The BFRC Window Energy Rating Scheme
Dear Customer,
We feel that it is incumbent on Thermoseal Group to inform you of our concerns regarding the development of the GGF/BFRC WER scheme. Please note the following comments summarise our views based on the limited information supplied to Thermoseal Group by the GGF/BFRC. We suggest you contact the GGF/BFRC for clarification on the points raised and we recommend that individuals check the facts for themselves.
- Under the consultation papers issued by the Department for Communities and Local Government in June 2009, the proposed amendments to Part L essentially mean that in existing dwellings, to show compliance with the Building Regulations it will be necessary to ensure that windows are fitted that have a minimum WER (Window Energy Rating) of Band C. The effect of this is that the WER scheme becomes the single performance standard by which to show compliance with Part L in respect of controlled units in the UK.
- As the BFRC is the sole organisation to administer the WER scheme, it follows that the BFRC is effectively the monopoly provider of the WER in the UK. It is the only organisation set up as an approver of simulations and the sole organisation with which to register for a WER. It is the sole provider of licences. The BFRC provides an economic service to those requiring simulations and licences as it charges fees for these services.
- The rating and licence that the BFRC provides is for the entire window unit. I.e. a rating will only be given in relation to a complete unit and not to individual components that make up the unit. In simple terms this means that should one of those components change (e.g. the glass), even if that component is of the same or superior specification, the previous rating will not apply and a new simulation must be carried out and paid for.
- We believe the current BFRC scheme unfairly favours window companies and fabricators. It does not offer any method for a glass sealed unit manufacturer to demonstrate compliance with the regulations. At present many installers and window companies (i.e. the companies that fit windows to properties and deal with the end consumer) buy their window frames from fabricators and their glass from sealed unit manufacturers. The WER scheme effectively means that fabricators are consolidating control of the market by refusing to allow customers (the installers etc) to use their license unless they purchase their sealed units from them.
- The proposed WER scheme stops new IG products from entering the UK market. Once a fabricator or window company has a simulation with a selection of WER products listed, there is no incentive to improve or innovate on the units with superior components. This is due to the extra costs associated with arranging for further simulations.
- Under the scheme, sealed unit components will be chosen by the official simulators acting on behalf of the window fabricator or supplier. This means that the sealed unit manufacture will have no control over the makeup of the unit and so will be forced to supply a product exactly to the specification (including brand naming) as dictated by the original simulation. It also means that in order to gain access to the full market, an IGU producer would have to stock every brand of component and use every different type of production method. Clearly this would be impossible.
Thermoseal Group supports the introduction of a Window Energy Rating Scheme and believes that the GGF is the best organisation to administer this scheme. However, for the scheme to work it must be fair and open. If you are concerned and would like to express your views regarding any aspects of the scheme, or if you would like some guidance and clarification of the guidelines of the scheme, we suggest you write to the following:
Nigel Rees Chief Executive
Glass and Glazing Federation/British Fenestration Rating Council
54 Ayres Street, London SE1 1EU
John Feinnes
Sustainable Buildings Division
Department of Communities and Local Government
Zone 5/E8, Eland House, Bressenden Place SW1E 5DU
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Good on you Mark , I think for clarity everyone does need to complain about the scheme, it is pretty much unworkable and ignores any issues that crop up, as the ’science’ behind the scheme doesnt stack up.
1 point I would argue Mark is your point 4 that ‘it favours window companies and fabricators’. the situation is a little perverse in this respect in that the BFRC scheme, without doubt, enables the smaller IGU makers the chance to continue to make DG units using K glass , however it does make it very difficult for them to market these units as they will have to persuade the fabricators to specify their products. Now, if the CLG where purely to specify U-values then K could soon be a defunct DG product which means that all the smaller IGU makers would have to make triple glazed units to make a unit that complies or close down.
Hi Kevin,The small IGU guys have no problems there are glasses from Guardian and AGC that they can use as well as the Pliks stuff. Even if they have to edge delete the equipment is real cheap – its more of loss to Pilks revenue! The main thing will be to promote the other rating agency if they are more flexible and the En14351 method which will be cheapest and easy route if the Window profile guys are up to speed with helping the downstream operators.
OK but would there be enough to go around ? I know you hear rumours of price cartels in the glass industry, but why haven’t he likes of SGG been voicing their concerns over the BFRC scheme, I am sure I heard somewhere that if K was no longer good enough there would not be enough better product to go around , I wouldn’t have though the scheme could be being used as some sort of market share device.
Don’t want to get too embroiled in this turf war but fair play to “Wheels” Hickox for sticking his head above the parapet. Just so you know, we do a manual edge coating deleter (BO 89.110) at just £778 vat!
Yes Dave ,but do you do something for checking deflection of glass panes?glass types? I thought you did how long does it take to get a trial on one?
Aha! Asking me a question when we are both sober…Now you will get some action! On the case…
Yup its like a flying mini except theres more technology in the mini ha ha
Dave this is not a ‘turf’ war, it is possiby the most important issue in the replacement window industry at the moment. It needs people to get involved that is the whole point of Marks post.
WINDOW ENERGY RATINGS AND THE GGF: THE FACTS
The Glass and Glazing Federation has become aware of criticism being levelled at the Window Energy Ratings scheme (WERs) and its introduction and management by the British Fenestration Rating Council (BFRC), a company within the GGF Group. The GGF believes that there has and continues to be a great deal of misinformation about WERs and the following is in response to a press release prepared and distributed to the core glazing trade press by Thermoseal Ltd. We believe that this is premature as the proposed changes to the Building Regulations, contained within Approved Document L 2010, have not yet been published and comments about its content can therefore only be speculative at this stage.
Nonetheless we believe that the industry should have a clear understanding of the position of the GGF Group in relation to WERs. Each point of the Thermoseal release is answered directly:
Since the 2006 Building Regulations update, BFRC WER has been one of several means of compliance. We are not aware of this causing any difficulty in compliance whatsoever. We strongly believe that WER will not be the only means of compliance when the latest revision to Building Regulations is available. This will be proved one way or the other with the publication of the new Building Regulations up-date – probably within one to two weeks (early April). Accordingly we suggest that readers await the facts before speculating. The logical time to have raised concerns which anyone had in this regard would have been during the extensive Conservatories and Local Government (CLG) consultation period up to September last year. Indeed we are aware of a number of organisations that responded to the consultation suggesting that more than one means of compliance should be continued.
It is a fact that BFRC is currently the only body in the UK set up to run a WER scheme. The scheme itself was developed for UK over a period from the late 1990s to the early 2000s via an extensive cross-industry study (with open consultation) involving UK government, EU funding and independent academic advice, drawing on work done and accepted internationally on the key factors in determining the whole window energy performance of a window and how they should inter-relate (i.e. the underlying whole window energy rating formula). After completion of the development phase, GGF was invited by the industry at large via the various trade associations and those most active in the development of the scheme (and with CLG’s blessing) to take on responsibility for running it around the middle of the last decade. Note: There was no right granted to change the formulations which neither GGF nor BFRC have any right to alter.
To the best of our knowledge, no other body has sought to run a WER scheme to date. However we understand that for any alternative scheme to qualify as a basis for Building Control compliance or to operate the European standardised “rainbow” energy label, it would have to be based on the same underlying formula as that is the basis the Government and EU endorsed for these purposes. We would also hope if there were any alternative schemes on this basis, that they had sound and proportionate controls to ensure a level playing field for all WER windows in the interests of the industry, of effective compliance and so as not to risk misleading the consumer.
The academic basis of the formulation developed as described above is to provide a whole window energy result, which has the obvious benefit of being what the consumer needs and wants as well as satisfying Government requirements for Part L. It is entirely logical that when a component changes, the whole window energy performance and therefore rating may change. Therefore logically there needs to be some form of vetting and control to make sure that is properly affected. BFRC does and will seek to make this as “light touch” as possible, subject to the needs of safeguarding the integrity of the scheme.
BFRC has always been keen to ensure this process is as easy and cost effective as it can, consistent with proportionate control to protect the consumer and other stakeholders. It has already developed and launched an “Authorised Retailer” scheme which gives more flexibility to installers purchasing frames from a licencee, whether glazed or unglazed, to operate a licence. It is also in the process of rolling out a new Certificate of Addition variation, which further simplifies and reduces the cost of amending components, particularly those related to the sealed unit and simplifying rules covering variations in beads. It is intended that full details will go up on the BFRC web-site and be released to trade press within the next week or so.
BFRC is also looking at the viability of building up a database of components and their individual performance with a view hopefully to further simplifying the process of both simulating additional windows for licences or checking the impact of amendments (e.g. for Certificates of Addition). However that is a process which will take time, investment and the co-operation of suppliers of the constituent parts. Therefore BFRC cannot yet predict when and in exactly what format that can be made available though it is committed to maximising flexibility subject to the constraints it has to operate within.
The whole concept of a WER is to measure the energy performance of a completed, whole window in accordance with UK and European standards and methodology and requires all components of a window to be simulated together. It is not within BFRC’s power to amend this, nor does it believe it technically right to do so. However as indicated a it is doing everything reasonably within its power to provide maximum flexibility to substitute components. BFRC currently has no knowledge of the practices suggested. To the extent that this might occur, we would expect market pressures to sort this out if the respective customers wished to purchase in a different way to that which a supplier was offering. However that is not with BFRC’s power or responsibility.
The tremendous development of higher performance energy rated windows and the components contributing to this growth over the period of BFRC’s active involvement with its scheme (and paralleled by the growth in WERs registered with BFRC) would suggest that BFRC is not a disincentive to innovation. In deed it would suggest with the whole energy debate it is a stimulus to innovation. As indicated, BFRC is actively engaged in a number of developments in the way the scheme is operated (but within the original concept) to further assist with flexibility and innovation.
However it cannot be expected to have a scheme which delivers and licenses a precisely calculated rating (and many associated benefits) run without cost and without enough checks and balances to protect the consumer. Incidentally, BFRC charges could be described as modest – and it will always seek to maintain this. Additional costs are generated for simulations or vetting processes required, but these are to separate individuals or organisations and are not income to BFRC. Many organisations (both licence-holders and component suppliers) are increasingly having their own staff accredited as simulators to assist in flexibility, cost reduction and in improving the service to their customers in an era when the energy performance of their products gets ever more demanding, whether by the consumer or by regulation, and whether for WER or other means of compliance.
It has been suggested the BFRC simulator choose the components used to the determent of some alternative components. This is not so. The customer chooses the components. He may use professional input of an accredited simulator, either independent or on his own staff, to achieve the result he wishes, but in the end the customer decides. How else can it be?
Nigel Rees GGF Chief Executive commented: %u201CThe revised Building Regulations will be published shortly and there is then a period prior to their implementation in October 2010 during which these will be assessed in depth. Perhaps then will be a more appropriate time for this type of discussion, when the full facts are known and we will see if Mr Hickox%u2019s comments will be validated. %u201C
Not diminishing the cause Kevin, just don’t feel qualified to judge the issues. That said when opposing parties communicate by press release it suggests that real dialogue has failed.
I personally believe all this talk of european methodology is all very nice , but the fact remains that when this formula was derived by Dr Robin Kent the resultant index ALWAYS produced a negative value to the index No. After the BFRC got hold of the formula it subsatntially changed . the solar gain factor increased by around 33% from the project you appear to describe. I have only had one question that I have been asking for quite some time. What is the climate reference source for the solar flux data that you use in your formula ? If you could kindly let me know then we can all evaluate the formula based on it’s scientific merits. If it is proved to be an accurrate energy balance formula ,then we can all help to make it work if it is not then we would be entitled to know why the scheme exists.
After all it is the BFRC ‘limitations to use’ that tells us the formula is NOT an accurate energy balance formula. please refer to My GGP article in March edition. I believe that there are significant issues with the implementation of the scheme, but that they all boil down to the exagerrated solar gain in the formula.
One sentence from you may clear the whole thing up , the climate reference source for the solar flux data that you use in your formula .
Kevin, I can assure you that the formula has NOT changed since BFRC Ltd was established in June 2006. The constants have remained the same which would impact on the solar gain factor. Hope this helps?
In that case would you mind explaining whothe custodian of the formula was in 2003, date of publication of the ‘derivation of the A and B constants’, Bearing in mind, of course, that the BFRC logo is all over the 2003 document. Or is the 2006 date your trump card and you will wash your hands of all that went before.
Another very large sealant company has now joined the ranks of people threatening to sue the BFRC over the incorrect sealant values used in simulations – full technical details have been presented to Giles etc but as usual no response simialr to when i and others in a working group informed them.They have known this is wrong for months loads of A ratings out there are actually B ratings! I will publish to the whole document trail with minutes of meetings etc unless Giles would like to call me to discuss!?
regards Mark
I’m Glad we have been patient, and haven’t spent ££££’s yet.
Sorry I do not understand you comment Kevin. I have just looked at the BFRC report “Deriving A and B factors for the UK climate” dated 22 September 2003. The constants are A = 218.6 and B 68.5.
These are the constants the BFRC scheme use today. So nothing has changed.
Put simply Giles , that report does NOT state the reference source for the climate data that it uses to create the 218.6 solar factor.
question 1 can you identify that reference source please.
May I quote from Dr Robin Kent, which is likely the result of the government funded, academia and peer review process, that you eluded to in your original answer.
http://www.tangram.co.uk/TI-Glazing-Energy_Rating_for_Facades.html
Paper presented at ‘The whole life performance of facades’ conference at CWCT, Bath 18 April 2001.
From which I will quote ..
“The British Fenestration Rating Council (BFRC) has produced a Domestic Window Energy Rating Scheme (DWER) to produce a single rating number for window energy efficiency.
The rating number is calculated from the individual values of the major energy transfer mechanisms. These are:
1. The U-value, which measures the overall window U-value and not just the glass component.
2. Solar heat gain coefficient (g), which measures how well a product transmits solar radiation and is a number between 0 and 1. A lower g means less solar heat gain.
3. Air Infiltration (L50), which measures air leakage through the window when it is closed.
These values are applied via the formula:
DWER = (25.9g – 11U – 0.12L50) + 74 (1)
where the correction factor 74 is used to produce a rating number from 1 to 100 for ease of understanding by consumers.”
Now, we see that the BFRC has produced this formula, and while it is produced in a different scale, it is the ratio of gain to heat loss that interests us.
Formula ratios , original formula 25.9 / 11 = 2.35
2003 formula 218.6 / 68.5 = 3.2
So we can see that in 2003, the government funded, academia etc etc etc formula was re written and presented with 36% higher solar gain ratio.
Hence my question, can you identify that reference source of the climate data that was used to re write the formula please?
I have to say , I have just had a thought that you may not be familiar with this work, or the alterations I report , but from the lack of help from some at your organization I was presuming that you (BFRC) were just trying to ignore me and suppress the information. So please forgive me, if I have come across a little ‘forceful’.
I hope this helps to clarify my position and has not confused you further, but just to clarify.. can you identify that reference source of the climate data that was used to re write the formula in 2003 please?
Kevin ……. WOW
Giles ….. I’m interested in the answer.
Matthew …. We’ve got to get these guys on the couch and sell Sky Box Office tickets too!!!!
All proceeds can go towards the hospitilisation of one or the other on them..
I have been reading with some interest this and the Thermoseal blogs and I feel it timely to try and summarise the contributions from these sites and the feelings within the industry. I would like to make the following observations
Almost without exception everyone agrees that the Window Energy Rating system is an excellent way of differentiating between windows of all types and with the Government wanting to reduce our carbon footprint, it allows the industry to make a valuable contribution to this target. However, the complicated nature of the scheme and intransigence of the BFRC to embrace simple, logical and sensible suggestions has lead to at least five major “players” in the industry threatening to take legal action.
My perceived problems with the scheme – in no particular order:-
1.The majority of the Directors of the BFRC have admitted that they don’t really understand the principles of the simulation process and those who do, it could be argued, may have commercial reasons for not wanting changes to the scheme.
2.The BFRC do not understand how the window industry functions. One example that came to light well over a year ago was that they assumed that the fabricators always supply fully glazed windows – being totally unaware that most installers prefer to purchase sealed units from their local suppliers who provide the level of service they require. There are numerous other examples that confirm my opinion.
3.Their knee jerk responses to problems that have arisen confirm this ignorance.
a.The installers or Approved Retailers Scheme – Is expensive and virtually impossible to control (audit) properly with the scheme in its present form. Perhaps this is why there has been an extremely limited up take and is not recommended by consultants and some Independent Agencies (IA’s). All an installer wishes to do is to be able to buy their compliant units from their preferred supplier and match them with the frame that they buy. This is relatively easy to accomplish and a simple “paper trail” could provide the necessary evidence for any auditor to confirm full compliance.
b.The Multiple Label Scheme. On the face of it, this is a good idea but auditors and IA’s have informed me that it is a time consuming process to audit (expensive) and the chance of windows going out incorrectly labelled increases exponentially with the increase in label numbers. The cost appears to be low but the sting in the tail is that simulations in the fabricators name (or cascaded from the profile supplier) have to be available for the IA’s to inspect and this leads to hidden expense!
4.These schemes have all been introduced without consulting the industry experts and representative bodies. They have not been and probably will not ever be embraced by the industry enthusiastically.
5.The BFRC scheme is claimed to be “very robust”. I would agree that the simulation process is certainly robust, perhaps to the point of being proscriptive and restrictive and maybe this is the reason for the recent threats of legal action. However, after this robust process the whole system breaks down because.
a.There is no rule book for the Independent Agencies (IA’s) to work to
b.The IA’s do not have the auditors with the necessary experience to adequately “police” the scheme.
c.The fabricators do not have to have the robust scheme the IGU Manufacturers are forced to comply with. Although the fabricators are cascading EN Test results down from their profile suppliers they are not required to have a quality system in place to ensure that the frames made conform to those tested. i.e They do not have to prove their frames are fit for purpose.
d.The whole scheme appears to be open to abuse and “cooking of the books” has been noted but not exposed officially.
6.It is a common misconception that A Rated windows relate to quality – this is not the case and the scheme only relates to the thermal efficiency of the product when it leaves the factory fully glazed – there lies another anomaly within the scheme!
7.The BFRC have ignored advice given relating to the thermal properties of sealant used in the construction of double glazed sealed units and other components. This is symptomatic of their arrogance and ignorance and will probably come back to bite them in a way that may well threaten their future as a force within the industry. However, it will probably leave the door open to alternative schemes!
8.The BFRC have apparently sought clarification of the thermal properties from certain component manufacturers but have not been so even handed with others.
9.Substitution of components of equivalent or better value is a principle that most quality standards embrace. Until recently the BFRC has been intransigent on allowing this. However, when pushed by major players, they have allowed a number of exceptions i.e. The substitution of beads of a better value and the substitution of a major glass suppliers new glass that has better values. That is good step to make but why only for these products and not for others?
10.In simulations there is an insistence to “name” products – surely the use of their values would enable a simple substitution system and encourage new products to come to market?
11.Manipulation of Simulations – Many suppliers to the industry have openly admitted that they manipulate simulations to provide the best rating possible. Although this is understandable it is in the following examples a recipe for a repeat of the wholesale unit failures experienced in the late 1980’s.
a.Depth of seal – The depth of seal over the back of the spacer bar has been reduced to a level that effectively brings the spacer further down in the glazing rebate – Improving the thermal efficiency of the window. However, this means that the IGU manufacturer is making units that are outside the sealant suppliers’ recommendations and is taking the risk that they will fail prematurely. Assuming it is possible to make units consistently to this specification, I doubt if the manufacturer has had units of this configuration tested to EN 1279 Parts 2 and 3. Modifying their System Description to include these low parameters as their minimum depth should result in IA’s rejecting any units found to have sealant depths above this minimum depth claimed. Incidentally it will be the company putting the product to market that will be the one liable – The Installer!
b.Clearance around the unit: It is common practice to deduct 5mm off the window size to provide adequate clearance around the IGU for glazing purposes. Some simulations have been “adjusted” to only deduct 3 mm from the tight size, again improving the BFRC WER Rating. It is obvious that glazing into a fixed opening using this configuration is perhaps possible but impossible to “toe & heel” a unit into an opener. Even if glazing was possible the 3mm clearance in the glazing channel would not allow adequate drainage as the surface tension of water would result in the water being trapped between the unit and the frame!
Effectively these manipulations will result in lower life expectancy of the IGU’s and this will be exacerbated by the units sitting in water. What effect on the “Carbon Footprint” will all these failures give?
12.FENSA – yet another body owned by the GGF. What (and how) will they be looking for when inspecting windows for compliance to the new regulations? Perhaps this subject can be debated on this site as at present there is, for one example, no way of ascertaining what type of glass (exact coating or glass type) has been used within the IGU!
13.EN 14351. There has been some debate within the industry as to whether this European Standard is mandatory or not. Perhaps it is an irrelevant question as the change of the CPD to the CPR, which will occur in the next few years, will once and for all answer the question. However, the frame manufacturers must have a quality system in place that proves they are making their frames exactly to the profile manufacturers’ recommendations. After all they are using (cascading) test data that has been conducted to a European Standard by a notified body test house and as such they need to prove they emulate the windows tested!
Might I be so bold to suggest to Giles Willson and his colleagues that, rather than just announce changes to their scheme that may be totally unworkable, they come up with some suggestions and then use the expertise within the industry to establish if they are viable.
To name but a few that are eminently qualified and almost certainly willing to assist are:-
Mark Hickox – Thermoseal. Component Supplier
Gaby Mendham – Ecoglass. IGU Manufacturer
Richard Bate – Build Check Ltd. Simulator and IA
Mike Gaillard – CENSolutions Ltd. Auditor and Consultant
Richard Sellman – HB Fuller. Sealant and GGF IGU Component Group Chairman
Andy Jones – Edgetech. Organic Spacer supplier.
And a glass expert representing all the glass suppliers.
May I put my hand up to be the exception on this one please, I do not believe that the WER scheme is an excellent way of differentiating between products at all.
All the amending and adjusting and sitting down with as many professionals as you like, will NOT put this scheme right . It is fundamentally flawed, the science is wrong, whether that was by accident or by design only one or two people will ever be able to comment. I do however have my own thoughts on that issue.
The Document that Giles refers to “BFRC report “Deriving A and B factors for the UK climate” dated 22 September 2003 “ is no more than a smokescreen that pretends to offer a scientific approach , while taking the “baffle with bulls**t” approach
I view with concern all the problems and costs incurred trying to implement this scheme, however the science needs putting right first. It seems to me a bit like an industry currently chasing rainbows!
As I referred to earlier , as the BFRC might not actually realise what they got lumbered with , it might be prudent to research their own product a little further, OK may the horse has already run away but the stable door still needs shutting !
I don’t think I will get an answer to the reference source of the solar flux data , I never did to be honest, but it is still worth asking .
[...] following text I found on the GlassTalk blog and felt it deserved sharing [...]
FAO Kevin
You might want to have a read of a 1999 paper by Oreszczyn, Lowe & Oliver for the BFRC entitled ‘Domestic Window Energy Rating (DWER) & Revisions to Part L of the Building Regulations’. This very interesting document proposed a methodology for deriving a UK window energy balence equation in Appendix A.
Mind you this was back when the BFRC was being run on a shoestring before a rather large glass manufacturer got involved.
My own thoughts;
1.The BFRC rating was explicitly only ever intended for replacement windows.
2. A south facing window is obviously going to have a completely diiferent energy balance to a north facing window.
3. The Swedish rating system should have been implemented. U-value, ‘g’ value & air leakage rate. No ‘magic dust’ sprinkled over the level 1 data.
4. Unfortunately the barrier was set to low as evidenced by the flood of A rated products. A window with a u-value of 1.6w/m2k is hardly going to work in a ‘Passive’ level building.
4. The scheme for all its faults has been a success in reaching the consumer and raising awareness of energy loss. Robin Kent deserves huge credit and a Knighthood or similar.
I am very aware of the paper you describe and it was presented as an investigation as to the viabilty of such a scheme.
Further work was done by Robin Kent as I referred to earlier, but his original formula which was produced for the industry ( as BFRC) showed a significantly lower solar gain factor than his own re-written formula in 2003.
Monty maybe you could explain that fact , maybe you could tell me where the solar data came from , maybe you could explain the relevance of the ” Dutch reference building ” in the document that purports to explain his formula.
I have tried to contact Robin Kent with these questions but alas no response . The idea of a scheme has some merit , and was probably started with the best intentions , however , if it is not right, no amount of pretending it is, will make it so.
Everyone keeps telling me the scheme is for comparison use only , but has anyone explained to a customer that the only difference/comparison between his existing windows and his proposed new windows is it’s insulation value?
I think most customers are aware that on the basis of energy loss , windows are not exactly the first choice for home insulation, based on return of cost.
The scheme is 1 big fault .
Mony , apologies , It was a paper by Oreszczyn, Lowe & Robinson on the topic that I am familiar with. Is the paper you refer to available? Does this paper explain the solar data ?