Heat in Buildings Strategy Statement

[ProDave]

7 minutes ago, gravelld said:

I was wondering the other day how much cumulative energy is lost through all the downlighters over the country that vent into an unheated loft space. Their popularity since the early 00s must mean there are a lot of these, and I rarely see them properly sealed.

 

I remember when I fixed my loft - first job was clearing it out, then before re-insulating, it needed massive air tightness treatment. We had around twenty downlighters just venting into the loft - put your hand over them when it was cold in the loft and you really felt it. On the other hand, if the wind is blowing the right (or wrong, depending on your perspective) way you can feel the down draught being forced into the building.

 

Did the old clay plant pot trick (and changed to LEDs of course) and I think that was the single biggest intervention I've made on air tightness!

As an electrician, I cringed at all the times I removed a perfectly good (if ugly) 54W flourescent light from a kitchen and replaced it with 300W or more of halogen downlighters.  That was even before you considered the need to make holes in any insulation that was there so they did not cook and catch fire.  the Halogen downlighter promoted by all the trendy tv make over programs has probably been responsible for a huge increase in lighting energy usage over the last 20 years.

 

Only now, with LED lamps, and in a warm roof house so there is no ceiling level insulation or air tightness to worry about will I have downlighters in my own house.

[billt]

17 hours ago, saveasteading said:

Many houses have hardly any insulation, I believe, or 50mm from when it was a new idea and 2". They would benefit from another 150.

After that there is diminishing return (in my opinion but never proven) and I am surprised that 500mm is mentioned as a possibility.

 

I doubt that many houses are left with no loft insulation, there have been so many subsidised or free schemes.

 

From a cost effectiveness POV significant diminishing returns probably start at 100mm or less. I only used 500m as that's what i put in my last house; it's cheap and easy. I might put a similar amount in this house.

 

17 hours ago, saveasteading said:

What would be your choice for 1. cynical improvement of epc at least cost?

2. Best value for actual improvement?

 

I don't really know, it depends on the state of the house to start with, but developers seem to put a few PV panels on many cheap developments, so thath's probably a cheap way to scrape through the SAP requirements.

 

Best value would be draught proofing and loft insulation, if they are missing. Economically the others aren't worth doing although double glazing can improve comfort and reduce condensation and upvc double glazed units can be had fairly inexpensively.

 

An ASHP is completely pointless. It will most likely make the EPC worse than a mains gas boiler and cost more to run (unless gas prices double and electricity prices stagnate - a most unlikely circumstance.

[billt]

17 hours ago, Ferdinand said:

57 to 67 seems to be quite a lot to me.

 

How much C02 and kWh did that say it saved?

 

Total energy use was 45,296 and 33,805, CO2 was 9623 and 7141.

 

We have inherited a gas fire which is never used. The calculator says that uses 8,600kWh/year while the main system uses only 33,000 kWh/year. Don't you love assumptions.

 

Yes, it's a significant reduction in energy use but it doesn't move the EPC from a D into the proposed legal requirement of C, let alone a potential B

 

Using an arbitrary letter from a flawed assessment system as a basis for legislation is madness.

[saveasteading]

3 minutes ago, billt said:

a flawed assessment system

Our daughter renovated a Victorian terrace house. We stripped the lath and fitted insulation everywhere. An EPC person came for some reason (mortgage?) and would not allow anything that wasn't standard, ie all assumptions. Therefore every building of this type will get the same rating, allowing only for dimensional changes.

I didn't meet him but I think he was unskilled and uninterested, using a simple programme, and probably working for the company that bid lowest.

[SteamyTea]

1 hour ago, billt said:

From a cost effectiveness POV significant diminishing returns probably start at 100mm or less.

Not really the way to look at it.

The idea is that energy usage is reduced, preferably to a level where domestic PV, a long with HP technology can balance each other.

It is not to do with the actual cost, complexity or return on the insulation required.

[Ferdinand]

1 hour ago, saveasteading said:

Our daughter renovated a Victorian terrace house. We stripped the lath and fitted insulation everywhere. An EPC person came for some reason (mortgage?) and would not allow anything that wasn't standard, ie all assumptions. Therefore every building of this type will get the same rating, allowing only for dimensional changes.

I didn't meet him but I think he was unskilled and uninterested, using a simple programme, and probably working for the company that bid lowest.

 

How did you evidence the extra insulation? And how much of it was there?

 

(When I renovate something, I make sure there is somewhere the detail can be viewed, or have documentary proof.)

 

If they do not see evidence, there is a series of assumptions in the procedure they have to follow instead.

 

If they insist on following the assumptions despite the sufficient evidence for an easy life, then afaics you need to make them correct, or get a different EPC or a later EPC of your own if you need it for your purposes.

 

 

[Ferdinand]

1 hour ago, billt said:

 

Total energy use was 45,296 and 33,805, CO2 was 9623 and 7141.

 

We have inherited a gas fire which is never used. The calculator says that uses 8,600kWh/year while the main system uses only 33,000 kWh/year. Don't you love assumptions.

 

Yes, it's a significant reduction in energy use but it doesn't move the EPC from a D into the proposed legal requirement of C, let alone a potential B

 

Using an arbitrary letter from a flawed assessment system as a basis for legislation is madness.

 

I tend to think that the boilerplate recommendations are the most flawed area, and that the way they are calculated is not actually that bad for what they cost (which is a tiny amount of money - subject to me not currently recalling how they handle air leakage).

 

And perhaps the rubber-stamping approach by owners / developers / estate agents is a weakness - though I can't see a way around that without a permanent hike in energy prices; that is the only time mainstream people seem to pay attention.

 

(Warning: Fag paper arithmetic incoming)

 

However, even a saving of say 1 tonne kg of C02 per property per year, multiplied by 22-23 million houses, would be 22-23 million tonnes per year.

 

Which is nearly 5% of the current UK total.  

 

[SteamyTea]

1 hour ago, Ferdinand said:

though I can't see a way around that without a permanent hike in energy prices; that is the only time mainstream people seem to pay attention.

Probably the same people that bleat the loudest about green taxes, energy companies ripping them off, and have never read their meters.

[ProDave]

My EPC came with the following 2 recommendations:

 

solar water heating.  Cost £3000 - £6000 saving over 3 years £309  (so payback time between 30 and 60 years)

 Wind turbine    cost £15000 -£25000  saving £2052 over 3 years (so payback time 22 to 44 years)

[saveasteading]

3 hours ago, Ferdinand said:

insist on following the assumptions

It didn't matter to us, but the guy said absolutely no, they had no interest in re-running it. 

The reason for mentioning it is that this was another bad example of incompetents (or worse) doing assessments, and I wonder what the standards will be when the need arises to check the nation's property.

[saveasteading]

1 hour ago, ProDave said:

solar water heating.  so payback time between 30 and 60 years

 Wind turbine    so payback time 22 to 44 years

The monetary payback target of 10 years is often a good guide to the carbon payback, unless there are subsidies.

These small scale solar panels and wind turbines cost a lot of carbon to make and and bring from China, possibly never recover it.  

And they wont last 30 years anyway.

Someone gets paid to give us this rubbish advice.

 

How long ago was this? Surely nobody is suggesting small wind turbines any longer.

[ProDave]

12 minutes ago, saveasteading said:

It didn't matter to us, but the guy said absolutely no, they had no interest in re-running it. 

The reason for mentioning it is that this was another bad example of incompetents (or worse) doing assessments, and I wonder what the standards will be when the need arises to check the nation's property.

I remember Jeremy trying to get an EPC on his old house when he sold it, providing the assessor with documentary evidence on all the improvements he had made, which he promptly ignored and just used the standard assumptions

 

I was looking again at my own EPC (A94) and in the report it states my estimated annual heating and hot water costs.  Well my actual costs are about 1/3 of their estimate, even based on the current higher electricity price.  Since CO2 emissions are largely linked to energy usage, I wonder what the EPC would have come out as , if it had accurately predicted the energy usage, not a 3 times over estimate?  and for clarification, I worked out my estimated energy use using Jeremy's heat loss calculation spreadsheet, and that simple spreadsheet gave an almost perfect estimate of the energy usage, very much closer to real use than this SAP assessment did.

 

I think there is little hope for ever getting a meaningful surveyors estimate of any form.  Surely a FAR more accurate and easier way would just be to go by the actual metered energy use of a house in a 12 month period?

[ProDave]

8 minutes ago, saveasteading said:

The monetary payback target of 10 years is often a good guide to the carbon payback, unless there are subsidies.

These small scale solar panels and wind turbines cost a lot of carbon to make and and bring from China, possibly never recover it.  

And they wont last 30 years anyway.

Someone gets paid to give us this rubbish advice.

 

How long ago was this? Surely nobody is suggesting small wind turbines any longer.

Just a few weeks ago.

[saveasteading]

8 minutes ago, ProDave said:

17 minutes ago, saveasteading said:

How long ago was this? Surely nobody is suggesting small wind turbines any longer.

Just a few weeks ago.

It must be 10 years since sensible people stopped considering these. 

However I went to a BRE talk perhaps 5 years ago where they still suggested wind turbines and small hydro schemes for individual houses.

The same organisation wrote the EPC programme that everyone has to use, hence the nonsense therein. 

 

For example, unless recently changed, it automatically assumes that an ASHP will also be used for cooling, and adds that to the power use.

It is all in the back pages, if you insist on getting them.

[ProDave]

3 minutes ago, saveasteading said:

For example, unless recently changed, it automatically assumes that an ASHP will also be used for cooling, and adds that to the power use.

It is all in the back pages, if you insist on getting them.

That could be why my SAP estimated the energy usage to be about 3 times what a simple heat loss spreadsheet, and real world bills suggests.

 

I guess I am in an unusual position of not getting the final as built SAP done until I have at least 2 full years of real world energy usage data available.

[Gone West]

24 minutes ago, ProDave said:

Surely a FAR more accurate and easier way would just be to go by the actual metered energy use of a house in a 12 month period?

But doesn't there have to be a standard for the indoor temperature otherwise the comparisons are meaningless. Running a house at 18C downstairs and 16C upstairs is always going to look better than 23C throughout the house.

[ProDave]

2 minutes ago, Gone West said:

But doesn't there have to be a standard for the indoor temperature otherwise the comparisons are meaningless. Running a house at 18C downstairs and 16C upstairs is always going to look better than 23C throughout the house.

For my calculation and real world costs, I work on 20 degrees inside.  I don;t believe it would triple my energy usage if I wanted 23 degrees not 20

[Gone West]

2 minutes ago, ProDave said:

For my calculation and real world costs, I work on 20 degrees inside.  I don;t believe it would triple my energy usage if I wanted 23 degrees not 20

No it wouldn't triple it but I was surprised when I ran PHPP for my last house how much difference it makes, everything else being equal.

9kWh/m2a @ 18C

13kWh/m2a @ 20C

21kWh/m2a @ 23C

 

[SteamyTea]

2 minutes ago, Gone West said:

No it wouldn't triple it but I was surprised when I ran PHPP for my last house how much difference it makes, everything else being equal.

9kWh/m2a @ 18C

13kWh/m2a @ 20C

21kWh/m2a @ 23C

 

It is why they say turning down your heating can save 20% on your energy bill.

It is, in part, to do with incidental gains i.e. passive solar, cooking, bathing etc.

It is also, in part, to do with external temperature variations, which follow, quite closely, a normal distribution curve.

[ADLIan]

Remember that SAP rating estimates the energy use and cost of a house under standardised conditions so that the energy efficiency of houses may be compared - in this respect it is similar to the mpg rating of a car and is very unlikely to reflect an individual's occupancy, heating pattern, temperature settings, hot water use etc, etc.

 

The RDSAP system for existing houses is not fit for purpose simply because the fees have been forced down to such a low level. Assessor probably gets less than £50 to travel to the house, do a 'full' survey and then collect the correct evidence to get anywhere near an accurate assessment, hence corner cutting and the easy option of ticking 'default' values.

 

@saveasteading Can you point me in the direction of ASHP assumed to be used for cooling too? I'm not aware of this one.

 

 

[Ferdinand]

3 hours ago, ProDave said:

I remember Jeremy trying to get an EPC on his old house when he sold it, providing the assessor with documentary evidence on all the improvements he had made, which he promptly ignored and just used the standard assumptions

 

I was looking again at my own EPC (A94) and in the report it states my estimated annual heating and hot water costs.  Well my actual costs are about 1/3 of their estimate, even based on the current higher electricity price.  Since CO2 emissions are largely linked to energy usage, I wonder what the EPC would have come out as , if it had accurately predicted the energy usage, not a 3 times over estimate?  and for clarification, I worked out my estimated energy use using Jeremy's heat loss calculation spreadsheet, and that simple spreadsheet gave an almost perfect estimate of the energy usage, very much closer to real use than this SAP assessment did.

 

I think there is little hope for ever getting a meaningful surveyors estimate of any form.  Surely a FAR more accurate and easier way would just be to go by the actual metered energy use of a house in a 12 month period?

 

That undermines the "standard", though.

 

It's the old unanswerable one about the impact of different types of occupation, and are they to be taken into account.

 

If you don't take them into account, then the actual numbers for an under-occupied 4-bed house such as yours or mine (I am one person in 200sqm) don't match, but if we do take it into account then it is difficult to compare your or my house with another one with a family of 5 in it.

 

The dilemma  is unresolvable, so you have to make some decisions and accept the compromises. 

[ProDave]

3 minutes ago, Ferdinand said:

 

That undermines the "standard", though.

 

It's the old unanswerable one about the impact of different types of occupation, and are they to be taken into account.

 

If you don't take them into account, then the actual numbers for an under-occupied 4-bed house such as yours or mine (I am one person in 200sqm) don't match, but if we do take it into account then it is difficult to compare your or my house with another one with a family of 5 in it.

 

The dilemma  is unresolvable, so you have to make some decisions and accept the compromises. 

In Jeremy's case he had improved the insulation in the building but they ignored that and just used a standard guess at what the typical insulation levels would be for that type of property.  That is not "undermining the standard"  That it taking into account what the building actually is.  If this attitude does not change, how do you improve the EPC rating of a building by insulating the walls if the assessor is going to ignore it?  Or is it just a "jobs for the boys" scheme that you only take the improvements into account if done by some company who is a member of some over charging scheme again?

 

If anything, an under occupied building should cost more to heat as less incidental heat input.

[Trw144]

On 11/10/2021 at 16:48, IanR said:

 

Is Biomass an alternative? It's still incentivised as a low carbon heating source, but it's not low emissions

Particulates? All the decent biomas kit now has the option electrostatic filters added to minimise the emissions. In Germany you now receive a bigger grant if the filter is added.

[IanR]

36 minutes ago, Trw144 said:

Particulates? All the decent biomas kit now has the option electrostatic filters added to minimise the emissions. In Germany you now receive a bigger grant if the filter is added.

 

But, alas, our allowable particulate limits on Biomass heating are appalling in the UK, when compared to, say, transport.

 

I was referring to Particulates and NOx in the main.

[Trw144]

13 minutes ago, IanR said:

 

But, alas, our allowable particulate limits on Biomass heating are appalling in the UK, when compared to, say, transport.

 

I was referring to Particulates and NOx in the main.

Agreed, and certainly an area that needs tightening up on moving forward.