# The cost of using heat pumps.

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Just been comparing the net present cost (NPC) of my previous domestic combined gas and electricity costs.

The last quarter   -  December 2020  to February 2021

Historically  a fairly conventional gas boiler and hot water domestic heating. Electric lighting and sundry domestic power requuirements.

2016 Gas boiler replaced by an air source heat pump.

Combined gas and electricity costs.

Old system NPC cost  (ie bills would have been at todays prices)  ~ £560

Current system  actual costs  ~ £660

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I'm not clear if your current system costs are purely running costs, or if they include the capital cost of the heat pump and, if the latter, over what period you have amortised it. I'm interested since I'm considering installing such a system.

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Do you need gas any more or not?

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41 minutes ago, Area54 said:

I'm not clear if your current system costs are purely running costs, or if they include the capital cost of the heat pump and, if the latter, over what period you have amortised it. I'm interested since I'm considering installing such a system.

I am happy to provide all the detail you like since there is a lot of twaddle still being promoted about these things.

The costs in my first post are simply the payments to the gas and electric companies, including their dramatically increasing standing charges and the VAT that the EU forced a former Chancellor to levy.

In 2016 my old boiler, which had been staggering on for quite a few years, conked out completely.
So I had to replace it anyway. This would have cost around £3,000

I chose an air to hot water system since I already had a hot water radiator system.
However I took the opportunity to upgrade the plumbing for a couple of reasons.
The gas boiler, originally installed in 1988 was the then largest instaneous heater on the market.
No heat pump can match that performance, so all require some form of buffer tank.
I added two 500L tanks, one for the CH and on efor the DHW, and all the asscoiated pipework, pumps and automated valves and controls.
Heat pump radiaters typically operate at lower water temperatures so some rads were also upgraded to larger ones.

So I engaged out wonderful governments preferred 'installer of the year' to manufacture and install a British made one for £8,000.
Sadly that is an accolade to avoid and they went bust in 2018.

I also received one of the alternative energy installation grants of £5600, receivable over 7 years.
So by the end of that I will have spent about the same in capital terms as if I had simply replaced the boiler.

For the first 3 years the combined electricity and gas costs were lower with the heat pump. This year has been the first with the pump markedly more expensive.

Up to 2016 the principal consumer in the house was the gas boiler, but we also have a gas hob.
Now the heat pump is the principal energy consumer and I only need about 10 cubic feet of gas a year.

It is actually rather galling to receive a gas bill bot £1.50 worth of gas plus £28.50 worth of standing charge.

Edited by studiot
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This is very useful. Thank you.

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58 minutes ago, studiot said:

For the first 3 years the combined electricity and gas costs were lower with the heat pump. This year has been the first with the pump markedly more expensive.

Unexpected weather? Or efficiency drop? Or you some unexpected maintenance?

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Yeah, I think they're being pushed more to curb UK's imports, but have been decently successful by the looks of things. May or may not be cheaper for consumer, though also have to factor in environmental concerns.

Would definitely look into what Danijel mentioned.

Is it possible to directly buy the fuel you need for your cooking needs and reduce your bill that way some? Reading that some can also opt of the standing charge in exchange for paying more for what they do use. Might be an option as well.

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1 hour ago, Danijel Gorupec said:

Unexpected weather? Or efficiency drop? Or you some unexpected maintenance?

10 minutes ago, Endy0816 said:

Yeah, I think they're being pushed more to curb UK's imports, but have been decently successful by the looks of things. May or may not be cheaper for consumer, though also have to factor in environmental concerns.

Would definitely look into what Danijel mentioned.

Is it possible to directly buy the fuel you need for your cooking needs and reduce your bill that way some? Reading that some can also opt of the standing charge in exchange for paying more for what they do use. Might be an option as well.

The UK economy has the front wheels bogged down in official bureaucracy,
and the back wheels are mired in the sharp practices of the marketeers and bean counters.

The change has simply been due to the deliberate change in pricing in that time.
There is nothing free market about the UK utilities industries, despite claims by the politicians who made them the pigs ears they are today.

Hi.

Can you instead of comparing the cost$for time lapses, tell/compare KWh of consumption for the lapses ? My local energy is supplied typically by gas and/or electric. Eliminated the gas years ago and am using electric heat only, because the gas company wanted to charge a monthly minimum even for zero consumption to 'maintain' the account during ~8 not-cold months of the year. So kicked them out in 2016, not willing to 'maintain' their pockets besides peace of mind with no gas in the dwelling. Make sure you are not in that kind of trap, or utilities 'policy' changes. (Am heating only the rooms in use, 3 bedrooms have heating shut off and closed doors) As other means of not wasting heat and money. ##### Link to comment ##### Share on other sites 1 hour ago, Externet said: Can you instead of comparing the cost$ for time lapses, tell/compare KWh of consumption for the lapses ?

Some of the gas energy is wasted through the chimney of your home. So I don't think the kWh comparison would be fair (it could be more fair if you count how much energy was wasted during production of electric energy).

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2 hours ago, Externet said:

Hi.

Can you instead of comparing the cost\$ for time lapses, tell/compare KWh of consumption for the lapses ?

My local energy is supplied typically by gas and/or electric.  Eliminated the gas years ago and am using electric heat only, because the gas company wanted to charge a monthly minimum even for zero consumption to 'maintain' the account during ~8 not-cold months of the year.  So kicked them out in 2016, not willing to 'maintain' their pockets besides peace of mind with no gas in the dwelling.

Make sure you are not in that kind of trap, or utilities 'policy' changes.

(Am heating only the rooms in use, 3 bedrooms have heating shut off and closed doors) As other means of not wasting heat and money.

Yes I have electricity and gas records, both financial and supply units, going back to 1987 when we moved into this house.
Years vary and it is easy to pick out the hard winters plotting annual figures year by year.
Averages are also good for other purposes.
Better for comparison with other situations (eg I don't think Area54 has access to mains gas and LPG offers different performance figures).

Utilities like setting up 'deals' and 'packages' and 'policy'  -  which can help them avoid (some) obligations under the UK Gas and Electricity supply Acts.
This is why I have never sought or agreed to a change of terms under the original supply orders with the original supply organisations. The Acts in force at the time were binding on the original suppliers and their successors in title.

Yes one of the upgrades to the central heating radiatior system was to split the heating into 2 zones.
In my case upstairs and downstairs.
These zones can be programmed to come on at different times and different temperatures and fall back to different temperatures when not in use.
This part of the system has worked very well indeed.

55 minutes ago, Danijel Gorupec said:

Some of the gas energy is wasted through the chimney of your home. So I don't think the kWh comparison would be fair (it could be more fair if you count how much energy was wasted during production of electric energy).

Yes, many factors are involved. The efficiency of the boiler varies with the humidity (and slightly the temperature) of the air, its own calorific value (which varies from time to time and the gas company has to publish in the bill), its state of internal cleanliness and of course as you say some of the heat necessarily is taken carrying away the exhaust gases and water vapour. Some of this is recovered as heat storage in the masonry of the chimney stack.

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• 8 months later...

All the indicators point to the UK government favouring heat pumps over gas boilers for political rather than economic reasons. They don't trust Russia, or Belarus or Ukraine to keep the gas flowing, and likewise an independent Scotland. Also, they see heat pumps as a vote winner with the save-the-planet crowd. Purely on economic grounds, air source heat pumps don't really cut it, for most of the UK consumers.

People who install the heat pumps often have to massively improve the insulation of their property, otherwise they will be cold in cold weather. Then, when they get it installed, they mistakenly give the credit for supposedly improved bills to the heat pump, rather than the money spent on insulation.

If people just did the insulation, and stuck with a gas boiler or got a new efficient one, they would instantly see an improvement in their bills.

What the government are doing is taking money from taxpayers, giving it to heat-pump buyers, and hoping to buy votes with it.

Ground source heat pumps, in off-the-gas-grid areas, might make economic sense in the long term, but air source ones just don't cut it without massive economic redistribution via taxes and grants.

In any case, where will all the electricity come from, to run it all? All the cars, all the buses and all the vans and trucks will need juice off the grid. If you add all the heating for all the buildings, you will need a heck of a lot of power generation. And you need it 24/7, not just when the wind blows, or the sun is shining.

The way it's going, I would be investing in a lot more nuclear, and a lot more onshore wind in the UK. Forget the protesters. I like wind towers myself, and the moaners will soon shut up once they are used to them. Who likes electricity pylons? But we got used to them years ago, and now people hardly notice them.

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5 minutes ago, mistermack said:

Purely on economic grounds, air source heat pumps don't really cut it, for most of the UK consumers.

What experience and figures do you present to back up this claim ?

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16 minutes ago, studiot said:

What experience and figures do you present to back up this claim ?

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My own idea regarding heat pumps is to add two giant insulated water storage units to each new house build. They could be sited under a yard, or garden or drive. One for hot water, and the other for cold. In the summer, you use solar heat to heat the hot water unit. Also waste heat from any air conditioning system. At the same time, you use the cold water unit for ambient cooling, and cooling the AC unit.

Then in winter, you use the hot water unit, hot from the summer heating, for direct heating or for use with a heat pump. And cool the cold water tank through an external heat exchanger with a fan.

Once the water storage units were installed, they would make AC and heat pump heating very efficient, and so add a heap of value to the property. Hopefully the added value would be more than the cost of installing the units, and if you add in money saved on bills, there would be a substantial net profit after a few years. Also of course, they would save plenty of fossil fuel through the free stored heat energy and free stored cooling.

The bigger you made the water storage tanks, the less they would cost in proportion to heat or cold stored. Maybe they could make a tank big enough to serve a whole street when building a new estate.

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12 hours ago, mistermack said:

My own idea regarding heat pumps is to add two giant insulated water storage units to each new house build. They could be sited under a yard, or garden or drive. One for hot water, and the other for cold. In the summer, you use solar heat to heat the hot water unit. Also waste heat from any air conditioning system. At the same time, you use the cold water unit for ambient cooling, and cooling the AC unit.

Then in winter, you use the hot water unit, hot from the summer heating, for direct heating or for use with a heat pump. And cool the cold water tank through an external heat exchanger with a fan.

Once the water storage units were installed, they would make AC and heat pump heating very efficient, and so add a heap of value to the property. Hopefully the added value would be more than the cost of installing the units, and if you add in money saved on bills, there would be a substantial net profit after a few years. Also of course, they would save plenty of fossil fuel through the free stored heat energy and free stored cooling.

The bigger you made the water storage tanks, the less they would cost in proportion to heat or cold stored. Maybe they could make a tank big enough to serve a whole street when building a new estate.

12 hours ago, mistermack said:

My own idea regarding heat pumps is to add two giant insulated water storage units to each new house build. They could be sited under a yard, or garden or drive. One for hot water, and the other for cold. In the summer, you use solar heat to heat the hot water unit. Also waste heat from any air conditioning system. At the same time, you use the cold water unit for ambient cooling, and cooling the AC unit.

Then in winter, you use the hot water unit, hot from the summer heating, for direct heating or for use with a heat pump. And cool the cold water tank through an external heat exchanger with a fan.

Once the water storage units were installed, they would make AC and heat pump heating very efficient, and so add a heap of value to the property. Hopefully the added value would be more than the cost of installing the units, and if you add in money saved on bills, there would be a substantial net profit after a few years. Also of course, they would save plenty of fossil fuel through the free stored heat energy and free stored cooling.

The bigger you made the water storage tanks, the less they would cost in proportion to heat or cold stored. Maybe they could make a tank big enough to serve a whole street when building a new estate.

21 hours ago, mistermack said:

and stop hijacking mine with off topic material  ?

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1 hour ago, studiot said:

and stop hijacking mine with off topic material  ?

In case you hadn't noticed, I was proposing a way of making heat pumps more efficient. That's certainly not a hijack by any stretch of the imagination. Even yours, I would have thought since the title of the thread is " The cost of using heat pumps"   !!

And since you asked for figures and experience to back up my claim that air source heat pumps don't cut it, economy-wise, you only have to look at your own example as posted, where £8,000 was spent, achieving an effective INCREASE in bills of £100.

If you think that is cutting it, you need to brush up on your maths.

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I am curious.
Studiot, when you got a hat pump installed, did you also upgrade the insulation?

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1 hour ago, John Cuthber said:

I am curious.
Studiot, when you got a hat pump installed, did you also upgrade the insulation?

I can't resist this, although google fought man and boy to resist offering anything for hat pump.

Yes some extra loft insulation was done but things like cavity wall, high grade double glazing, swapping old metal frames for solid mahogany, underfloor insulation were all done years before the heat pump.
No costs of the extra loft insulation were included in the opening post.

Edited by studiot
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I live in South Dakota,  which has bitter winters with regular blasts of Arctic air,  so heat pumps still seem problematic here.  I doubt the external air has much available heat at minus 20 F. (-29 C.)

I have recently considered switching to electric furnace,  since this state is now 70% green energy on its grid,  and rapidly adding more (I think we are rated the second windiest out of the fifty states).

And I generally dislike forms of energy that can leak in catastrophic ways, both in the household and in the field.  Very few die in their sleep breathing electrons.

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33 minutes ago, TheVat said:

Very few die in their sleep breathing electrons.

Disagree. We all breathe electrons.  😊

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18 hours ago, TheVat said:

I live in South Dakota,  which has bitter winters with regular blasts of Arctic air,  so heat pumps still seem problematic here.  I doubt the external air has much available heat at minus 20 F. (-29 C.)

And yet they are popular in Scandinavia.

18 hours ago, TheVat said:

And I generally dislike forms of energy that can leak in catastrophic ways, both in the household and in the field.  Very few die in their sleep breathing electrons.

I have no idea what you mean by this ?

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Studio -- the latter just a wee joke.   As in,  gas can leak from pipes or from flues,  but flowing electrons don't generally leak from wires and fill your bedroom or ignite.   Was just a way of nodding to the safety factor for non-combustion sources.

If heatpumps are viable in Scandinavia, that is encouraging.  I will look into that.

The principal objection you hear around here is that heatpump air is not as hot as furnace air,  so you don't have the delicious fountain of hot air coming from the grates.   This is part of the psychological aspect of comfort,  I suppose.

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1 hour ago, TheVat said:

If heatpumps are viable in Scandinavia, that is encouraging.  I will look into that.

Most of it is subsidised, or compulsory under certain conditions, so it's not a free market. And the vast majority is ground source not air source. The only big air source market is used extracting heat from exhaust air of buildings, not outdoor air, which is pretty cold in winter.

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Out of interest here is an example calculation I was recently sent for a much larger heat pump for a commercial building installation.

Quote

I'm going to suggest that there's a quick and cheap way to find out a building's actual peak heat load, using weekly or monthly consumption data and corresponding degree-day figures. Indeed, for someone who already operates an energy monitoring and targeting system the job is already almost done because they will have a regression model for each building relating consumption to degree days.

To show how it works let's imagine a building which has a fixed weekly consumption of 2,000 kWh per month and variable consumption of 180 kWh per degree day. Taking its base-load consumption first, as there are 730 hours in an average month, the fixed consumption equates to an average continuous power of 2,000/730 = 2.74 kW. Regarding the variable component of demand, 180 kWh per degree day is 180/24 = 7.5 kWh per degree hour, which is the same as  7.5 kW per degree (of temperature difference between outside and the building's balance point). So suppose we take our design coldest day as being, say, 17C below the balance point. Average input fuel power requirement on that day will be 2.74 + (7.5 x 17) = 130 kW. Finally we'd need to make an assumption about the existing system's efficiency to turn that peak input power into peak heat output of 130 x (say) 80% = 104 kW.

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