Total energy consumption per m2 per annum

[NSS]

2 minutes ago, NSS said:

How the he'll was that a pop at you? 

 

3 minutes ago, jack said:

 

I took it as a pop at the people that couldn't give a toss etc, definitely not a pop at you.

Not so much those that couldn't give a toss, more those (policy makers and their advisors) behind these 'standards. Far more effective IMHO if you could just quote a total energy cost per square metre. For example, two newly built houses are built by two developers on the same street.  House A is a £10k cheaper than house B, but they're the same size, same layout, same spec (in terms of finish), most would buy house A without giving a it a second thought. But if house A's energy costs are twice or three times those of house B (and that was clear as an energy cost per m2), maybe people would be more inclined to buy house B and, in doing so, encourage the builder of house A to up their game.

[Declan52]

How would you work out the solar PV aspect of your running costs. My wood pellet fuel is pretty easy as I know the quantity I am buying in but how would I guage what amount of pv excess I use during the year to heat my water. I have the generation amount and how much I sold back but how would you split the difference. Some the house will have used to power various things and the rest will have been used by the immersion.

[Ed Davies]

2 hours ago, JSHarris said:

It's primary energy that is used in the PH max allowable figure of 15 kWh/m²/year for space heating. 

Are you sure? My understanding (though I can't cite a reference which is specific - I think you'd have to look in the PHPP spreadsheet to be sure) is that the 15 kWh/(m²·a) or 10 W/m² figures were for final/delivered energy. It's the 120 kWh/(m²·a) for all energy use which is primary, I believe.

 

Part of the reason I think this is that the 10 W/m² figure is based on the heat that can reasonably be delivered via the MHRV (without getting a burning smell and without forcing extra air through). That has nothing to do with the amount of primary energy involved. Also, the huge difference between 15 and 120 is not just a matter of non-space-heating energy use. Even including DHW I think it has to include headroom for the primary vs final multiplication as well.

 

1 hour ago, Ferdinand said:

The passive house standard really needs updating a bit now, IMHO,

Yes, I think they have. The standard you're referencing is now called “Classic”, there are now “Plus” and “Premium” classes which are a bit more ambitious AIUI.

Edited August 24, 2018 by Ed Davies

[NSS]

13 minutes ago, Declan52 said:

How would you work out the solar PV aspect of your running costs.

I presume it would be a case of fitting an export meter, though the downside of that (if you're using more than 50% of what you generate) could be a reduction in FiT payments if you had the declare the actual export amount.

[Jeremy Harris]

You may be right about PHPP, @Ed Davies, I've not looked at it for a long time, and just recall that is used conversion factors for total energy somewhere in the spreadsheet.  I know that SAP does use conversion factors for fuel type though, so the EPC rating is highly dependent on fuel type for a given size and standard of dwelling.

[Declan52]

2 minutes ago, NSS said:

I presume it would be a case of fitting an export meter, though the downside of that (if you're using more than 50% of what you generate) could be a reduction in FiT payments if you had the declare the actual export amount.

My electric meter already measures what I export. I get roughly £60 back a year from what I send back to the grid. 

[newhome]

9 minutes ago, Declan52 said:

My electric meter already measures what I export. I get roughly £60 back a year from what I send back to the grid. 

 

Doesn’t that only work if you are signed up to receive FIT payments though? If you are not, or you have a mix of FIT and non FIT there would need to be a different way of measuring it. And what about solar thermal? How would you measure that? 

[Declan52]

I am signed up for the fit scheme. I got £545.67 back this year so my house is generating enough money to cover my yearly electric costs. Plus I then have close on free hot water from may to September. I think between them dates this year I have had to put the stove on 3 times as the sun wasn't enough to heat the tank fully.

[gravelld]

4 hours ago, NSS said:

But if house A's energy costs are twice or three times those of house B (and that was clear as an energy cost per m2), maybe people would be more inclined to buy house B and, in doing so, encourage the builder of house A to up their game.

 

The trouble with this is, without independent rigorous assessment, you don't know B will actually perform like that.

 

@NSS your house is around AECB Silver levels, well done!

[pdf27]

7 hours ago, Ed Davies said:

Are you sure? My understanding (though I can't cite a reference which is specific - I think you'd have to look in the PHPP spreadsheet to be sure) is that the 15 kWh/(m²·a) or 10 W/m² figures were for final/delivered energy. It's the 120 kWh/(m²·a) for all energy use which is primary, I believe.

 

Part of the reason I think this is that the 10 W/m² figure is based on the heat that can reasonably be delivered via the MHRV (without getting a burning smell and without forcing extra air through). That has nothing to do with the amount of primary energy involved. Also, the huge difference between 15 and 120 is not just a matter of non-space-heating energy use. Even including DHW I think it has to include headroom for the primary vs final multiplication as well.

 

Yes, I think they have. The standard you're referencing is now called “Classic”, there are now “Plus” and “Premium” classes which are a bit more ambitious AIUI.

Yep, 15 kWh/m²/year or 10W/m² peak demand (AIUI you can choose either criteria, but they typically come out pretty close to one another) are the delivered heating values, measured as heat. Essentially they're the "comfort" side of the equation - if you're that low (roughly) you won't have any problems with cold draughts, variable temperatures, etc. The 10W/m² is also set by the practical limit for heat delivery via the MVHR system at no more than 50°C (the burning smell limit) from resistance heat - a cheap way of doing things but I'm not convinced that it's a particularly good one.

 

The 120 kWh/m²/year primary energy in the older version of the standard is the environmental impact side of the equation - they've now essentially translated it into electricity (sorta) from primary energy and revised the targets to be quite a bit lower to match the earlier standard, more or less:

PER is essentially a way of trying to match supply and demand of renewable energy by penalising use when there isn't renewable generation available. If you're using it at the time of generation it counts as 1 unit of power used for 1 generated. If it's in short term storage (heat, battery) it's a bit less, if in long term storage (electricity to gas) it's a lot less. They then add in country-specific factors to allow for when demand is likely to occur versus what resources are available (so Norway will be just fine with all the hydro - the UK will be worse with lots of wind, and somewhere relying only on PV will be hit very badly I suspect).

[NSS]

3 hours ago, gravelld said:

 

The trouble with this is, without independent rigorous assessment, you don't know B will actually perform like that.

 

@NSS your house is around AECB Silver levels, well done!

Yep, and energy use will, for example, vary according to the number of inhabitants, their lifestyle, etc, but I merely think that the one number almost everyone will understand is one that gives them an indication of the money it will cost for the energy one home will use when compared to the next. That's what EPCs are supposed to do, but very few people even read them.

 

As for my own motivation for projecting this cost per m2 per annum, it came in part out of a conversation in the pub with mates, trying to explain how much cheaper our house is to run than our previous property. That was a circa 190m2 house built in the late 80's. Our total energy costs there equated to more than double the kWh/m2a of the new house. There's still only two of us living in it, so it follows that the major difference in cost will largely have been due to the space heating cost (due to the relatively poor air-tightness and insulation). 

 

As for the AECB standard you mention, thank you (I think) but like the vast majority of Joe Public, certificates are of no particular interest to me, the piece of paper (virtual or otherwise) that matters is the energy bill.

 

In short, I personally feel (and this is not a dig at any of you who strive for one standard or another) that the way to encourage more energy efficient homes is to sell the cost saving potential to buyers, not that it has passed some (to them) meaningless standard.

Edited August 24, 2018 by NSS

[Jeremy Harris]

4 hours ago, NSS said:

In short, I personally feel (and this is not a dig at any of you who strive for one standard or another) that the way to encourage more energy efficient homes is to sell the cost saving potential to buyers, not that it has passed some (to them) meaningless standard.

 

I wholeheartedly agree.  When we were selling our old house recently (which is by no means energy efficient - it's the best I've been able to do to reasonably improve a 1986 bungalow with solid floors), I did print out all the bills, including the energy bills, and had them laid out on the dining room table.  I also knocked up a single sheet with the total prices for everything per month and per annum (so energy bills, council tax and water and sewerage bills).  I also had a copy of the (now mandatory) EPC printed out.

 

What we found was that pretty much every potential buyer was interested in knowing how much the running costs were, no one was the slightest bit interested in the EPC band, which pretty much proves, albeit anecdotally, exactly what you've said.

 

There were lots of comments along the lines of "That's about the same as we're paying now", or "that's a lot cheaper than our current house".  Having a summary of the costs seemed to be useful, as few were interested in actually checking the bills I'd printed out, other than one or two that wanted to confirm the Council Tax band.

[newhome]

9 minutes ago, NSS said:

is to sell the cost saving potential to buyers

 

@ProDave said no one who viewed his house seemed interested in the FIT payments.

 

I went with some friends to view a house the other week. It was a second viewing. They hadn’t asked anything about running costs and wouldn’t have done so even being really interested in the house. I asked the guy what the heating was. Oil he says. Didn’t know what type of cylinder it was, top of the range was all he said (it was a Telford UVC cos I looked). 

 

EPC report was D with a potential for C. I asked what could take it to a C. No idea he says. Estate agent in 10 inch stilettos whose every other word was fantastic was clueless too. At present sellers don’t care and buyers don’t care! 

[NSS]

18 minutes ago, newhome said:

 

@ProDave said no one who viewed his house seemed interested in the FIT payments.

 

I went with some friends to view a house the other week. It was a second viewing. They hadn’t asked anything about running costs and wouldn’t have done so even being really interested in the house. I asked the guy what the heating was. Oil he says. Didn’t know what type of cylinder it was, top of the range was all he said (it was a Telford UVC cos I looked). 

 

EPC report was D with a potential for C. I asked what could take it to a C. No idea he says. Estate agent in 10 inch stilettos whose every other word was fantastic was clueless too. At present sellers don’t care and buyers don’t care! 

The obvious answer is, don't leave buyers to ask, force sellers to tell. If on sales particulars, alongside the the sale price, sellers had to declare the 'average energy cost per annum' and highlight that number in a colour coded box (green is good, red is bad type of thing), then people would soon start to take notice.

[newhome]

Just now, NSS said:

The obvious answer is, don't leave buyers to ask, force sellers to tell. If on sales particulars, alongside the the sale price, sellers had to declare the 'average energy cost per annum' and highlight that number in a colour coded box (green is good, red is bad type of thing), then people would soon start to take notice.

 

Yes I’m in no way saying that what you are suggesting is a bad thing but it was an eye opener going to that house viewing. Complete apathy on both sides. 

[NSS]

2 minutes ago, newhome said:

 

Yes I’m in no way saying that what you are suggesting is a bad thing but it was an eye opener going to that house viewing. Complete apathy on both sides. 

Is it apathy or ignorance? Perhaps, at least in the short term, the EPC could be used to draw attention, much like appliances have to have their energy rating clearly indicated. Putting a big colour coded box with the EPC band and a bold 'excellent,' 'very good', 'good', 'poor', 'very poor' or 'dreadful energy efficiency' alongside the house price would at least be a start.

[newhome]

I think in that case it was apathy. An expensive house, fairly wealthy cash buyers and wealthy sellers who are only moving as they want a lower maintenance property (this one has paddocks) as they spend 6 months of the year in Cyprus. Guess a few bills weren’t that much of an issue to either party. If you are borrowing and on a tight budget these things are a lot more important I guess. 

[Jeremy Harris]

Personally I'm convinced that putting the actual last year or twos running cost in the advert would be more effective than any form of energy performance certificate.  It's hard to ignore something that says "This house costs around £4000 a year to run" in the details, perhaps with a breakdown into Council Tax, water and sewerage charges and energy bills.

 

As an example, the 3 bedroom, 1986 built, bungalow that (I hope!) we've just sold had an annual running cost of £3,877.28 a year (£2081.32 Council Tax, £969.96 gas and electricity combined, £826 water and sewerage).

 

The house we've just built has an annual running cost of £1,601.12 (£2081.32 Council Tax, -£480.20 electricity, no water or sewerage charges).

 

 

 

 

 

[ProDave]

1 hour ago, newhome said:

 

@ProDave said no one who viewed his house seemed interested in the FIT payments.

 

I went with some friends to view a house the other week. It was a second viewing. They hadn’t asked anything about running costs and wouldn’t have done so even being really interested in the house. I asked the guy what the heating was. Oil he says. Didn’t know what type of cylinder it was, top of the range was all he said (it was a Telford UVC cos I looked). 

 

EPC report was D with a potential for C. I asked what could take it to a C. No idea he says. Estate agent in 10 inch stilettos whose every other word was fantastic was clueless too. At present sellers don’t care and buyers don’t care! 

Yes indeed.

 

It appears that nobody cares about the running cost of a house. Yet they will only buy an A+++ rated fridge.

 

The fact that the FIT payments for our old house just about paid for the annual electricity bill (and probably would pay it 100% if we took more trouble to save usage a bit) was irellevant to most people.  The running costs of that house are about £1200 per year in heating oil, and the council tax (which is the dominant bill with nothing you can do about it * )  I still suspect that our new low energy house, might actually cost more per year to run than the old house, because there will be no FIT subsidy.

 

I know of one case where a house sale fell through because of solar PV.  A friend of SWMBO was looking for a house, and they found a detached house, with ownwer owned solar PV on the original high rate FIT.  I advised them to buy it.  But the sale fell through because the surveyor mentioned that the roof might not be adequate to support the extra load of the PV panels, and might have damaged the tiles and they might need replacing.  They pulled out, and ended up buying a semi detached house without PV.  I felt sorry for the vendors, and for them missing out and ending up with a less good house.

 

 

* I might have mentioned "council tax poverty"  IT has often been stated if you spend 10% of your income on fuel, then you are in "fuel poverty"  Well for some time we have been in the situation, where we spend more on council tax, than we do on fuel, with no way to reduce the council tax bill.  Since the council tax is 10% of our income, I declare that we are in "council tax poverty"

 

And before you ask, we don't qualify for any of the low income council tax reliefs, because our assets are way too high.

[gravelld]

3 hours ago, NSS said:

That's what EPCs are supposed to do, but very few people even read them

 

It's irrelevant whether they read them or not; EPCs are of no use for assessing the performance of a house because the surrounding processes do not derive trusted, rigorous or representative results.

 

3 hours ago, NSS said:

In short, I personally feel (and this is not a dig at any of you who strive for one standard or another) that the way to encourage more energy efficient homes is to sell the cost saving potential to buyers, not that it has passed some (to them) meaningless standard.

 

This was tried, albeit with retrofit, with the Green Deal. It failed miserably, mainly because energy is too cheap to really derive impactful financial results (but also because intervention is expensive in retrofit). Energy is not a big enough cost to worry people when they have "location location location", "character fireplaces", bi fold doors, and living as far away from certain people as possible to worry about.

Edited August 24, 2018 by Nickfromwales

[NSS]

1 minute ago, gravelld said:

 

It's irrelevant whether they read them or not; EPCs are of no use for assessing the performance of a house because the surrounding processes do not derive trusted, rigorous or representative results.

Except to say that you can, presumably, be fairly confident that a house rated as an A is likely going to be comparatively more energy efficient than one with a C, D or worse rating.

[Jeremy Harris]

12 minutes ago, ProDave said:

* I might have mentioned "council tax poverty"  IT has often been stated if you spend 10% of your income on fuel, then you are in "fuel poverty"  Well for some time we have been in the situation, where we spend more on council tax, than we do on fuel, with no way to reduce the council tax bill.  Since the council tax is 10% of our income, I declare that we are in "council tax poverty"

 

We've been in the same position for years; the dominant house running cost is always the Council Tax (currently £2081.32 p.a. for each of our two houses, soon to be one, with luck).  Our energy costs at the old house have never exceeded half that, so in relative terms, energy has never been close to being the dominating running cost.  The other real killer down here are water and sewerage charges.  We're reasonable frugal with water, but we still spend almost as much on water and sewerage charges  as we do on energy.

 

I'm actually pretty pleased that circumstances pretty much forced us into drilling a borehole for water and fitting a treatment plant, as, although both add to our energy usage, the overall cost is a tiny fraction of the price we'd pay for mains water and sewerage.

[ProDave]

2 minutes ago, gravelld said:

 

It's irrelevant whether they read them or not; EPCs are of no use for assessing the performance of a house because the surrounding processes do not derive trusted, rigorous or representative results.

I think you are right that the present system has no trust.  Look at @JSHarris house. He had accurately modeled the structure of the house and determined it would warrant a C, but the assessor had his own ideas, made sweeping assumptions ignoring the facts he was given and gave a poorer rating.

 

But people still buy old houses with an EPC of F or G, and then complain they are cold, damp, and cost a fortune to heat.

[gravelld]

Just now, NSS said:

Except to say that you can, presumably, be fairly confident that a house rated as an A is likely going to be comparatively more energy efficient than one with a C, D or worse rating

 

No way. My house is C rated. PHPP calculates heating alone at 165kWh/m²a. I know which one I trust.

 

Edit: @ProDave is suggesting my house has a similar EPC rating to Jeremy's! Case closed imo. 

Edited August 24, 2018 by gravelld

[Guest Alphonsox]

My mothers place got an EPC rating of band G-1and this was a place with 3-4 ft thick solid stone walls and a solid slate roof. (I think a tent would get better result). I thought this  was a remarkable, but of the 100+ people we showed around the place no-one remarked on it. At the very least I was expecting a comment to the fact that it couldn't be any lower no matter what alterations they decided to make.

 

A pointless expense in my view.