Energy price rises and price cap discussion.

[HSTEd]

"Fast as possible" needs some clarification in terms of actual reality in the number of years this aspiration will actually take.

It is true that nothing can help this winter, but that's the reality of where we are. You can't undo 40 years of energy policy in a few months.

The problem is the resources that will be squandered denying reality for a few months are the resources that are needed to prevent this in the future.

Do you really think the politicians pursuing the massive subsidy plan will ever let the subsidies cease? It's 60bn a year for the forseable future.

 

[DelayRepay]

I've always found "30 at 30" not to properly clean clothes. It gets visible muck out, but e.g. sweat is still there.

If using a low temperature, you need a longer cycle. But that's fine, because agitating clothes every 5-10 seconds or so isn't hugely energy-heavy.

I think it depends on the make of washing machine, and what each setting actually does.

I find "30 at 30" doesn't work well either. But my eco setting is "30 for about 2.5 hours" which works fine for most things. Actual stains seem to benefit from a higher temperature, but general day to day laundry is fine. Actually, I don't know if the 'eco' setting is about using less power or less water, or a combination of both.

I have a quick wash button but I think that's designed for when you're in a hurry, rather than when you want to save power or water.

I think the main point is that unless you put everything on a boil wash, then which cycle you pick won't actually make more than a penny or two's difference to the cost in terms of power or water. Most people could probably save more by just not washing until things actually need it, and they have a full load.

 

[Trainbike46]

I think it depends on the make of washing machine, and what each setting actually does.

I find "30 at 30" doesn't work well either. But my eco setting is "30 for about 2.5 hours" which works fine for most things. Actual stains seem to benefit from a higher temperature, but general day to day laundry is fine. Actually, I don't know if the 'eco' setting is about using less power or less water, or a combination of both.

It's both. As most of the energy goes into heating the water, having less water to heat saves energy as well.

I have a quick wash button but I think that's designed for when you're in a hurry, rather than when you want to save power or water.

I think the main point is that unless you put everything on a boil wash, then which cycle you pick won't actually make more than a penny or two's difference to the cost in terms of power or water. Most people could probably save more by just not washing until things actually need it, and they have a full load.

The difference between a 60 C and a 30 C wash is quite significant. But yeah, the savings by washing fewer loads are probably bigger.

 

[Bletchleyite]

I find "30 at 30" doesn't work well either. But my eco setting is "30 for about 2.5 hours" which works fine for most things. Actual stains seem to benefit from a higher temperature, but general day to day laundry is fine. Actually, I don't know if the 'eco' setting is about using less power or less water, or a combination of both.

I generally do 40 for about 2.5 hours, by picking the 60 degree cycle but knocking the temperature down. The reason I started doing that was that the built in 40 cycle (about an hour and a half) doesn't get all the detergent out and it was causing skin irritation.

I think the main point is that unless you put everything on a boil wash, then which cycle you pick won't actually make more than a penny or two's difference to the cost in terms of power or water. Most people could probably save more by just not washing until things actually need it, and they have a full load.

Yes, agreed. Changing the temperature will have more effect than the cycle. I'll have to try 20 and see how well that works, I suspect just fine.

== Doublepost prevention - post automatically merged: 15 Aug 2022 ==

It's both. As most of the energy goes into heating the water, having less water to heat saves energy as well.

A longer cycle doesn't necessarily take more water. It can agitate in the same water for longer. You might have a miniscule extra sum for lost heat.

 

[Trainbike46]

Ultimately the political classes only plan is to blow tens of billions in a few months denying reality with regards energy prices.

The reality is that subsidising energy prices is going to consume more money than the Society can spare very very quickly.
Insulation probably isn't worth it given the restrictions on our available manpower and equipment pool and its limited effectiveness. (Even the pro insulation people talking about 10% energy savings most of the time)

The potential for savings from insulation is large, but vary a lot on what insulation is already present. In addition, savings are usually quoted for a single measure, such as insulating the roof. If you were to insulate the roof, walls and floor, the savings do really add up.

In some other areas there is a push for "zero energy on the meter" homes, where with a combination of insulation, heat pumps and solar panels the annual energy consumption of the home comes to zero! insulation is key to get us out of this current mess

The only way to get around this is to go and build generating plant as fast as possible so that this mess can never repeat itself.

Turns out they're already building in the southwest, and are due to start in Suffolk soon! That is, on top of the various wind projects that are in the pipeline.

== Doublepost prevention - post automatically merged: 15 Aug 2022 ==

A longer cycle doesn't necessarily take more water. It can agitate in the same water for longer. You might have a miniscule extra sum for lost heat.

Of course a longer cycle doesn't take more water. I was replying to what the idea behind the ECO cycles was, and that is both less water and less energy, and these work together as less water means less energy needed for heating

== Doublepost prevention - post automatically merged: 15 Aug 2022 ==

Yes, agreed. Changing the temperature will have more effect than the cycle. I'll have to try 20 and see how well that works, I suspect just fine.

Can you report back here when you know? I should probably try, but as my washing machine doesn't have a 20 C option, it would be the cold option

 

[HSTEd]

The potential for savings from insulation is large, but vary a lot on what insulation is already present. In addition, savings are usually quoted for a single measure, such as insulating the roof. If you were to insulate the roof, walls and floor, the savings do really add up.

In some other areas there is a push for "zero energy on the meter" homes, where with a combination of insulation, heat pumps and solar panels the annual energy consumption of the home comes to zero! insulation is key to get us out of this current mess

The problem is doing these things requires industrial output and personnel to be diverted to them.

Many of these insulation tasks are enormously disruptive and laborious, there is already a crippling shortage of labourers for such back breaking labour.

Every worker we have doing this is one that can't be sitting on a production line pumping out wind turbines, nuclear reactor parts or similar.
The staff requirements proposed for these retrofit programmes are enormous.

 

[najaB]

The headlong rush to close coal burners without having an alternative in place first. The reliance on gas from, shall we say, countries with dubious practices.

Gas was the alternative that was in place.

Many of these insulation tasks are enormously disruptive and laborious, there is already a crippling shortage of labourers for such back breaking labour.

Every worker we have doing this is one that can't be sitting on a production line pumping out wind turbines, nuclear reactor parts or similar.

The thing there is that nuclear plant assembly is a high-skill task as compared to putting in loft insulation, so it's not like they're pulling from the same labour pool.

 

[trebor79]

Other than the insulting use of the word 'morons' to describe people who just don't have accurate information to hand, it would be useful if you could expand on this point.

If I return to an unheated house after a few days away then all of the house is cold - the walls, the furniture, the furnishings and the contents. As I put heat into the house some of it, by the laws of physics/nature, is going to be absorbed by those items. You can't heat just an air bubble surrounding your person - although I do note the phrase 'heat the body not the house'. How many hours per day would a house need to be occupied before it actually was beneficial to keep the whole fabric heated permanently or the other way round how long would the house need to be unnoccupied to make it worth losing the heat after the morning burn and warming it again upon return?

Where has all that heat fro the walls etc escaped to?
Once your house has cooled to ambient you lose no more heat. Keeping your house heated means you continually lose heat and burn fuel to replace it.
Here's an experiment. Go away for a week in winter and leave the heating on. See how much fuel you've used fro the day you go away to the day after you come back.
Now do the same again, but turn the heating off whilst you're away. You will find you've used far less fuel letting the house get cold and heating it back up again than keeping it hot.
Do you keep the oven turned on whilst you're not using it? Why not? Same principle.

 

[ainsworth74]

Gas was the alternative that was in place.

And presumably, at that time, the expectation was that the gas would be coming almost entirely from our own stocks in the North Sea?

Still though, the failure over the last thirty/forty years to build nuclear power plants is a nearly unforgiveable dereliction of duty. France showed the way to go back in the 1970s and it's disastrous that no only have other countries not followed their lead but have indeed gone backwards (see Germany and their closure of nuclear power stations for no good reason).

 

[Bletchleyite]

And presumably, at that time, the expectation was that the gas would be coming almost entirely from our own stocks in the North Sea?

Still though, the failure over the last thirty/forty years to build nuclear power plants is a nearly unforgiveable dereliction of duty. France showed the way to go back in the 1970s and it's disastrous that no only have other countries not followed their lead but have indeed gone backwards (see Germany and their closure of nuclear power stations for no good reason).

It happened in Germany due to Die Gruenen, I believe.

Green Parties, just like here, are a threat to decarbonisation because they oppose things that provide for a lower carbon future like nuclear power and HS2. I will never vote Green as a result.

"Zealot" parties are never good. Moderation is always the way in politics; an only-just-left-of-centre social democratic party with an eye on carbon and particulate emissions is the best way.

 

[Mogster]

The problem is doing these things requires industrial output and personnel to be diverted to them.

Many of these insulation tasks are enormously disruptive and laborious, there is already a crippling shortage of labourers for such back breaking labour.

Every worker we have doing this is one that can't be sitting on a production line pumping out wind turbines, nuclear reactor parts or similar.
The staff requirements proposed for these retrofit programmes are enormous.

These things aren’t suitable for every home either, particularly older properties. Every roof isn’t suitable for efficient solar and installing is very expensive, that’s the problem with the suggestion that solar should be installed on “every” new home.

I don’t see how you can’t force these changes on owners of existing properties. New properties can be designed with insulation, heat pumps, solar, low water use in mind but it will still add to the cost of the properties.

 

[Bletchleyite]

Many of these insulation tasks are enormously disruptive and laborious, there is already a crippling shortage of labourers for such back breaking labour.

Which is why DIY should be included in the funding, not just paying someone to do it. Loft insulation should, for example, be completely free.

 

[ainsworth74]

It happened in Germany due to Die Gruenen, I believe.

Green Parties, just like here, are a threat to decarbonisation because they oppose things that provide for a lower carbon future like nuclear power and HS2. I will never vote Green as a result.

"Zealot" parties are never good. Moderation is always the way in politics; an only-just-left-of-centre social democratic party with an eye on carbon and particulate emissions is the best way.

Yes sorry to be clear I was aware of it being due to the German Green Party (and parties like them) I just reject their arguments and so treat them as a whole as "having no good reason"

But yes exactly like you until Green Parties stop opposing things which are clearly required to provide a low carbon future and, in the case of nuclear, energy security (whilst seemingly ignoring things like Road Investment Strategy) would be unable to support them. Which is ironic as I'm otherwise probably a natural target for them but those are two bright red lines for me.

However I think we're probably heading off-topic here!

 

[Bletchleyite]

But yes exactly like you until Green Parties stop opposing things which are clearly required to provide a low carbon future and, in the case of nuclear, energy security (whilst seemingly ignoring things like Road Investment Strategy) would be unable to support them. Which is ironic as I'm otherwise probably a natural target for them but those are two bright red lines for me.

Same. I want to vote for a party that will tax fairly but appropriately and will build nuclear and renewable power, promote the transition to EVs (cars, buses and lorries), build a high speed rail network, invest in our existing railways and properly integrated electric bus services, and install German-standard electric rail transport in our big cities and tramways in our smaller ones, as well as promoting quality cycle infrastructure on the Dutch model, thereby providing a massive carrot to using cars less.

You'd think that'd be what a Green Party would do, but oh no.

 

[devon_metro]

Still though, the failure over the last thirty/forty years to build nuclear power plants is a nearly unforgiveable dereliction of duty. France showed the way to go back in the 1970s and it's disastrous that no only have other countries not followed their lead but have indeed gone backwards (see Germany and their closure of nuclear power stations for no good reason).

The French day ahead power price is an aveage of EUR500/MWh tomorrow, compared to the UK's at EUR450/MWh. France is having serious issues with its nuclear fleet, so it's not something you want to be too dependent on, though I agree it's useful baseload.

 

[JamesT]

The French day ahead power price is an aveage of EUR500/MWh tomorrow, compared to the UK's at EUR450/MWh. France is having serious issues with its nuclear fleet, so it's not something you want to be too dependent on, though I agree it's useful baseload.

It's been noticeable when I've looked at Gridwatch over the last few weeks the French interconnecter has been showing negative numbers, which I understand to mean us exporting to them. (It's showing postive as I type)

 

[AM9]

The problem is doing these things requires industrial output and personnel to be diverted to them.

Many of these insulation tasks are enormously disruptive and laborious, there is already a crippling shortage of labourers for such back breaking labour.

Every worker we have doing this is one that can't be sitting on a production line pumping out wind turbines, nuclear reactor parts or similar.
The staff requirements proposed for these retrofit programmes are enormous.

That's the short-term view, but every house that has sensible insulation installed is fixed for good so in effect has a slight benefit in lightening the load on the renewable energy equipment not yet built. It's not a zero sum game here, time taken out from wind turbines, to insulate houses, is a short interruption, but a long-term saving.
And that assumes that the same type of skilled labour is required for both house insulation and turbines, - it clearly isn't.

The same old lack of foresight again making the mess that it has already created even worse. To use an analogy, - who would rush to get a bugger pump to fill a storage tank that has a leak in preference to fixing the leak.

 

[HSTEd]

That's the short-term view, but every house that has sensible insulation installed is fixed for good so in effect has a slight benefit in lightening the load on the renewable energy equipment not yet built. It's not a zero sum game here, time taken out from wind turbines, to insulate houses, is a short interruption, but a long-term saving.
And that assumes that the same type of skilled labour is required for both house insulation and turbines, - it clearly isn't.

The same old lack of foresight again making the mess that it has already created even worse. To use an analogy, - who would rush to get a bugger pump to fill a storage tank that has a leak in preference to fixing the leak.

The savings from insulation versus building more generating plant would not be realised for decades, if ever.

Many generating units built today will have service lives of half a century or more, especially for things like tidal where the service lives are almost infinite.

Given that climate change will be over one way or another inside two decades (we will either have reached zero carbon or we are stuffed anyway), savings fifty years from now are comparably less important

And many items like domestic heat pumps will have strictly shorter service lives than generating plant and will never be favoured over more generating plant

 

[AM9]

The savings from insulation versus building more generating plant would not be realised for decades, if ever.

Many generating units built today will have service lives of half a century or more, especially for things like tidal where the service lives are almost infinite.

Given that climate change will be over one way or another inside two decades (we will either have reached zero carbon or we are stuffed anyway), savings fifty years from now are comparably less important

And many items like domestic heat pumps will have strictly shorter service lives than generating plant and will never be favoured over more generating plant

So perpetuate the same argument and never insulate anything other than new build. The savings from insulation manifest themselves within a year, - not the saving of the complete insulation cost, but a reduction onn the amount of energy required partially at least offsetting the rise in energy cost to the consumer. That flows down as a saving for the exchequer because as @Bletchleyite posts, the government should (and probably will have to) fund much of the costs of improving the UK's leaking homes. Even if all of our energy was 'recyclable' failing to address the leakage from domestic dwellings would still present a massive avoidable expense.
Somebody up thread objected to paying for other people's home improvements, - a typical self-centred argument in the insulation debate which the Conservative government seems to particularly warm* to, clearly not recognising that eventually we will all pay for the support both in energy/food that some of those in leaky homes will need, but it will also include yet another poverty-induced hit on the NHS.
* pun not intended

 

[DelayRepay]

And that assumes that the same type of skilled labour is required for both house insulation and turbines, - it clearly isn't.

Agree - the original argument is flawed. We can do both, and we need to do both.

We should start with the low hanging fruit - suitable new builds and suitable existing properties (regardless of ownership) where the owner is keen to have the work done. If I have better insulation in my private house, I benefit from lower bills. Everyone else benefits because I am taking less power from the grid.

Do I expect the government to fund improvements to my home? No, but it's unlikely I'll pay the full cost of the upfront improvements myself. This would require me to take out a loan and I don't know if I'll live here long enough to see a return of my capital through lower bills.

How I would do it have the work completed at very low cost to the home owner, but the government takes a share of the money saved through lower bills. This money would go back into the central fund to pay for the next lot of improvements. And if you had solar panels, the government rather than home owner should benefit from any surplus electricity.

And I agree with @Bletchleyite, if someone is able and willing to do the work themselves, the materials should be provided free of charge, along with some basic training/advice about what's needed and the best way to go about it. I imagine this approach would deal with a significant volume of loft insulation because some people would do their own house, then may help relatives to do theirs. Obviously this wouldn't work for more complex measures like installing solar panels.

In parallel, the government should be really pushing insulation of public buildings and local authority/housing association properties etc.

== Doublepost prevention - post automatically merged: 15 Aug 2022 ==

Somebody up thread objected to paying for other people's home improvements, - a typical self-centred argument in the insulation debate which the Conservative government seems to particularly warm* to, clearly not recognising that eventually we will all pay for the support both in energy/food that some of those in leaky homes will need, but it will also include yet another poverty-induced hit on the NHS.

The argument about paying to improve other people's homes is a bit like saying you shouldn't pay towards the cost of the education system because you don't have children, or you shouldn't pay towards the NHS because you're personally fit and healthy.

We need a change in mindset - yes insulation would improve my home, but it also improves the country as a whole by meaning less energy is being used. This, in theory, should lead to prices falling (or not rising as quickly) due to lower demand. Obviously one house won't make a difference, but tens of thousands of houses would. The Net Zero target is the government's, for the whole country, and widespread insulation will help them achieve it. If very cheap insulation was widely available then it wouldn't add to the value of my house because the next purchaser could simply have the works completed at a low cost to themselves.

 

[HSTEd]

And that assumes that the same type of skilled labour is required for both house insulation and turbines, - it clearly isn't.

Ultimately given the total lack of reserve capacity in either industry and the size of any construction programme for turbines requiring assembly line techniques - they do draw from the same labour pool.

The majority of labour involved in manufacturing turbines on this scale will involve a lot of people on assembly lines doing the same job over and over and over.
Probably a lot involving placing metal parts in stamping presses or similar. Not some hyper skilled engineering types.

The reality is that a significant insulation programme will require hundreds of thousands of labourers for years.
And we simply don't have hundreds of thousands of labourers!

We already having a crippling labour shortage.
The same amount can be achieved with a tiny fraction of the labour by building more generating plant - sure each labour hour might be somewhat more valuable in cash terms, but that's not the issue - the issue is our physical ability to make things.

I can find 50,000 people to work in a generating plant supply chain far more easily than I can find 500,000 insulation people.

So perpetuate the same argument and never insulate anything other than new build. The savings from insulation manifest themselves within a year, - not the saving of the complete insulation cost, but a reduction onn the amount of energy required partially at least offsetting the rise in energy cost to the consumer. That flows down as a saving for the exchequer because as @Bletchleyite posts, the government should (and probably will have to) fund much of the costs of improving the UK's leaking homes. Even if all of our energy was 'recyclable' failing to address the leakage from domestic dwellings would still present a massive avoidable expense.
Somebody up thread objected to paying for other people's home improvements, - a typical self-centred argument in the insulation debate which the Conservative government seems to particularly warm* to, clearly not recognising that eventually we will all pay for the support both in energy/food that some of those in leaky homes will need, but it will also include yet another poverty-induced hit on the NHS.
* pun not intended

We ultimately are far beyond money.
Money no longer matters in this context.

We are constrained by our physical ability to do things.

The estimates on insulation normally assume you can just expand the output of insulation programmes by one or even two orders of magnitude without increasing the unit cost - which is insanity in today's labour market.

 

[najaB]

France is having serious issues with its nuclear fleet, so it's not something you want to be too dependent on, though I agree it's useful baseload.

Though, that's specifically due to the fact that they pull their cooling water largely from rivers rather than the sea like we do. It has the advantage of less salt-water corrosion issues, but does mean that droughts are a real problem.

== Doublepost prevention - post automatically merged: 15 Aug 2022 ==

Ultimately given the total lack of reserve capacity in either industry and the size of any construction programme for turbines requiring assembly line techniques - they do draw from the same labour pool.

The majority of labour involved in manufacturing turbines on this scale will involve a lot of people on assembly lines doing the same job over and over and over.
Probably a lot involving placing metal parts in stamping presses or similar.

The reality is that a significant insulation programme will require hundreds of thousands of labourers for years.
And we simply don't have hundreds of thousands of labourers!

We already having a crippling labour shortage.

That kind of job is what automation is for.

 

[HSTEd]

That kind of job is what automation is for.

Automating insulation retrofit sounds like a rather huge engineering challenge!

Wind turbine manufacture or even nuclear reactor manufacturing... not so much.

 

[AM9]

Automating insulation retrofit sounds like a rather huge engineering challenge!

Wind turbine manufacture or even nuclear reactor manufacturing... not so much.

I think the claim that turbine manufacture would require so much of the UK workforce was the target of that comment. As far as insulation installation goes, the DIY workforce could easily be motivated as @DelayRepay and Bletchleyite has suggested. Let's face it, the 'Insulate Britain' protests tweaked the Government's conscience last year, yet they decided to refuse to talk to them and bury the real issue in the interest of not inconveniencing motorists. OK, it's time to grow up now and bite the bullet.

 

[DelayRepay]

I think the claim that turbine manufacture would require so much of the UK workforce was the target of that comment. As far as insulation installation goes, the DIY workforce could easily be motivated as @DelayRepay and Bletchleyite has suggested. Let's face it, the 'Insulate Britain' protests tweaked the Government's conscience last year, yet they decided to refuse to talk to them and bury the real issue in the interest of not inconveniencing motorists. OK, it's time to grow up now and bite the bullet.

The other flaw in the argument is the location of these turbine manufacturing jobs. Unless every town and city hosts a turbine factory, they simply won't be relevant jobs for the majority of the population. Whereas every town and city does have plenty of buildings that could be insulated.

 

[devon_metro]

Though, that's specifically due to the fact that they pull their cooling water largely from rivers rather than the sea like we do. It has the advantage of less salt-water corrosion issues, but does mean that droughts are a real problem.

French nuclear availabity has been pretty low for several months now due to reliability issues and an ageing fleet. The lack of cooling water is just another recent problem. I believe French nuclear is operating at somewhere around 50%, which is going to be an issue when it comes to winter. The UK typically imports up to 3GW (and in theory 4GW this winter now the channel tunnel interconnector is operational) from France.

 

[Baxenden Bank]

Can you report back here when you know? I should probably try, but as my washing machine doesn't have a 20 C option, it would be the cold option

I can part answer:
60 degree mixed wash programme, 1h 30m, 1.3kWh, 43p at daytime rates.
40 degree mixed wash programme, 1h 0, 0.8kWh, 26p.
So 30 minutes extra heating the water to a higher temperature and 17p more per use.
Those are the only two programmes, out of the many available, that I use.

For a while I had a 'broken' machine which failed to heat the water at all but otherwise worked fine. The clothes washed fine too as far as I could tell but after a few months towels started getting a bit smelly. I suspect that it is to do with the ingredients of liquid soap rather than the washing cycle. I determine this because I have been recycling bath water for other purposes and the buckets collect a gloopy slimy residue with the same smell.

As to temperature, if I need to heat water (immersion) at at least 50 degrees to kill any bugs, surely something similar applies to laundry? All those shirts you sneezed into the elbow of.

Also, as @Bletchleyite refers to leaving detergent on clothes after a shorter wash, and someone referred to how ECO and low temperature washes take advantage of modern detergents, how do these work on non-bio powders - for us softies with sensitive skin?

== Doublepost prevention - post automatically merged: 15 Aug 2022 ==

Where has all that heat fro the walls etc escaped to?
Once your house has cooled to ambient you lose no more heat. Keeping your house heated means you continually lose heat and burn fuel to replace it.
Here's an experiment. Go away for a week in winter and leave the heating on. See how much fuel you've used fro the day you go away to the day after you come back.
Now do the same again, but turn the heating off whilst you're away. You will find you've used far less fuel letting the house get cold and heating it back up again than keeping it hot.
Do you keep the oven turned on whilst you're not using it? Why not? Same principle.

Some actual science or research findings would be useful.

Over a period of several days yes, the house cools to ambient temperature. But does that also apply to going to work, say absent for 10 hours. Or a part day out shopping. Or an hours trip to the supermarket?

 

[najaB]

Automating insulation retrofit sounds like a rather huge engineering challenge!

Wind turbine manufacture or even nuclear reactor manufacturing... not so much.

Exactly. The parts of manufacturing that are only high-skill because of the level of precision required are perfect candidates for automation.

As to temperature, if I need to heat water (immersion) at at least 50 degrees to kill any bugs, surely something similar applies to laundry? All those shirts you sneezed into the elbow of.

The main issue there is that when you shower you end up breathing in water droplets and/or get them into your eyes (or other sensitive areas) so there's a direct path for the bugs to get into nice place to reproduce. This is much less of an issue with clothes since you usually dry them before wearing, and they also represent less of an effective path for bugs to get into the wet/warm areas of the body.

 

[Adoarable]

Some actual science or research findings would be useful.

Over a period of several days yes, the house cools to ambient temperature. But does that also apply to going to work, say absent for 10 hours. Or a part day out shopping. Or an hours trip to the supermarket?

Some GCSE science.
Newton's law of cooling: the rate of heat loss of a body is directly proportional to the difference in temperatures between the body and its environment.
Law of conservation of energy: energy can neither be created nor destroyed.

Assume your thermostat and heating system is perfect, i.e. when it's set it always delivers the exact right amount of heat required to keep the house at a constant temperature.

Therefore (and by the law of conservation of energy), the energy used by the heating system is exactly equal to the energy that is lost from the house as heat.

Let's declare some variables:
- To = outside temperature
- Tt = thermostat temperature
- Th = house temperature

Say you go out for an hour and you don't know whether to keep the heating on or not.
Option 1: You keep the heating on. By Newton's law of cooling, the amount of energy used is k * (1 hour) * (Tt - To), where k is some constant.
Option 2: You turn the heating off. Your house cools down as it loses heat. For argument's sake, let's say you've set a timer or used an app to turn the heating back on 10 minutes before you get home so it's toasty when you get in. Here the heat loss and hence amount of energy used is k times the integral of (Th - To) over the 1-hour period.

Since at all times To <= Th <= Tt, it's pretty clear that Option 2 uses less energy than Option 1.

 

[trebor79]

Some actual science or research findings would be useful.

Over a period of several days yes, the house cools to ambient temperature. But does that also apply to going to work, say absent for 10 hours. Or a part day out shopping. Or an hours trip to the supermarket?

Yes, it's always cheaper to turn off the heating if the house in unoccupied. Same reason you always turn off the oven when you aren't cooking anything, even if you're going to cook something later.
@Adoarable has explained eloquently.
Also, consider these two charts, which visualise what has been said. Heat loss is equivalent to k * the shaded area. The shaded area is larger in case 1, therefore more heat has been lost in case 1, therefore you've used more fuel. QED. It's really basic thermodynamics and not at all difficult to understand, which is why I felt justified to describe people who believe the counter-factual in the way I did.

Now, it might be more comfortable or preferable for other reasons to keep the house warm, but you only keep the walls etc warm by continually replacing the heat that they are dissipating to the atmosphere. To pretend or try to convince that it uses less fuel to do this than not keeping the house warm when unoccupied is anti-science, and, yes, moronic.