Energy bill increases

[rogerzilla]

Air source heat pump CoP is 2.5-2.8 in the UK. Let's be generous and say 2.8. So to get 1 kWh of heat, you put in 0.35kWh of electricity. Great. But electricity is 5x the cost of gas per kWh, so 5 x 0.35 = 1.75x the cost. Correct for the efficiency of a gas boiler (say 80%) and you get 1.4x the cost. But you will need to use resistance top-up heating at some times, so 1.5x is a pretty good estimate. I'm ignoring the problem that you can't let the house go cold and just heat it back up when you're in, which is much cheaper than leaving the heating on all the time (a cool house loses residual heat more slowly). Allow for that, and someone who is out all weekdays might see bills triple.

Ground source heat pumps are quite a bit better and might just about break even on cost, but you need a massive garden or a deep borehole.

 

[PaulSB]

I look forward to the day someone tries to install a heat pump in our back yard. 😄 Not a hope in hell!!! 😄

Alternatively get permission from the council to install one on the front of the cottage whuch is subject to an Article 4 direction.

The whole idea is a joke.

 

[mjr]

Air source heat pump CoP is 2.5-2.8 in the UK. Let's be generous and say 2.8.

There's the first mistake. Even in the depths of January, with a system with a known fault awaiting a spare part, I'm getting 2.9. On a warm winter's day, it still does 3.8. No way is the long-term average with a current unit going to be as low as 2.8 unless there is a serious fault or an installation error.

But electricity is 5x the cost of gas per kWh,

And that's the second mistake. Gas is going up to 7p/kWh, electric 28p/kWh. 28 is not 5x7...

But you will need to use resistance top-up heating at some times,

Once every couple of weeks on a legionella-preventing cycle. Not enough to move the multiplier noticeably.

I'm ignoring the problem that you can't let the house go cold and just heat it back up when you're in, which is much cheaper than leaving the heating on all the time (a cool house loses residual heat more slowly). Allow for that, and someone who is out all weekdays might see bills triple.

Where is this BS coming from? You just tell the heating controller to let the temperature dip during the day and warm it back up 2h or so before you expect to be home. I agree you probably don't want to leave it low until you get in, else you'll have to drive the heatpump at maximum which, yes, is more expensive, (the quoted efficiency is taken between mid and max), but these systems mostly come with decent remote controls and apps and APIs and stuff so it's not a problem once you have it set up.

 

[rogerzilla]

My electricity is 4.96x the cost of gas per kWh, on a very ordinary Eon capped tariff so no, it's not a mistake. And the CoP came from a green energy site where they are trying to get people to change.

This is terrifying: https://myhomefarm.co.uk/potential-air-source-heat-pump-running-cost-issue

And they have solar PV to help!

 

[MrGrumpy]

It’s scary ! Unless you have very well insulated home , your fighting a loosing battle with the leccy cost !

 

[mjr]

My electricity is 4.96x the cost of gas per kWh, on a very ordinary Eon capped tariff so no, it's not a mistake.

And we already know it won't be in 8 weeks time and in the medium term gas is going to get relatively more expensive as it runs out.

And the CoP came from a green energy site where they are trying to get people to change.

Doesn't matter where it came from, it's much too low. Listed annual averages are high 3s. A minor faulty system in winter does better than 2.8.

This is terrifying: https://myhomefarm.co.uk/potential-air-source-heat-pump-running-cost-issue

And they have solar PV to help!

Mars has websites to fund, as well as a minor brand heat pump system in an old stone farmhouse. He is right on some things, such as the climate change levy, but he goes a bit hot and cold (contrary to the myth that heat pumps have to be hot all the time ).

Edit to add: this suggests something is very wrong with his system: "Lower room temperatures don’t work in dropping consumption, in our experience, in our case because the pump is still heating flow rate temperatures to 45C irrespective." Lowering room temperatures should drop consumption because less heat is required, so it may be heating water to 45 the same but it should be from a higher starting point as it lost less heat on its way around the radiators, so cost less. So firstly, it sounds like his system may be dumping heat if any radiators are turned down. And secondly, a constant radiator flow temperature is inefficient and unusual, with most air source systems (and some gas modulating boilers now, especially German-made controllers) varying the temperature inversely with outdoor temperature. In short, there is no way that a system outputting less heat shouldn't consume less than if it outputs more in the same conditions, unless it is very broken.

 

[PaulSB]

I'm interested to learn about heat pumps as other than these extract heat from the air or ground I know nothing. I've understood installation of gas boilers in new builds will be banned from 2025 but this does not mean replacing existing gas boilers will be banned. I wonder how a heat pump would work in my circumstances.

Our stone built mid-terrace cottage is 177 years old. All windows are double glazed, we have front and rear porches and the outside doors have been replaced with properly fitting ones. There is insulation in the floor space between the first floor and attic room and the roof is insulated. The property is in a conservation area and subject to an Article 4 Direction. To fit an ASHP in the backyard would entail moving water, drainage, foul water and gas pipes. To improve insulation internally would mean a huge investment. Any form of exterior insulation, solar panels etc. would not be possible due to the Article 4 Direction.

It seems to me we are far from unique, there will be millions of properties in which anything other than gas fired heating is either impossible or financially unattainable. The idea of banning gas boiler installation in the +/- 150,000 new builds per annum will have no serious impact in the short term. Surely it would make more sense to invest in supplying some form of natural gas/hydrogen mixture to all households on the basis hydrogen produces no pollutants. I've no idea of if this is technically possible or even safe?

 

[mjr]

The property is in a conservation area and subject to an Article 4 Direction. To fit an ASHP in the backyard would entail moving water, drainage, foul water and gas pipes. To improve insulation internally would mean a huge investment. Any form of exterior insulation, solar panels etc. would not be possible due to the Article 4 Direction.

I agree with your earlier post: "not a hope in hell" with the current equipment, as far as I know. Yours doesn't seem like the sort of place where you can bang a small hole in a wall and run a new "drainpipe" down to a box in the yard, which is what we've got here.

Insulation isn't really much more relevant to heat pumps than any other form of heating. I think it gets linked to heat pumps because the government switchover grants only pay out if you have insulated up to a pretty basic modern-home standard anyway, with loft and wall insulation, so that they aren't paying for bigger heat pumps than really needed... but that does pose challenges for some older buildings.

But something's going to have to change before the gas starts to die out, else such buildings will become so expensive to heat that they ruin their occupiers, or they will be abandoned and left to become a ruin. I suspect properties like yours will probably be among the last to switchover. It would be fascinating to know how many properties are in each category, like "ready to switchover at next boiler replacement", "small works required", "major works required", "HTF?" and so on.

[...] Surely it would make more sense to invest in supplying some form of natural gas/hydrogen mixture to all households on the basis hydrogen produces no pollutants. I've no idea of if this is technically possible or even safe?

Safe and possible as far as I can tell, but it seems to make little sense yet unless you are near certain chemical works because so much hydrogen production uses fossil fuels, often including natural gas, plus it's a lower-density fuel... Still, smart people are testing whether hydrogen could be added to the gas mains, when and how. Even if it turns out to be environmentally bonkers, I don't expect the gas industry in this country to shut down without a fight. https://www.rechargenews.com/energy...end-in-public-natural-gas-network/2-1-1045075

 

[oldwheels]

The real pity is all UK governments failed to use the financial bounty offered by natural gas to invest in UK infrastructure meaning we simply squandered the fuel for decades.

I was completely unaware of what other countries, Norway for example, were doing but I think one could expect one's leaders to have some small inkling.

Burning gas is not the answer.

The SNP have been banging on about Norway and the Oil Fund they built up for a long time now but the money here was used for infrastructure much of it in London. Don't think that is veering too far into politics but I will not continue.

 

[oldwheels]

Air source heat pump CoP is 2.5-2.8 in the UK. Let's be generous and say 2.8. So to get 1 kWh of heat, you put in 0.35kWh of electricity. Great. But electricity is 5x the cost of gas per kWh, so 5 x 0.35 = 1.75x the cost. Correct for the efficiency of a gas boiler (say 80%) and you get 1.4x the cost. But you will need to use resistance top-up heating at some times, so 1.5x is a pretty good estimate. I'm ignoring the problem that you can't let the house go cold and just heat it back up when you're in, which is much cheaper than leaving the heating on all the time (a cool house loses residual heat more slowly). Allow for that, and someone who is out all weekdays might see bills triple.

Ground source heat pumps are quite a bit better and might just about break even on cost, but you need a massive garden or a deep borehole.

My son has installed an air source heat pump for a 20 year old house. There was a lot of work involved but so far the electricity bills are about 25% of previous storage heaters. I have been there recently in cold weather and can confirm the house is comfortable. Gas is not an option.

 

[mjr]

As we face the probability if boiler replacement in the next few years (its over 25 years old) air source heat pumps are definately OFF the consideration list for several reasons .
We are fresh air lovers, its 6c outside, its been 9c generally today but our heating hasnt been on at all today , windows have been open as well. When we do heat the house, it starts from very cold (maybe 14 or 15c inside) air source has no chance in those circumstances.

Presumably even the gas boiler costs a bomb to heat it up from 14? But indeed, an air source heat pump with 40ish degree radiators will take longer to heat it up than a gas boiler with 70ish degree ones, and I understand the current air source heat pumps with high-temperature radiators cost more to run than gas.

No way can i live in an airless stuffy, windows closed house.

So change the air in it. Heat-recovery ventilators are available. And if you want a breeze, then go outside and leave the house warm for later.

My son (gas engineer) has studied them a fair but. A very very well insulated house is a pre requisite.

Only a pre-requisite if you want the grants. May I suggest that gas engineers have a tiny bit of a conflict of interest?

we fail because we like fresh air. Supplementary heating (underfloor or similar) may well be needed?

It sounds like you fail because you open the windows and then heat a cold house quickly. Not sure what difference supplementary or underfloor heating would make: if you open the windows, it'll still get cold and cost lots to reheat quickly.

Supplementary water heating may well be needed. As a bath lover, it would be a neccessity.

It's usually installed (just like most fossil-heated tanks have an immersion for emergencies), but unless you have your baths hotter than 55°c (hot enough to cause third-degree burns in 30 seconds or less: the NHS recommends 46°c max), it wouldn't be used except for occasional legionnaires-killing and when outside temperature falls below -10°c for a prolonged period of time. If you have solar PV or solar thermal, you might choose to have supplementary water heating to save money.

Unless you hyper spec the system, with all the cost involved, its simply not going to work for people like us....and perhaps many others

It might, or it might not, but if all the above myths and legends were true, it wouldn't work for anyone, definitely not somewhere between 15 and 40 million and increasing across Europe. There's so many installed in Norway that oil heating was banned in 2020... but the UK lags behind most of Europe, with fewer than 10% of France's heat pumps, with these odd zombie myths stumbling onwards.

 

[fossyant]

My son has installed an air source heat pump for a 20 year old house. There was a lot of work involved but so far the electricity bills are about 25% of previous storage heaters. I have been there recently in cold weather and can confirm the house is comfortable. Gas is not an option.

Probably much better than storage heaters, but I doubt they would out perform an energy efficient gas boiler for cost of fuel though.

 

[Ming the Merciless]

I’ve been looking at the heat loss in the house between when the heating goes off and next comes on. I think we can shorten the time the heating may be on, plus maybe drop temp it aims at by 0.5C, without affecting our comfort. I’ll have a play with settings tomorrow.

Theres also some TRV radiator valves which don’t seem to switching certain radiators off (in rooms rarely occupied) properly. I’ll look at that as well.

 

[oldwheels]

Probably much better than storage heaters, but I doubt they would out perform an energy efficient gas boiler for cost of fuel though.

No mains gas available and possibly lower maintenance.

 

[iluvmybike]

Just had an email from Octopus re our fixed rate tariff ending - unlucky timing for us. We currently pay £88 per month for gas & electricity - our choice when the deal ends next month is to move onto a new 12mth fixed tariff at a mere £212 per month; move to their Loyalty (!!!) tariff at £189 per month or move onto the standard variable tariff at £107 per month. However, the SVT amount quoted is BEFORE the rise in April so its a bit of a red herring which is naughty and of course if cap goes up again it will rise even further. However, I think they are 'encouraging' folk to move onto the SVT by making the Fixed tariffs super expensive - this suggest to me that they think the market price is going to rise again. But they have you over barrel - a very quick trawl around comparsion sites shows it dreadful whatever you do. Some folk are really going to struggle with the horrendous price hikes