sorry I didn't explain more carefully for you) is a way for folk, especially those with a G&E mindset, to attempt to account/offset more of their energy consumption, be it direct use, or through goods and services consumed.

Lastly, and I was heartened to read or at least interpret some of your comments this way, but you seem to be saying that once the economics change, or are manipulated in such a way as to make the cost of your energy reflect their true costs, then you will be minded to switch. Obviously it would be better news to hear that you wanted to make a change now, for the right reasons, but it's nearly as good to know that folk like yourself will switch once the true economics impact you personally.

I hope you have great fun with RE and cleaner, greener technology once its to your financial benefit. Enjoy.

Good reply, but it really only serves to highlight the 'philosophical' nature of many of these issues rather than the simple economic ones (because there are no simple ones)

AGW is a big topic alright, so big that I (and many others) have doubts about how the so-called 'true costs' of FF are calculated.  Economics is a complex enough subject at the best of times and is basically too complex for anyone to understand and control - if it was then governments, with all their expert advisors, would do a better job in managing their economies.

And if it is too complex for governments/professionals to fully understand then it's way beyond the Man-on-the-Clapham-Omnibus.  So how does that man make sense of all this complexity?  They focus on their own financials, and at the domestic level these 'alternative technologies' rarely make any economic sense.  If they did, there would be a mad rush to adopt them.

Meanwhile, those on a mission to save the planet might be more effective by concentrating on promoting wider contraception with the aim of stabilising and eventually reducing our global population.  Because as far as I can see, our 'western' standard of living is already way above the sustainable capacity of the planet (ecological footprint) and there's little sign of it reducing anytime soon.  Then factor in the other 50% of the planet with aspirations to grow their own standards of living to equal ours (and why shouldn't they?!) and it's easy to see why the planet is in trouble.  And it's a far bigger issue than just FF usage.

“All our environmental problems become easier to solve with fewer people, and harder — and ultimately impossible — to solve with ever more people.”

 – Sir David Attenborough, Population Matters patron

https://populationmatters.org/