Use your car as a battery?

[JamesPa]

7 hours ago, joe90 said:

Which is why grants are available to help some make the changes they would like to make, yes I agree there are those that can’t make those changes but I believe the old ways (burning stuff and lack of insulation) will become a monetary burden so change is financially beneficial. This will never happen overnight but things are changing and for the better I believe.

For example I still drive a diesel car and is fairly economical but the cost of a new EV is beyond me and the scrapping of a serviceable car has hidden costs, yes I will change at some point when things move on (but being a “petrol head” I hope a clean ICE fuel can be found 🤣)

More or less all agreed.

 

My main point is that there are a large number of people who wont (not cant) make any change that causes (or which they perceive may cause) them personal inconvenience or cost, even if it benefits society at large or their children/grandchildren.  Putting it bluntly, they don't care about (or can't see) anything beyond their own small world as it is today.  They are egged-on by the the fossil fuel industry, the Daily Mail and the Daily Telegraph, GB News, Donald Trump, several British politicians (including but not limited to the Honourable member for the eighteenth century and his cronies), and the other people and organs of those who benefit from the status quo, don't understand or care to understand the science, and who are prepared to tell lies or half-truths to advance their own cause.  

 

However like you I am optimistic and believe things are changing.  I don't yet have an electric car but it wont be long.  I too want to wait until there is a natural replacement point; my annual mileage is about 5000 per year so it is probably environmentally more friendly to run my diesel car until it is a few years older anyway.  But I definitely will NOT be buying another fossil fuel car, as well as being environmentally more friendly electric cars are just better in many ways (arguably every way except range) than ICE cars  - simpler, faster acceleration, you charge them up at home so leave every day with a full tank, and you will eventually be able to use them to optimise your electricity bills.  Nor do I yet have a heat pump That's not for the want of trying, I have not got one solely because of my LPA, which (even though it has formally declared a climate emergency) is obstructing every attempt, has its head in the sand, and believes that insisting on a noise level of 25dBA at the most affected assessment point makes sense.  Eventually I will win this battle of course, its just taking more time and stress than I had hoped or even expected!

 

 

Edited February 22 by JamesPa

[Roger440]

13 hours ago, Dillsue said:

There's grid scale battery storage being rolled across the country to store renewables and help with the peak demand so you're already funding that through taxes and levies on your energy bills. Battery production has massive environmental impact so its ridiculous for the first world to have thousands of EV batteries sat doing nothing for most of the time when they could be productively utilised to reduce the amount of dedicated battery storage being installed.

 

It's not your power. If you read the link in the first post Octopus are going to charge your battery for free and take back SOME of it at peak times. Net result is you get some free energy in return for helping society keep the lights on.

 

If you are wanting a grid connection then why the obvious objection to helping society run a serviceable supply?

 

It IS my power if i generate it. To do so requires considerable investment. By me.

 

I have no desire to assist octopus, a company who have, behind closed doors and publically, lobbied and sought to distort the energy market to increase their sales and hence profits by increasing costs to customers who may not use them. Morally, im afraid that doesnt sit well with me. If you are OK with that, good for you.

 

Im happy to help society. But thats not who is being helped. The beneficiaries will be the power companies and government. Both corrupt. (have they changed how pricing including renewables is dealt with? No? Thats right. Got to keep the profits up.) With the government being the biggest threat to my way of life, livelihood and well being. Far more so than any risks that climate change may represent. If they had the citizens best interests at heart, that would be different, but they dont.

[Roger440]

2 hours ago, JamesPa said:

More or less all agreed.

 

My main point is that there are a large number of people who wont (not cant) make any change that causes (or which they perceive may cause) them personal inconvenience or cost, even if it benefits society at large or their children/grandchildren.  Putting it bluntly, they don't care about (or can't see) anything beyond their own small world as it is today.  They are egged-on by the the fossil fuel industry, the Daily Mail and the Daily Telegraph, GB News, Donald Trump, several British politicians (including but not limited to the Honourable member for the eighteenth century and his cronies), and the other people and organs of those who benefit from the status quo, don't understand or care to understand the science, and who are prepared to tell lies or half-truths to advance their own cause.  

 

However like you I am optimistic and believe things are changing.  I don't yet have an electric car but it wont be long.  I too want to wait until there is a natural replacement point; my annual mileage is about 5000 per year so it is probably environmentally more friendly to run my diesel car until it is a few years older anyway.  But I definitely will NOT be buying another fossil fuel car, as well as being environmentally more friendly electric cars are just better in many ways (arguably every way except range) than ICE cars  - simpler, faster acceleration, you charge them up at home so leave every day with a full tank, and you will eventually be able to use them to optimise your electricity bills.  Nor do I yet have a heat pump That's not for the want of trying, I have not got one solely because of my LPA, which (even though it has formally declared a climate emergency) is obstructing every attempt, has its head in the sand, and believes that insisting on a noise level of 25dBA at the most affected assessment point makes sense.  Eventually I will win this battle of course, its just taking more time and stress than I had hoped or even expected!

 

 

 

Do you not think your post is somewhat hypocritical?

 

You have decided the reasons that "other" people (who you know almost nothing about, or their circumstances)  are not spending their hard earned on your favoured technologies, whilst at the same time not having adopted any of them yourself and in the case of the car, justifying to (yourself?) why you dont need to.

 

As ive posted before, financially, insulation, ASHP or electric car, simply dont stack up finanicially. If you are fortunate enough that you dont need to consider if something makes economic sense and can press on anyway, then thats excellent for you. But dont presume that everyone else is in the same position. Nor, that even if it does stack up, that they can afford the very significant up front costs that come with all of those things i mention.

 

 

[joe90]

2 minutes ago, Roger440 said:

As ive posted before, financially, insulation, ASHP or electric car, simply dont stack up finanicially.

Really, well apart from the EV I invested in insulation to reduce my ongoing costs and the ASHP did an excellent job of delivering with a decent COP and all way cheaper to run than my previous house. Anyway it’s not only about finance IMO, It's about comfort which I achieved in spades!

[joe90]

7 minutes ago, Roger440 said:

can afford the very significant up front costs that come with all of those things i mention.

The additional costs of insulation in my build were minimal and my ASHP about the same as a gas boiler (if I had access to mains gas).

[Roger440]

14 minutes ago, joe90 said:

Really, well apart from the EV I invested in insulation to reduce my ongoing costs and the ASHP did an excellent job of delivering with a decent COP and all way cheaper to run than my previous house. Anyway it’s not only about finance IMO, It's about comfort which I achieved in spades!

 

I posted before, but to properly insulate my house, even doing it myself, is circa £30-40K.

 

That just makes no economic sense. I (likely) wont live long enough (20 years) to break even with the reduced fuel costs. Plus i need to have that to spend, up front, in one hit.

 

New build is an entirely different proposition.

Edited February 22 by Roger440

[Roger440]

9 minutes ago, joe90 said:

The additional costs of insulation in my build were minimal and my ASHP about the same as a gas boiler (if I had access to mains gas).

 

See previous post. Im not talking new build. Wish i was, because id have achieved building my own house. Sadly that dream has long since been abandoned and evaporated.

 

Hats of to those, like yoursef that made it happen.

[joe90]

6 minutes ago, Roger440 said:

New build is an entirely different proposition.

Very true, hence my comments on the listed building thread about affordable EWI on poorly insulated homes being a small step in the right direction.

[JamesPa]

10 hours ago, Roger440 said:

Do you not think your post is somewhat hypocritical?

 

You have decided the reasons that "other" people (who you know almost nothing about, or their circumstances)  are not spending their hard earned on your favoured technologies, whilst at the same time not having adopted any of them yourself and in the case of the car, justifying to (yourself?) why you dont need to.

 

As ive posted before, financially, insulation, ASHP or electric car, simply dont stack up finanicially. If you are fortunate enough that you dont need to consider if something makes economic sense and can press on anyway, then thats excellent for you. But dont presume that everyone else is in the same position. Nor, that even if it does stack up, that they can afford the very significant up front costs that come with all of those things i mention.

No I don't think its hypocritical because (a) I will and have a plan to adopt them very soon and (b) I am not arguing that I wont do so.  And my comments referred specifically to some people who wont change not those who cant.  I recognise that many cant afford to make the change, and I made no comment on this circumstance.

 

Im currently prevented from adopting an ASHP by my local planning authority.  I've been fighting for 2 years, and continue to fight, the battle with my LPA and, once I win, an ASHP will be in.  So I don't see how I can possibly be accused of being hypocritical on that front when the law prevents me from making the switch - many wouldn't bother with the fight!

 

Re the car, its a fine ecological balance so far as I understand it.  I dearly want (out of what I suppose could be considered avarice) to replace my 13 year old car.  However there is a very sound ecological argument, as I do only about 5k miles a year, that the embodied carbon in an EV to replace a functional fossil fuel car does not make ecological sense.  To be honest I don't know where the balance lies here, its quite possible that it lies with keeping the old motor until it is no longer functional, which I wont do because even I do occasionally like new (it will be second hand actually).  Perhaps that's the hypocrisy - buying anything new when I have a functioning old model, but for sure I wont be buying another fossil fuel powered car.  

 

The CO2 emissions from my domestic heating (about 4 tonnes per annum) significantly outweighs the contribution from the car (about 1.3 tonnes per annum) and the embodied carbon in a car far outweighs that in a boiler, so prioritizing the heating also makes ecological sense (although in reality Im pursuing them in parallel).

 

I should add that I have had solar PV since 2011.

 

Finally, neither of these technologies are 'my favoured technologies'.  They are just the only ones we currently have to mitigate two major contributions we each make to carbon emissions, without completely changing the way we live.  If there are better technologies available to do this please name them.  

 

 

 

Edited February 23 by JamesPa

[JamesPa]

10 hours ago, Roger440 said:

I posted before, but to properly insulate my house, even doing it myself, is circa £30-40K.

 

That just makes no economic sense. I (likely) wont live long enough (20 years) to break even with the reduced fuel costs. Plus i need to have that to spend, up front, in one hit.

 

New build is an entirely different proposition.

Its worth considering hitting parts only, you don't need to do the whole thing in one go or achieve passivhaus standards. 

 

There are bits of my house where, when I redecorated (room by room), it was easy to add IWI, so I did so.  Other bits less so, and I didn't.  Extra loft insulation is cheap and extremely effective.  As the glass in my 1980s double glazing has started 'blowing' I have progressively been replacing the sealed units with low E argon filled.  Together these save about 3kW at -2, on a house which is now 7.5kW at -2.  That's quite a saving in energy and money.  Obviously whether it 'pays back' 'financially' depends on life expectancy.  It probably will for me, I did most of it 10 years ago and I should, according to the stats, live more than another 10 years.  There is also however the comfort factor, better insulation = better comfort and that's not to be ignored as one gets older.

 

Of course I accept that some people cant afford these upgrades, and would be willing to pay a bit more tax to support more aggressive climate policies at the national level.   

Edited February 23 by JamesPa

[SteamyTea]

49 minutes ago, JamesPa said:

To be honest I don't know where the balance lies here, its quite possible that it lies with keeping the old motor until it is no longer functional, which I wont do because even I do occasionally like new (it will be second hand actually)

Your old car may still be useful to someone else, my latest 'new' car is 15 years old, the one it replaced was 17 years old.

The difference is the mileage the 'new' one had done 63k, the old one 245k (did not beat my Peugeot 309 that I sold at 360k and saw it being driven about with a 80k on the clock).

So it does not really matter if, from a CO_2e emission point of view how many miles you do, it is how many miles the vehicle does in total, and how long it lasts in years.

 

[ProDave]

I will add my summary of the whole "green" situation.

 

If / When I buy an EV it will be my vehicle bought at my expense for my benefit.  I will not be rushing to use it to support the grid infrastructure that should be paid for by the energy industry.  Why would I want to reduce my cars battery life and risk it not being fully charged when I want to use it?

 

I have not yet and am not in a hurry to buy An EV as my vehicle needs are perhaps more complicated than many, I want to move heavy loads, I want to tow things, I occasionally want to go on a long journey > 500 miles.  All things EV's struggle with at the moment.  If you needs are a "shopping trolley" to do mostly short journeys carrying just people and a small amount of luggage, then the present offering of EV's might meet your needs.  But I am still waiting for them to meet mine.

 

Instead I have built my own very energy efficient house heated by an ASHP.  Once the generation is sorted out and all green (beyond my control but it is heading in that direction) my house will be "green"  I have said before my previous house burned more Kerosene in a year than my car did petrol.  So I have already done more to reduce CO2 with the new house, than I would have achieved if I had bought an EV.

 

Cars are the low hanging fruit, because they generally last no more than 20 years so they should be upgraded easier than upgrading old buildings, but it does not mean replacing all ICE cars will do as much for reducing CO2 as making all homes carbon neutral, just that it is easier.

 

When building a new house, the extra cost to do it right, insulate it properly, heat it with an ASHP, make it air tight and fit MVHR is small.  This should have been mandatory for new builds 10 years ago.

 

Old houses are the problem that nobody has found a solution for.  But because we know that at some point they will need upgrading, I would not personally now buy a house worse than say EPC C unless it was substantially cheaper than a "good" house to reflect the high running costs and upgrade costs that are coming your way.

[JamesPa]

18 minutes ago, SteamyTea said:

Your old car may still be useful to someone else, my latest 'new' car is 15 years old, the one it replaced was 17 years old.

The difference is the mileage the 'new' one had done 63k, the old one 245k (did not beat my Peugeot 309 that I sold at 360k and saw it being driven about with a 80k on the clock).

So it does not really matter if, from a CO_2e emission point of view how many miles you do, it is how many miles the vehicle does in total, and how long it lasts in years.

 

Indeed so, representing yet a further complication in an already difficult calculation, with the unknowns of 'when will the car be scrapped' and 'how many miles does the new owner do compared to me?'

 

It all comes down to - "where do you draw the boundaries for the purpose of the calculation?"  Ideally (for the climate) those people who do large numbers of miles should have the relatively few electric cars that are on the road, whilst those like me who do fewer miles, should keep the fossil fuel ones going until a natural point of replacement, and then buy electric.  But of course the real world doesn't work that way. 

 

This article https://www.zerocarbonguildford.org/post/should-i-buy-an-electric-car attempts to do some calculations in several scenarios and gives values for embodied energy which are at least plausible.  

 

On balance I think I can probably justify the vehicle upgrade environmentally, albeit that its a fine balance.  So my intent is to indulge myself in a (secondhand) electric car within the next year, quite possible sooner.

 

Fortunately the calculation for domestic heating is much more straightforward.  The embodied carbon in a heat pump is order 1 tonne https://library.mitsubishielectric.co.uk/pdf/book/PUZ-WZ80VAA_TM65_Embodied_Carbon_Calculation#page-1), which means that it pays back environmentally in less than a year.  

 

[Kelvin]

Moving heavy loads is perfectly doable towing something a long way is marginal at best not least of all because the charging stations aren’t well designed to cope with anything towed. But the constant myth of you can’t go long distances in them is nonsense. We regularly do Scotland to England in ours which, door to door, is 450 miles. Takes two quickish charging stops  and we can do it in roughly the same time as we did it in the ICE car. Sure you can drive your diesel car 500 miles without stopping but few people do that in reality nor is it particularly safe. 

Edited February 23 by Kelvin

[JamesPa]

4 minutes ago, ProDave said:

I will add my summary of the whole "green" situation.

 

If / When I buy an EV it will be my vehicle bought at my expense for my benefit.  I will not be rushing to use it to support the grid infrastructure that should be paid for by the energy industry.  Why would I want to reduce my cars battery life and risk it not being fully charged when I want to use it?

 

I have not yet and am not in a hurry to buy An EV as my vehicle needs are perhaps more complicated than many, I want to move heavy loads, I want to tow things, I occasionally want to go on a long journey > 500 miles.  All things EV's struggle with at the moment.  If you needs are a "shopping trolley" to do mostly short journeys carrying just people and a small amount of luggage, then the present offering of EV's might meet your needs.  But I am still waiting for them to meet mine.

 

Instead I have built my own very energy efficient house heated by an ASHP.  Once the generation is sorted out and all green (beyond my control but it is heading in that direction) my house will be "green"  I have said before my previous house burned more Kerosene in a year than my car did petrol.  So I have already done more to reduce CO2 with the new house, than I would have achieved if I had bought an EV.

 

Cars are the low hanging fruit, because they generally last no more than 20 years so they should be upgraded easier than upgrading old buildings, but it does not mean replacing all ICE cars will do as much for reducing CO2 as making all homes carbon neutral, just that it is easier.

 

When building a new house, the extra cost to do it right, insulate it properly, heat it with an ASHP, make it air tight and fit MVHR is small.  This should have been mandatory for new builds 10 years ago.

 

Old houses are the problem that nobody has found a solution for.  But because we know that at some point they will need upgrading, I would not personally now buy a house worse than say EPC C unless it was substantially cheaper than a "good" house to reflect the high running costs and upgrade costs that are coming your way.

All very balanced if I may say so. 

 

Regarding using e-cars to support the grid, its clear that the major challenge is ensuring that the car is charged when required.  However electricity is generally cheap and plentiful overnight  so for most people, who only very rarely make long journeys overnight, it might be possible to design the problem out.  Some carefully calculated financial  incentives (which is the only way its going to work) and some guarantees about minimum charge at say 7am will likely persuade many that, so long as they have an easy to use 'just charge me and sod the cost' button that they can push when they have to do a long journey, the exchange is worthwhile.  Of course some will have a pattern of journeys that doesn't fit, thats fine its not necessary for everyone to take part.

 

Batteries are also of course interesting.  It seems that e-car batteries have turned out to be much more resilient than was initially thought/feared, but we probably wont know for certain what effect V2G has until its been tried for a fair few years.  That's a good reason for it to start early with those who, for whatever reason, it suits, so some actual data can be collected. 

[SteamyTea]

1 minute ago, JamesPa said:

"where do you draw the boundaries for the purpose of the calculation?" 

I did it after spending £2500 on it in a year.

It could have been repaired for probably £500, but as it was suffering from nearly quarter of a million miles on the suspension and steering, I drew the line.

I let the garage that had done a good job of keeping it going have it for a few quid under the scrap value.  They may strip it for spares (it had a new clutch, water pump, auxiliary pully bearing and bracket, new suspension arm, and two new tyres back in October).

The really painful bit though is that it had almost £100 of diesel in it, and without dropping the tank or punching a hole in it, there is no way to syphon the fuel out.

Was a good car and lasted me eight and a half years and 210k miles, so not really complaining. 

Hope this one can do the same mileage.  By then I will have worked out what the 26 buttons and switched that are on the steering wheel or clustered at round it do.

Then I can tackle the option on the radio.  It did get the bluetooth to connect to my phone, so can talk to people, just need to find out which 'directory' I need to fill with data to play podcasts.

And find out why I have lost the nagging woman on Google Maps.

[SteamyTea]

3 minutes ago, Kelvin said:

Sure you can drive your diesel car 500 miles without stopping but few people do that in reality nor is it particularly safe. 

I do.

My Mondeo Econotec easily does 800 miles on a tankful.

Now I must go and open the car windows so the seat can dry out, I have washed the trousers.

[Kelvin]

Sure I’ve done it too but it’s tiring driving for 8 hours non-stop. HGV drivers aren’t allowed to drive for more than 4.5 hours before stopping for a break (of 45 minutes I think) 

Edited February 23 by Kelvin

[ProDave]

6 minutes ago, Kelvin said:

Moving heavy loads is perfectly doable towing something a long way is marginal at best not least of all because the charging stations aren’t well designed to cope with anything towed. But the constant myth of you can’t go long distances in them is nonsense. We regularly do Scotland to England in ours which, door to door is 450 miles. Takes two charging stops and we can do it in roughly the same time as we did it in the ICE car. Sure you can drive your diesel car 500 miles without stopping but few people do that in reality nor is it particularly safe. 

When we do long journeys there are 2 of us sharing the driving, stops are usually dictated by the need to empty ones bladder.  Doing that and refuelling takes minutes.

 

At the moment, people are pretending that an EV is no less convenient than an ICE car.  And yes if your usual pattern of use is short journeys it probably is.  But it is not there yet for more demanding usage.  Perhaps it will get there?  Or perhaps those who want us to change to EV's might have to start being a bit more honest and admit at some times things will be a but less convenient, sometimes perhaps even downright awkward with an EV compared to an ICE.

 

We are a multiple car household, and I see the likelyhood that at some point our present small hybrid car will be replaced with an EV and that will do most of the miles, but retaining my big ICE lump for the tasks the EV is not suitable.  Particularly with me retiring, that ICE car will probably end up not doing many miles which seems a pretty good compromise to me.  I will nearer 2035 take the opportunity to upgrade it so something newer (not new) so it stands a chance of remaining in service longer.

 

But in contrasts to switching to EV's, switching from an old leaky fossil fuel fired house to an almost passive house new build heated with a heat pump gives all the benefits without a single disadvantage that I can think of to the end user and many benefits.

[Kelvin]

I’m being honest. They are no less convenient for us. In fact it powered my site before we had power and during power cuts. 
 

Edited February 23 by Kelvin

[SteamyTea]

3 minutes ago, ProDave said:

But in contrasts to switching to EV's, switching from an old leaky fossil fuel fired house to an almost passive house new build heated with a heat pump gives all the benefits without a single disadvantage that I can think of to the end user and many benefits.

On a similar argument, I have no children, so saving the planet that way.

I think the government should give me free cash because of my goodness in not inflicting generations of wasteful emissions.

And I don't inflict the little shits on anyone else.

[Roger440]

1 hour ago, JamesPa said:

Its worth considering hitting parts only, you don't need to do the whole thing in one go or achieve passivhaus standards. 

 

There are bits of my house where, when I redecorated (room by room), it was easy to add IWI, so I did so.  Other bits less so, and I didn't.  Extra loft insulation is cheap and extremely effective.  As the glass in my 1980s double glazing has started 'blowing' I have progressively been replacing the sealed units with low E argon filled.  Together these save about 3kW at -2, on a house which is now 7.5kW at -2.  That's quite a saving in energy and money.  Obviously whether it 'pays back' 'financially' depends on life expectancy.  It probably will for me, I did most of it 10 years ago and I should, according to the stats, live more than another 10 years.  There is also however the comfort factor, better insulation = better comfort and that's not to be ignored as one gets older.

 

Of course I accept that some people cant afford these upgrades, and would be willing to pay a bit more tax to support more aggressive climate policies at the national level.   

 

Ive done the easy wins. Roof already well insulated, too well as it happens as they have stuffed it down to the eaves blocking air flow. I need to resolve that, but that will actually make it worse! Lower part of roof off to resolve.

 

Plugged all the obvious air leaks, with one big one to do, but that requires removal of part of the roof, so needs to wait until summer.

 

Whilst i can bugger about on an adhoc basis, thats not going to be as good.

 

That said, even if i did it in one hit, despite the eye watering cost, it still wouldnt meet current regs. So my energy requirement whilst substantially reduced will still be significant. Which is why payback is essentially impossible.

 

Fortunately, the house is warm and cosy, better than i could have hoped for, so any program of insulation is unlikely to change things much from a comfort point of view, though UFH would be a useful gain as i do miss that. But my £30-40K doesnt include digging up the floor, just either overlay, or cuting grooves in the exsisting floor. 

 

As ProDave observes, nobody has come up with a solution for older houses. I doubt anyone will either.

 

My double glazing is early eighties, some with blown units. Even replacing these makes no economic sense. Theres a lot of glazing for a small house. It will never payback.

 

If i leave things as they are, im doing, roughly, 2000 lites of oil a year. Best case, i halve that. So now a 1000 litres. In round numbers its £1 a litre. So my investment of £30-40K at best nets me a £1000 a year saving on energy costs. Doesnt take a rocket scientist to see that it doesnt make any sense at any level.

 

There are millions of houses in the same position.

 

Id have loved to have built a house. But the planning system simply doesnt permit what i want, so no option but to buy an exsisting house. Though, realistically, i could probably never have funded such a venture.

 

 

 

[SteamyTea]

1 hour ago, Roger440 said:

My double glazing is early eighties, some with blown units. Even replacing these makes no economic sense. Theres a lot of glazing for a small house. It will never payback.

Have you actually done the sums.

My glazing is 1980s, I changed just the glass units, was, at the time, about £16 a window.  So £208.  I think the glass for the door was a lot more as it was toughened, £60.

I went from 6mm to 16mm gaps.  So a 0.4 W.m^-2.K^-1 difference.

With a total glazed area of ~8m², that is an improvement of 3.2 W.K^-1

Assuming that the mean temperature difference is 10 K, for most of the year the savings are 28 kWh.

Now that at current prices is ~£4.50/year.  Call it a fiver with the door.

So it could be argued that changing windows will never make much of a difference.

Now that is just the glazing, if I changed the frames from timber to plastic as well.

The timber frames have a U-Value of ~2 W.m^-2.K^-1, so over the year the losses are, for the 2.34m² of pine frames is 175 kWh/year.

Now I have had no luck searching for a U-Value (or R or k for that matter) for a PVC frame profile (maybe @Craig has a list).

But lets be generous and say it is half the timber frame, so a saving of 87.5 kWh/year, or £14/year (at my 16p/kWh).

I measured my frame are and my neighbours frame area (she as PVC windows).  This will reduce the total glazed area by 2.6m².  That translates to a further saving of 1.04 W.K^-1 or 9.1 kWh/year or £1.45/year.

Add that lot up and the saving is around £20/year.

Now I realise that you are not going to get new, top class windows for £2000 (payback 10 years).

I I only have a small house with only 8m² of glazing, you have a much greater area, so will work out cheaper per square metre to replace them.

Worth doing the sums.  I did and fitting some secondary internal glazing (making it in effect triple glazing) made a difference (about £150 but could have done it cheaper if I had bought full size sheets of polystyrene rather than half size sheet).

One thing I allowed me to do was reduce the time the heating is on (from a mean of 10°C OAT to 9°C OAT, which is about a month in time terms).

 

 

[Roger440]

17 minutes ago, SteamyTea said:

Have you actually done the sums.

My glazing is 1980s, I changed just the glass units, was, at the time, about £16 a window.  So £208.  I think the glass for the door was a lot more as it was toughened, £60.

I went from 6mm to 16mm gaps.  So a 0.4 W.m^-2.K^-1 difference.

With a total glazed area of ~8m², that is an improvement of 3.2 W.K^-1

Assuming that the mean temperature difference is 10 K, for most of the year the savings are 28 kWh.

Now that at current prices is ~£4.50/year.  Call it a fiver with the door.

So it could be argued that changing windows will never make much of a difference.

Now that is just the glazing, if I changed the frames from timber to plastic as well.

The timber frames have a U-Value of ~2 W.m^-2.K^-1, so over the year the losses are, for the 2.34m² of pine frames is 175 kWh/year.

Now I have had no luck searching for a U-Value (or R or k for that matter) for a PVC frame profile (maybe @Craig has a list).

But lets be generous and say it is half the timber frame, so a saving of 87.5 kWh/year, or £14/year (at my 16p/kWh).

I measured my frame are and my neighbours frame area (she as PVC windows).  This will reduce the total glazed area by 2.6m².  That translates to a further saving of 1.04 W.K^-1 or 9.1 kWh/year or £1.45/year.

Add that lot up and the saving is around £20/year.

Now I realise that you are not going to get new, top class windows for £2000 (payback 10 years).

I I only have a small house with only 8m² of glazing, you have a much greater area, so will work out cheaper per square metre to replace them.

Worth doing the sums.  I did and fitting some secondary internal glazing (making it in effect triple glazing) made a difference (about £150 but could have done it cheaper if I had bought full size sheets of polystyrene rather than half size sheet).

One thing I allowed me to do was reduce the time the heating is on (from a mean of 10°C OAT to 9°C OAT, which is about a month in time terms).

 

 

I think your maths might be a touch off. 10 x 20 = 200, not 2000

 

Have i properly calculated? No. i havent. 

 

However, they are already UPVC, apart from front door. And look something like 18mm.

 

Looking at the frames, which are very slender, i cant see any realistic way of putting something deeper in there.

 

So, sensibly, yes, i should replce the blown units. Low cost, and gets me back to how they should be. But thats going to have almost no appreciable effect on the overall cost.

 

My costings were done based on replacing with new units. Because thats the only way to make any worthwhile gains. Which will be into 5 figures for the whole house.

[SteamyTea]

1 minute ago, Roger440 said:

I think your maths might be a touch off

I have a light touch on the keyboard, or a heavy touch if I am thinking about other things.

 

Can you add a layer of insulation around the inner frame.

 

It does make me wonder if the energy saving benefits of new windows is oversold, would have to do some real research as much of it depends on the wall to window area.

Both my neighbours had plastic windows fitted to save painting them, I just bought a £600 scaffold tower and can sort them in a couple of sunny days.