/ Home & Energy

Need new double glazing? Who would you trust to install it?

Only 7% of Which? members trust double glazing companies. Not that surprising when they’re renowned for dubious selling techniques, and steep price drops are a familiar part of the sales patter.

But building regulations mean we don’t really have a choice but to install double glazing when windows need replacing.

So when you’re shopping for new windows, should you trust the big names like Anglian and Everest, or should you go for a smaller, less well-known local firm?

Independent double glazers do better

Our latest satisfaction survey of double glazing companies found that that independent traders perform better and might even be cheaper.

The four big national companies (Anglian, Everest, Safestyle and Zenith Staybrite) are apparently leaving customers less satisfied than those who went with an independent double glazing company. As one Which? member said:

โ€˜Local firms rely on word of mouth for their reputation and in a small town they cannot afford to let this slip.โ€™

Local firms could be cheaper too

And, while you might assume you could get a better deal using a large firm, that’s not necessarily the case.

Weย sent a price questionnaire to Which? Local recommended double glazing traders to get the average prices you should expect to pay for different double glazing jobs.

We also sent the same questionnaire to Anglian, Everest, Safestyle and Zenith Staybrite. Both Everest and Safestyle declined to share their prices, with Everest telling us, โ€˜Itโ€™s no secret that we charge a premium price for our productsโ€™.

Anglian and Zenith both provided their prices, but we found that these were typically higher than those quoted by the independent traders who responded.

Problems getting double glazing

Whatโ€™s more, those using local independents are also less likely to experience problems. Of those members who used local firms, around two thirds didnโ€™t have a problem. But this figure fell to just over half for those who went with one of the big four companies.

The most common problems were: delivering the wrong parts, scratched glass, windows not fitting properly, installation taking longer than planned and installers causing damage to a propertyโ€™s interior. Each of these problems were nearly always more common with the big four.

So, if you’re planning to get new double glazing, will our research influence whether you go for an independent or a big name? And if you’ve recently had windows fitted, who did you go with and how did they do?

greg ferguson says:
25 January 2013

avoid sovereign windows of sawbridgeworth and a&a windows direct of harlow, they do shoddy work and were abusive when asked to correct it, also said we damaged the windows ourselves the case continues

Myrtle123 says:
22 March 2013

We used Anglian over a year ago to replace our windows… I think whether or not you have a good/bad/indifferent experience with them is very dependent on the salesperson, the surveyor and the contracted fitter.

We have been really pleased with our windows… The salesperson wasn’t pushy and cut to the chase quickly. They offered us a good competitive price and the windows were far better quality than any other local firms we looked at, and the contractors worked so hard to fit them well. I could have done without the standard sales patter but was expecting it to come so zoned out for that bit and there were issues with the surveyor’s measurements but the contractors called their manager out and the issue was resolved quickly and efficiently and the windows look great.

Like most things in life it comes down to the individuals involved and with larger firms the probability is greater that you will end up with a turnip.

Michael Tripp says:
9 June 2013

[This comment has been removed due to being a duplicate. Please use only one username. Thanks, mods.]

Peter Johnson says:
9 June 2013

I have used two local firms to do work on my home and I have been very disappointed. So I did my homework and investigated why they always do such a poor job. Because there are so many local firms they can only compete on price. By competing on price they cut corners all the time. They use less of a material they always by in from larger companies. So they may claim to be as good as others but the generally use what other companies use. A lot of the time like what happened to me the guarantees aren’t written the paper they are wrote on. Insurance backed warranties aren’t good when the company goes bust. And then sets back up again in the wifes name as I later found out. If you want your home improved to a tested standard use a national company I wish I did. There is no such thing as local anymore anyways. What country is your car from? Where does a lot of your food, clothes, technology, furniture come from? Only a small percent comes from this country.

Michael Tripp and Peter Johnson have reported very similar experiences. ๐Ÿ™‚

Colin Samson says:
9 June 2013

Yes, obviously the SAME PERSON submitting the SAME COMMENTS TWICE under different names.

Amy Hanlon says:
14 July 2013

I would always pick a local small company over a huge company charging over the top rates! I used a local firm called rab windows & I still got a 10 year guarantee.My family have used Everest & found problems when calling them back to repair! They are quick to fit windows but not so quick to sort any problems out! Always pick a local firm but look for genuine references/reviews.Find one very near to your home too.

Diane says:
28 July 2013


So I wanted a small glass extension to my kitchen. Quality and customer service are important to me so I went to Everest as one of the bigger firms. It was a total mistake.

The salesperson didn’t show up for the first appointment despite my taking time off work. The next one lied to me from beginning to end. He told me I would not need planning permission. I did. He gave me a written finish date. They started work 4 months later than the promised finish date. When they finally showed up to start they had not ordered the required street permits which I had told them they would need – so they had to delay.

They did not inform me of the base drying time of 70 days. They manufactured the doors to open the wrong way. When they finished the work the conservatory leaked in 2 places. And now the grey aluminium window in the roof appears to be melting to reveal white underneath.

The warranty which should have arrived within 10 days of final payment still hasn’t arrived 2 months later.


Jan P says:
7 August 2013

After poor experiences using well-known national companies to install bathrooms and a kitchen, I decided to approach Rated People.com when I wanted to replace all of the doors and windows in my house. I was aware that Which? had found greater customer satisfaction when people used small, local companies that depend on their reputation to generate business. I thought I had found a reliable firm, which described itself as ‘one of the good guys’. I was happy with their quotation and looked at an example of their work. The survey was done in June and then – nothing! The company do not respond to messages of any kind and Rated People.com have also been unable to establish contact. Thankfully I did not part with any money. At least a large, national company is likely to have a local showroom that you have access to.

I think the problem with sites like Rated People, is what they don’t say. It is quite possible to tick all the boxes and write a very short comment that does not reflect the actual company and work done.
After an experience a few years ago, I would not touch any company that had very short comments but choose one with longer comments that reflected extra work, good communication or went out of their way to complete the job.

Agreed, However, the internet is a pretty poor place to get trustworthy information. There is little control and authentication done of what people post and in the case of double glazing many (some would say most) of the negative comments are posted by competitors of the company being criticised! (And it doesn’t just apply to the windows industry). Add to that the fact that if people have a bad experience they’ll complain. Whereas they’d have once written a letter to Esther Rantzen in the hope of it being broadcast on Sunday night TV to bring the company to it’s knees, now they create a fuss in a few on-line forums determined that the company that has wronged them in some way will forever be damned and put out of business – even when it’s down to one person in that company making a mistake or being lazy or whatever. Not inherent skullduggery in the company.

Few who have a good experience take the time to post a positive report. The internet is good for a lot of things, but in the real world, doing some due diligence on a purchase (whether it’s a car, TV, Hi-Fi, or windows) to understand what is important to think about in the product’s construction and performance, efficiency, durability etc is important. People buy windows and doors with little thought to what they will look like (in relation to the original architect’s designs for the house/flat etc), how they will perform over time (and what affects their life-span), whether they will have adequate ventilation options, etc. They may have some cursory interest in security but often make choices in blind ignorance of other important aspects, based on price alone. It’s amazing that people so easily spend thousands of pounds without truly understanding and appreciating what they compromise upon – until it’s too late and they are faced with replacing the windows again or getting sealed units replaced or having some other kind of maintenance done on them.

As has been said already in this thread – if you buy a TRUE quality product (and the only way to assess that is to find out what makes a quality window or door (and not just because the salesperson says so – understand exactly WHY before you decide!), from a reputable supplier that is financially sound and will be around to stand behind its guarantees; then you are likely to be able to forget them for at least 35-40 years (and by then I think any reason to change them would be because the technology has moved on or one simply wants a change in style rather than because they are a problem). Or we need armour plated windows to protect us from the undoubted anarchy that lies in the future…. ๐Ÿ˜‰ .

But he who believes everything they read on the internet (unless it’s by me, of course…) is also likely to believe in fairies, the Easter Bunny and that Nottingham Forest will win the Champions League one day… ๐Ÿ™‚ People put time and effort into choosing so many other significant purchases or important services and researching the pros and cons, features and benefits, whether it’s a house, a car or a holiday, a TV, a three piece suite, a school, a mobile phone contract…How many of those are ever made upon a price point? (within reasonable budget range, I mean – no point in looking at ยฃ1m houses if you can only afford ยฃ100k – but perfectly adequate houses are out there for ยฃ100k so you buy the best you can at that range ) with windows and doors something half the price of the most expensive is going to be missing a lot of things that make spending double a better purchase in the long term. And anyone who thinks otherwise is stupid, frankly. But if one can only afford the cheap windows then buy them knowing that you’ll have to find the money to do the job again in the medium term. But buy with the knowledge that complaining about having to buy again in 10-15 years isn’t going to get you anywhere. If you truly understand the difference between the cheap window or door and the premium one, and can afford it, then invest with confidence and know that it was an exactly that, an investment, not a cost.

Maybell says:
8 September 2013

I installed triple glazing in my house in 1985/86. I was told I was mad at the time for paying the 10% extra it cost over double glazing. The only windows I get condensation on are my patio doors.

Laurie-Anne says:
3 October 2013

I’ve just had double glazing installed on Monday and three of the windows have obvious scratches visible from more than 3 mfrs with the naked eye. I wasn’t happy so only paid half of the total cost.. now they are coming to change the glass in these 3 windows today! I don’t really understand this as I thought they were factory sealed units therefore won’t this invalidate the sealed bit? I’m a pensioner and not really sure of my rights but I stumbled on your discussion while trying to find an answer. Can anyone advise please?

I expect that they will change the sealed units. These have to be made up, so they could not do this at the time of inspection.


Don’t worry. The ‘sealed unit’ refers to the two panes of glass which are bonded to the spacer bar all the way round and then (after the air between the panes has been replaced with argon gas) sealed. The finished sealed unit is then fitted into the frame. So replacing one with scratches just involves removing the damaged sealed unit and putting in one to replace it. Sealed units are sometimes fitted into the frames on site (rather than at the factory) especially if they are large and heavy, so don’t be alarmed. Provided you are with a reputable firm and they take care in removing the beading and replacing it, then the windows will look as good as new and perform as well as if they had left the factory that way. It’s unfortunate the original windows were scratched, but accidents happen when a window is transported from factory to perhaps a local depot or shop, then to site and then installed. So the company appear to be dong things right. In fact to be able to replace the sealed units so quickly is amazing. Most good companies would want to make things right quickly (and you are right to have withheld final payment) both to make you happy and to collect their money – but a three day turnaround is very good.

Colin Samson says:
3 October 2013

Good comment. However, I have been selling double glazed & triple glazed windows since 1981 and have only ONCE sold argon gas filled sealed units! Nearly all sealed units are still air filled with dessicants (such as silica gel) inside the spacer bars. The spacer bars have tiny perforations in them that draw any moisture out of the air. Any moisture then remains in the dessicant indefinitely, ensuring no condensation forms inside the sealed unit, on the glass.

Argon gas does improve the insulation of sealed units, though it does slowly leak out of the sealed units and up to half of it can be gone after ten years. I do try to persuade people to invest in the very best insulation but unfortunately they rarely want to pay the extra cost involved. The best sealed units are now TRIPLE glazed (about 36mm wide overall), with two panes of energy saving (low emissivity) glass, insulated (non aluminium) spacer bars AND argon gas filled. A “U” value of 0.5 (in the centre of the sealed unit) is now possible; that is more than eleven times better than single glazing!

I suppose it depends upon who makes the sealed units! ๐Ÿ™‚

Ours are made in our own factory and are guaranteed for 15 years, but in reality will probably last 3 or four times that amount. Argon is a far better insulator than air which is why most competitors I have ever come across offer it as standard. I’m surprised that you advocate air filled – and silica gel which is not a particularly safe material to have around, though I concede that inside a sealed unit it is pretty safe – unless the unit gets broken. As for triple glazing, the temperatures in the UK don’t warrant the additional expense – think about it; whether you are comparing the quality end of the market or the bucket-shop windows, on a like for like basis, the windows have 50% more glass in them; need additional strength to the frames; are heavier and put more stress on the hinges and frames; cost more to manufacture, to transport etc. The cost and selling price premium doesn’t justify the potential savings. Triple glazing is beneficial in places where temperatures drop regularly below -10 or -20 etc. In other words Scandinavia, Russia..Where I’ve spent a good deal of time and know what a GOOD triple glazed window is. Here, it’s only attraction is if money is no object (I’ll have a few of those customers, please!) or want to be ‘ahead of the Jones’… ๐Ÿ™‚ I’d not recommend triple glazing to anyone in the UK. They are better off putting in an A grade double glazed unit on southerly facing windows and putting the savings in the bank.

Colin Samson says:
3 October 2013

I DON’T “advocate air filled sealed units”. However Argon’s effects on insulation in a 28mm Low “E” Glass sealed unit is quite small for the extra cost involved. Such an air filled sealed unit with a “U” value of 1.5, will have this reduced to 1.3 with Argon gas; an improvement of only 13% at an extra cost of between ยฃ8 – ยฃ10 per square metre extra retail (the last time I looked). Personally, even though I now have a very small income, I would not even consider less than triple glazing with double low “E” glass if I were to replace my windows again. Just because it may not make a lot of economic sense now, does not mean that it won’t in a few years’ time, as energy costs show no sign of racing ahead of general inflation & peoples’ pay packets. Of course triple glazing also noticeably improves sound insulation (our customers now demand it on a certain apartments complex that faces onto a main road in Bristol) as well as further minimising the risk of room side condensation. Most of our North Somerset competitors are now selling products with triple glazing as standard.

Colin Samson says:
3 October 2013

I MEANT to say: . . . as energy costs show no sign of STOPPING racing ahead of general inflation & peoplesโ€™ pay packets.

Colin Samson says:
3 October 2013

You will discover that they will replace the complete sealed units by merely removing the (PVCu?) beading on the inside of the frames. The two panes of glass will be bonded to a spacer bar (usually about 20mm wide, giving a 28mm overall sealed unit width), so the whole sealed units will be removed & replaced as if they were one thick piece of glass. Your guarantee will not be affected and the new sealed units should be just as good as the original ones, but without the scratches (I hope). As soon as you get a bright, sunny day, inspect the new sealed units again, as scratches might not show up in dull light or if it is raining. Unfortunately, scratched sealed units are quite common, due to sloppy handling of them between the factory and your home. GOOD LUCK!

Londoner wrote: ‘Argon is a far better insulator than air …’

I would be grateful for figures to back up this statement, which I find surprising.

Colin Samson says:
3 October 2013

You are correct, Argon Gas typically improves the insulation of a double glazing sealed unit by about 13% only. Quite meagre for the extra cost & dearer than upgrading to triple glazing!

Argon has a thermal conductivity 67% that of air. You can Google it if you doubt me.

Therefore it would not be correct to say that argon is a ‘far better’ insulator than air. ๐Ÿ™

Argon is not expensive either, so there is certainly no reason for a substantial extra cost for units containing argon.

Um, the difference is 33%. And the relatively minor cost of argon (once you have the equipment to inject it) is a fraction of the cost of 50% more glass, and probably 50% more of anything else that goes into making and sealing a triple glazed window.

If it made no sense to put in Argon, why do the majority of fabricators and manufacturers choose to do so? The justification for argon (or any other inert and similarly better insulator) was made a long time ago.

My guess is that the main reason for offering argon is that it provides an opportunity to charge more, a bit like putting nitrogen instead of air in tyres.

But no doubt the brochures all explain that argon is not, in fact, a much better insulator than air.

I have nothing against those in the double glazing industry but I loathe the general misrepresentation found in advertising and descriptions of products and services.

And who says there is a ‘substantial extra cost’ for argon@ I am not aware that anyone justifies a premium solely on the gas fill. Of course it makes a difference to the product cost and therefore is marked up proportionately, but when it more then recoups the cost over a short period in improved insulation then it’s a non-issue.

The overwhelming majority of replacement window companies supply argon filled sealed units. It’s not a gimmick. It’s a product benefit. But if you are happy to sell air filled units, good luck to you, to be honest, most customers know very little about window construction when they look to buy – but if they do they ask two questions 1) are the windows internally beaded and 2) do you have argon between the panes? There are good reasons for both those questions.

>My guess is that the main reason for offering argon is that it provides an opportunity to charge >more, a bit like putting nitrogen instead of air in tyres.

Well the guess is wrong, I am afraid. Both examples provide benefits, but both have additional costs to supply them. An educated customer can decide whether the benefit is something they want to pay a little more for (me, I wouldn’t pay for nitrogen in my tyres when I consider all the pros and cons, but I would always want argon between my window panes – all things considered. And knowing how little it actually represents of the overall cost of the window

> But no doubt the brochures all explain that argon is not, in fact, a much better insulator than air.
Why would they do that? It IS a much better insulator than air.

The reason argon is a better fill between the panes has to do with the laws of thermal conductivity, – the heat transport property of the material. Thermal conductivity provides an indication of the rate at which energy is transferred by the diffusion process. For example, at one extent of the range solid, pure metals, like silver and aluminum, are very good conductors of heat, with high thermal conductivities; but gases have low thermal conductivities and, therefore, don’t conduct heat well. As far as the Argon vs air question is concerned , Argon (as do most monatomic gases) has a very low thermal conductivity when compared to air, and is, therefore, a better insulator. Full stop. Scientific fact that you’ll find plenty of evidence for in physics and chemistry textbooks and all over the internet.

> I have nothing against those in the double glazing industry
How awfully good of you. Why on earth would you have anything against professional experts in their field? ๐Ÿ™‚

> but I loathe the general ?misrepresentation found in advertising and descriptions of products and services.

It’s called ‘Marketing’ and exists in every market and industry. And as in any industry there is ‘marketing’ that is informative and educational, factual, useful, influential and stands up to examination, questioning and challenge. And there is ‘marketing’ which is at best ‘fluff’ and at worst CAN be misleading, boasting based upon nothing but an opinion, and in the worst cases downright lies. (and in those instances there is legislation and the Office of Fair Trading to turn to if you become a victim).

But as I said, that’s a phenomenon in any market or industry. Caveat Emptor applies everywhere. If making a substantial purchase of anything – a car, boat, holiday, kitchen, bed, suite,… it is good sense to do a bit of research before going to the market to establish what features are important and why and then test the suppliers you shortlist to see if their claims match up with reality. Do you believe the MPG figures in car brochures? The return on investment in solar panels or stock market investments? The amount you’ll get back from mis-sold PPI or that accident claim you really should have made? The number of women you’ll attract by wearing a particular aftershave or pair of sunglasses?? ๐Ÿ™‚ Of course not. But it’s all marketing. And in some cases, some of it will be true and achievable – we all need to read, consider, question and decide what we believe to be sound facts.

We did not cover laws of thermal conductivity when I did my chemistry degree. I would be interested to know why argon is chosen as a filling gas when carbon dioxide has a slightly lower thermal conductivity and is even cheaper.

One of the main reasons that I frequent this site is because of the deceit and misrepresentation in marketing of products and services in general. If I had my way, caveat emptor would be unnecessary and the consumer would be treated honestly at all times.

I don’t have a degree in chemistry or physics, but I have an enquiring mind and like to know what I am selling and why. So I listen to the product managers and engineers, more than I do to marketeers.. ๐Ÿ™‚

Other types of gases are used (for example, sulphur hexafluoride and carbon dioxide) but mainly to reduce sound transmission and it’s more commonly used in commercial buildings for some reason, but these gases do not offer the thermal performance of argon – why, I don’t know. Maybe there are health reasons for preferring argon? There must be a good reason but I confess I don’t know what it is. I’ll try to find out. If window companies wanted to just simply charge more for the gas fill, they’d use Krypton which is even more effective at reducing heat loss, but is roughly 200 times more expensive than argon per unit volume. I am told by a Canadian friend (where winters are extreme) that because krypton works best with smaller pane spacings (8 mm), it is often used in triple and quadruple-glazed windows to minimize the overall thickness of the unit. But the economics of using krypton in the UK climate and in double glazed units don’t really stack up.

As to your reasons for coming to this site – I don’t disagree with you too much, in principle. But how far would you take your ideal scenario? Should an advertiser (let’s for the hell of it say Cadbury) put out an advert that says “delicious chocolate made from a glass and a half of milk, which may cause you to put on weight, have spots, cause your teeth to rot and melt on your trousers’…? I jest, but to illustrate a point. All of that statement is true to some people. Some of the statement is true to at least some people. But who on earth would promote their product that way and who would expect it to be promoted that way? No one.

As consumers of anything we are protected by the Advertising Standards Authority. It isn’t just consumers caught out by companies who complain about them, it is that company’s competitors who complain when they make claims that are not substantially correct.. There are organisations like the Consumer Association, Watchdog and various other TV shows; there are ombudsmen, trade bodies. In this day and age it’s difficult to get away with any claim in advertising, in brochures etc that are deceitful. The worst one can get away with is a claim to be a ‘market leader’ it seems to me – now that claim is often arguably misleading. How do you define ‘market leading’..? Most items sold? Highest sales? in this country, or Europe-wide or worldwide? Leading through innovation? Leading through customer service? Other business practices??

We all present what we have to offer in the best light possible – does your CV tell people EVERYTHING about you? Or just the things that make you appear to be the perfect employee? When you want or wanted to date a girl (or a man – I don’t know your gender or preference) do you present yourself ‘warts and all’. I very much doubt it – and if you say you do then I’ll be looking for ‘consummate liar’ in your profile! ๐Ÿ™‚

No one wants to be misled – but these days there is no easy way for any of us to BE misled by anyone – the internet puts consumer research at our fingertips (not that the internet is always the source of truth and light – but it is easy to get at). Scams and the like are made public very quickly. We’ve never been so better educated about just about anything – I don’t mean scholastically educated, per se, but in terms of what we can find out about a particular product sector in general, and then in detailed specifics about the product sector we are interested in.

Salespeople will want to sell you their product. It’s their job. They don’t want to concede, generally, that their product is less good, less attractive, less of a good investment than another company’s. So caveat emptor applies to everything – companies with good products, good brand values, satisfied customers will be there in just about every sector there is – OK in some new sectors, e.g. solar energy, at the start it’s hard to figure out which of the new market early entrants are going to be the ones that build good brand values; so caveat emptor particularly applies there. But in general it has to do so. Example – Mercedes has a reputation for excellence in all respects that you’d measure that in a motor car, yes? Yet there was a period when their standards dropped, reliability wasn’t so good. And they hit the headlines frequently. Yet some people still blindly went out and bought Mercs because they were Mercs. Did Mercedes change its brochures to reflect their lapse in standards? No. Because to do so would have spelled doom. They put the things right and rightly enjoy their reputation back again now. But if I went out to buy one today, I’d be looking to see what I could find out about whether they were slipping again. Did anyone expect to buy horsemeat in Tesco…? So caveat emptor ought to be everyone’s watch word. And the bigger the purchase the more one should take the trouble to research. And that doesn’t mean believing everything the Consumer’s Association says, either – I take great issue with some of the things that they’ve recommended over the years – including in the start of this very thread…! (I wonder how the pensioner got on with her replaced sealed units today, by the way..? ๐Ÿ™‚ )

If you expect every company in every industry to tell you where they or the products aren’t as good as others, it won’t ever happen. If you genuinely feel you’ve been lied to in marketing or a sales pitch, then the ASA is there for you. I have no idea what you do for a living – at a guess I’d say you are engineer or technical person of some kind, or an accountant? (Just for the hell of a guess and for fun – how close am I?) The reason I ask is whether you’d expect your company/profession to be totally open about the pros and cons of your products or services?

The double glazing industry has some murky parts and is often castigated quite rightly – but it’s not all staffed by conmen, crooks and people after a fast buck. There are companies with a superb product range and verifiable advantages over others. That won’t let you down and won’t sell you ‘vapourware’. Personally, I try to be professional, honest, ethical, and helpful to people – many of whom are surprisingly ignorant about what they ought to be considering when replacing windows and doors – their only yardstick being ‘how much will it cost?’. You get what you pay for in EVERY industry. The trouble with windows is that unlike say, kitchens or bathrooms, people don’t think about them everyday, when cooking or bathing in them, when visiting friend’s homes, when admiring their different shapes, sizes and variations of features. So they are better prepared to buy a fitted kitchen or bathroom than they are windows and they regard it as a more personal purchase – when I’d argue that you can’t get more personal than buying products that can help keep you and your family safe and secure, provide the amenity of light and ventilation, enhance the appearance of your home and keep you warmer and save on your heating costs. But that’s just me. ๐Ÿ™‚ Time to put my soapbox away and go to bed. ๐Ÿ™‚

I had not realised that sulphur hexafluoride is used in double glazing. It’s a highly potent ‘greenhouse gas’, which may be a factor in why it is not used in domestic installations.

I’m a scientist who retired early, and I’m a bit fussy about accurate information. For example, I would say that the insulation offered by an argon-filled double-glazed panel offered a modest improvement over one filled with air, or quote figures. I tend to question commonly held beliefs. You suggest that Mercedes cars are reliable, but I’m not sure that this is the case โ€“ I would check the information on the Which? website. And as far as Cadbury’s chocolate goes, why waste money advertising when we would probably still buy too much of the stuff if it was just put on the shelves in shops?

I was once a little cruel to a pushy sales rep offering double glazing and other forms of insulation when he told me that I was losing 80% of the heat that my heating put into my bungalow โ€“ through the windows, ceiling, floor, walls, etc. I said that I thought he was wrong and that the figure was probably around 100%. He looked down at his script and asserted that the figure was 80%. Eventually he left, disappointed and confused.

I am keen to find out why sulphur hexafluoride is better than air or argon in keeping out noise. I learn all sorts of interesting things on this site. ๐Ÿ™‚

I don’t know how common the use of sulphur hexafluoride may be in glazing. I am only aware of having read about its use – but if it is a greenhouse gas I can’t see it being very popular. I’ve enquired out of interest to our technical department about the CO2 and sulphur hexafluoride question – will let you know if I hear anything useful.

OK – so I was close on my guess as to your profession. ๐Ÿ™‚ And a good scientist is bound to question statements before accepting them as fact (even if you accept them as fact grudgingly…!) and quite right too. It would help me if more customers took your attitude and made me prove the points that make our windows, doors, etc superior to any others. I rely upon them having listened, understood and accepting that those features are important to them. So that when they compare us with other companies and their products they know what they will be giving up if they buy purely on a price driven decision. But the reality is that many people don’t try to understand and therefore don’t question to check their understanding. They are just waiting to know the price. And only a cynic and a fool knows the price of everything and the value of nothing. ๐Ÿ™‚

And you miss my point with Mercedes – it doesn’t matter whether they are or aren’t more reliable than other cars, the point is that they have that reputation (and a few million taxis around the world can attest to that) but it is unwise to just accept that reputation and not question it at the time at which you are thinking of buying one. Any firm can live on past glories for a while, at least. Look at Everest, for example, whilst we are in this thread. But this is why caveat emptor never goes away. Make sure when you are about to buy the particular brand that it is a decision based upon the latest data – which as you agree can include reading Which?

And as a lover of Cadbury Dairy Milk – this buyer is very aware of the speculation that the new owners are changing the recipe, little by little, to appeal to their domestic American market (one assumes) more. And I ain’t going to take that lying down! ๐Ÿ™‚


It is easy to be the questioning sort of person but when I was interested in double glazed windows, I had not much of a clue about what to look for. I soon learned a couple of things to avoid, such as externally beaded windows and doors that could be prised open with a spade. So a bit of explanation and some specifications are useful but I certainly did not want to subsidise the advertising campaigns of Everest et al.

I was very lucky in having a friend who had recently retired as a window fitter. He measured up, gave me a shopping list, explained the merits of several suppliers and fitted the windows and doors, with me offering a bit of assistance. I have never been as lucky before or since. My inexpensive panels have not failed. Had I been employing a company I would have probably purchased fairly expensive panels, but now that I know they are so easy to fit, I would be prepared to take a chance on cheaper ones. I had a door panel broken, probably by the paper boy’s bike and the insurance company’s fitter was making such a mess of my door that I sent him packing and finished the job myself. When that panel failed after a couple of years I just had one made and fitted it myself. It was very helpful to learn how to do the job properly when my friend fitted my windows.

I totally agree that reputation is not necessarily a useful guide for present performance.

You were perhaps fortunate. I learned the hard way what makes a poor window and a poor supplier – I was travelling globally for many years for business in a previous like and even when in the UK was up to my ears, so that my wife made the decision mainly, on the company and the windows. It turned out to be a poor one – and we fell into the trap of not researching enough. Like you, the only thing I thought was important was for them to be internally beaded! Now I know what features are worth paying attention to and which are not so critical.

Don’t make the error of thinking you are subsidising the advertising campaigns of the bigger companies – they have huge economies of scale that make them able to afford to promote their products in more high profile ways, such as TV, radio and national press. As a proportion of spend, marketing costs most companies the same kind of level of turnover, whether they are a ยฃ100m + turnover company or the local man and a van. When you make 10,000, 20,000 windows a week or more, your unit manufacturing costs are lower (though R&D and capital investment costs may be higher because the quality of the product is higher – the volume enables the company to lower component costs through their purchasing power). So you have more absolute ยฃยฃยฃs to spend on marketing – but you are also trying to reach a bigger, national audience. Local Windows Limited may only be installing 20-50 windows a week. Their unit costs are higher, but the cost of an advert in the local paper and Yellow Pages is a lot less. But as a percentage of turnover it’s probably comparable to the national company. But either way, you are paying an approximately equal amount to either company to go into their coffers for future marketing. ๐Ÿ™‚

Anyway – I am off to Eastern Europe for a week, so will thank you for the engaging discussion, for now! I WILL respond again if I get that information on the gas infills, as promised.

I take your point about economy of scale in use of advertising for double glazing and many other products, but big companies are still spending a lot of money on advertising. This sort of advertising is more likely to contain what I regard as misrepresentation (albeit insufficient to trigger multiple complaints to the Advertising Standards Authority) than a small company advertising in Yellow Pages.

I will have a look and see if there are any scientific literature on use of different gases in double glazing. I had not appreciated that the choice can affect sound transmission, and I would like to find out why. Have a good trip. ๐Ÿ™‚

Thanks –

Before I go: http://home.earthlink.net/~jimlux/hv/sf6.htm gives a list of properties for SF6.

SF6 appears to be about six times heavier than air – there are references I’ve found suggesting that it is often mixed with argon for glazing insulation.

Interestingly I also found this site http://www.chm.bris.ac.uk/motm/SF6/SF6h.htm which says: Since the 1970s, SF6 has been used in double-glazed windows to improve sound insulation, due to the reduced velocity of sound. It is, however, no good for thermal insulation.

So I presume that mixing with argon helps improve both issues – though one assumes the dilution of the argon reduces the thermal performance – but I’ll let a scientist confirm that! ๐Ÿ™‚

This is useful: http://en.wikipedia.org/wiki/Sulfur_hexafluoride says: Of the 8,000 tons of SF6 produced per year, most (6,000 tons) is used as a gaseous dielectric medium in the electrical industry, an inert gas for the casting of magnesium, and as an inert filling for insulated glazing windows.

But that doesn’t suggest it isn’t good for thermal insulation.

What claims (out of interest) in the advertising do you think are ‘misrepresentation’ out of interest? A genuine interest.

Now I must fly – literally! ๐Ÿ™‚

Thanks. I will do some investigation and we can discuss sulphur hexafluoride when you get back. We might need to find a more relevant Conversation to discuss misrepresentation in advertising.

Laurie-Anne says:
4 October 2013

Thank you so much to Londoner and Colin Samson for taking your time and trouble to explain the procedure to me…I really appreciate it. I’m happy to say that my windows are now completed and the new ones are perfect and they have been fully paid now. (The scratches were on the inside of the double glazed unit the bit you don’t have access to… so I think their quality control needs tightening up so as not to eat into their profits.) ๐Ÿ™‚

Jolly good – and yes, it does raise questions about the quality checks if the scratches were between the panes. Very careless. But I suppose any company can make a ‘Friday car’, even today. Humans are fallible.

But of course, to err is human; to forgive, divine.

Hope the windows give you decades of satisfaction. ๐Ÿ™‚

Jacklynn Reid says:
24 October 2013

Please do not use the company SAFE CHOICE WINDOWS DOORS AND
Im having to take court action regarding the state of
my windows and door.
They are not answering my calls or letter…Trading
Standards are now involved.

Had Anglian Windows and Doors fitted in July 2014. Complete disaster. Damaged windows and doors, botched installation and very poor customer service. And that’s before I even paid them. All the Managers do is chase you for payment, they don’t care about the customer or the shoddy work done.

Mr A J Beasley says:
14 October 2014

Made the mistake of having replacement upvc windows and doors supplied by Evesham Home Improvements Limited, Unit 7, Willersey Business Park, Willersey, Broadway, EVESHAM, Worcestershire, WR12 7RR.

Windows and doors were obviously damaged and/or faulty.

Evesham Home Improvements Limited refused to acknowledge damage and/or faults.

According to Evesham Home Improvements Limited nothing was wrong with the windows and doors; I was imagining everything; I had damaged the windows and doors myself.

Had to get DGCOS involved to force Evesham Home Improvements Limited to attempt to rectify damaged and/or faulty windows and doors.

Bubbling / blistering of foil covering front door frame, which Evesham Home Improvements Limited said was not visible from 1 metre away, was visible to a building surveyor from 4 metres away!

Unfortunately, DGCOS, being paid for by its fee paying members, ie the companies that it supposedly regulates, clearly works to the advantage of its fee paying members.

Supposed legal advice that I was given by DGCOS turned out to be completely wrong.

DGCOS is as incompetent as the companies that it supposedly regulates.

Evesham Home Improvements Limited refused to reply to letters from me and also refused to accept delivery of letters which I sent to it by Recorded Delivery.

In Court, Evesham Home Improvements Limited admitted that the standard of its work was only “good enough” – thereby admitting that it works to the lowest standards that it can get away with!

Still left with damaged and faulty windows.

Tarquin says:
15 October 2014

Nice article, but aren’t you kind of trying to paint all Double Glazing companies with the same brush.

I mean double glazing is double glazing right? And a car is a car right? Wrong, double glazing various by manufacturer just as in the world of cars there are Ferraris and there are Ford Fiestas!

Also you fail to take into consideration the number of local phoenix companies whom pop up for 3 years, go bust from undercutting the competition (thus being cheaper) – leaving all guarantees meaningless – and then resurface a few months later selling the same product under a slightly different name!

If it were me, I’d stick with one of the big 2 as they’ve been in business over 40 years and are still going. Surely if they were that bad, no one would use them and they’d have gone out of business a long long time ago – taking this back to the car world like Rover………

Frank says:
15 October 2014

Having a major problem with Anglian Windows. The fitters were useless. They damaged my house and the windows and doors they were trying to install. I complained and the send a couple of managers over the next few days. The installation managers were even worse. They could see that the fitters did not know what they were doing, but insisted the fitters were well trained. I have been informed that the fitters are no longer being used by Anglian, as they caused problems everywhere.

Trying to deal with Anglian Customer Service, but they always refer me back to the same incompetent installation managers. I am being harrassed for full payment, even though I had to pay my builder to remedy a lot of the damage caused by Anglian Windows. They also damaged the carpet in one of the rooms which now needs replacing.

Today I had a call from ” James” from Anglian Windows demanding payment. I explained that I had written to customer service and was awaiting a reply. After talking for 10 minutes I asked him his full name. He suddenly hesitated and came up with the usual ” Hello, hello? I can’t hear you” rubbish.

Just what I have come to expect from Anglian Windows. I will be sending photos and videos to various consumer programmes and I hope they warn other people about Anglian Windows.

Frank – sorry to hear of your experience – but why do you say: “Just what I have come to expect from Anglian Windows.” If that’s what you expected why on earth did you order from them in the first place?

I suspect that you have allowed the red mist to settle too low over your eyes! Especially when you then go on to say:

“I will be sending photos and videos to various consumer programmes and I hope they warn other people about Anglian Windows.”

No doubt you have great cause for concern – and you have every right to expect things to be put right, but huffing and puffing about making a fuss in the media isn’t the way to get your problems resolved. The larger firms will occasionally have one job that is not done to a decent standard – it’s life. there is always the ‘Friday car’… If you aren’t getting anywhere with the local depot then I’d suggest that you contact their Head Office – ask for the CEO’s office. You won’t get through to him, but that’s not unusual for any large company – try getting through to the CEO of Tesco, British Airways, British Telecom, etc. The switchboard will put you through to a senior person who will be able to get wheels moving. to resolve your issue. I don’t work for Anglian – but I do have a lot of experience in running major companies and have good insight into the window industry – and I can assure you that no CEO likes to have complaints from customers. In the construction industry it’s not always possible to ensure that you can get a ‘John Lewis experience’ from everyone in the organisation – good window fitters are in short supply at the best of times and I am sure that sometimes crews are taken on who, after training, try to get away with slipshod work. As you have discovered – in your case that crew have been dispensed with. So it would seem that Anglian know they had problems with them. Frankly, I’d imagine you’d have little difficulty getting satisfactory resolution if all is as you’ve represented it, if you just went to the top in Anglian. Every major company, every day, has some percentage of customers who have cause for complaint – sometimes justified, sometimes not. Getting all hot under the collar and writing to the media is a colossal waste of time – unless your particular case is the one in the thousands that these programmes receive every year. You’ve got better odds of satisfaction by contacting the firm directly – going above the local branch management. You have the whip hand – you owe them money and until customers pay in full and sign their Satisfaction Note, the fitting teams and the local managers don’t get paid on your job.

Lynchy says:
24 November 2014

Londoner gives you half decent advice here.

Yes – Try their customer service route – this is often designed to make it as hard as possible to get compensation/correction of their failed service. But you have to “go through the motions” and give them a chance to put it right.

Yes – Go the Corporate Head Office/CEO route. This can be quicker than the above. However if a company is smaller or unscrupulous this does not always have a satisfactory outcome.

Yes – If you are confident you are right, can afford the time or cost. Go the legal route.

Yes – Failing all this – fight back using all means necessary! Social Media/sponsored tweets/newspapers. Use all powers you have in your consumer toolbox to hurt these companies reputations. Do stay calm and do not lie. Just spread the information on consumer websites like this or get your story out there. Watchdog or rogue traders etc.. Unfortunately a lot of consumers are too lazy or not prepared to fight back and those of us who are need to often shout louder. Otherwise we create a festering sub economny of shoddy practices and workmanship.

PS I am currently embarking on my own fight back against Anglian after my whole house was fitted with double glazing and the job was just awful. I’m just starting off though so cannot tell you my personal account of their customer service, but salesman was “ok”, survey was good, installation was terrible so far – possibly a sub contractor. (one of my windows was even wonky and sticking out!)

Only ‘half decent’? ๐Ÿ™‚

Flaming away on the internet doesn’t really achieve much against the real cowboys or the local firms for whom the chance of a prospect customer finding the comment on line is small, because they have fewer customers. And frankly, it can make the complainer look stupid/pathetic too. if it is just a rant. As a last resort with the ‘big boys’ in any industry it can help – I ran out of patience with the largest laptop manufacturer in the world (I won’t mention the name here) a few months back having bought one of their most expensive business laptops. I’ve had the same brand for at least 20 years personally and bought hundreds for my businesses in the past and generally been very happy – I need a reliable machine with good backup in the event of failure. On this occasion I got a real problem machine which eventually developed a fault that I couldn’t cure myself and needed the ‘next business day repair’ I had paid for when buying the laptop. Over FOUR weeks later the machine still wasn’t repaired – spare parts weren’t available, no offer of a loan machine to tide me over, hour upon hour (probably easier to say day upon day)wasted having to get an old laptop out of the loft and reconfigure it, load Windows 8.1 install a backup of the failed machine etc just to stay in business and complete indifference from the so-called ‘support centre’. In the end I had no alternative but to start posting on their Facebook page advising everyone not to be conned by the ‘next business day repair’ agreement; pointing out simply the facts about my experience, etc. After three days and about 20 such posts, a solution was finally found (sent me a new machine). I resisted getting emotional in my posts – just simple explanation of my experience (as I said, I’ve bought hundreds of laptops and desktop PCs for my staff over the years and this was really the worst experience I’ve ever had). But I waited until I’d exhausted all avenues that I could access before taking to the internet – the company is very careful to prevent you finding out the name and email address of its CEO or European Head, so I had to just write to the UK, European and in the end US Heads of Customer ‘Service’ – none of whom did anything at all other than the American who said she’d get someone in Europe to ‘do something’.

Lynchy says:
26 November 2014

Sorry it is decent (but only half the story) ๐Ÿ™‚

Glad you got your problems solved. Great example of keeping cool and using social media to get a result.

Mr Martin says:
15 October 2014

In my opinion it doesn’t matter who you order your glazing from. The lead in time is indefensibly long and the promised delivery date very seldom met.
Nearly all glass manufacturers are either incredibly incompetent planners of their business or just plain lazy.
They obviously do not manufacture in sequence of when the order was placed. People ordering after you can, and do, get their glass before you and maybe that can only be because the manufacturers want to make long runs of “standard” sizes. If you want non standard sizes then to hell with you, you will wait, and wait. It’s wrong.

Sorry, Mr Martin – that’s an incredibly sweeping generalisation. And suggests that you don’t actually know too much about the glass, glazing and replacement window/door industry…

What do you mean by ‘indefensibly long’? If you buy from a small company that is sub-contracting out their supply of glazing panels (made to measure – which ALL replacement windows are – it’s impossible to carry ‘stock units’ – if you ever EVER get a window company telling you that they can supply. and you need, ‘standard sizes’, then you would be very wise to find another supplier), and who perhaps has cash flow issues and can’t get those suppliers to take their order and commit to a delivery; is taking time to get the windows ready because they don’t have the manpower capacity to fit them at the original estimated time; or is shopping around trying to find the cheapest source of glazing units, frames, etc , then you may well find that lead times stretch. The larger manufacturers (the real manufacturers rather than the local fabricators) will have huge volumes of orders, the required stocks of huge sheets of glass to cut to size and make the sealed units in their own factories and the capacity to make the frames. They have very efficient ERP (Enterprise Resource Planning) systems to aid planning and routinely have lead times from order to installation of 4-6 weeks. Don’t tar them all with the same brush.

And you criticise the ‘glass manufacturers’ – the glass makers do not make windows themselves. They supply the glass to the companies that make windows and doors. Their capacity isn’t elastic, but the larger quality glass manufacturers work very much hand in hand with the manufactures of windows to forecast and anticipate demand so that lack of glass isn’t a problem – remember that a glass manufacturer who can’t supply glass is losing money and risking the loss of its customers – the window manufacturers. I’ve never known of an instance where glass supply has been an issue – the replacement window industry isn’t too badly affected by seasonal shifts in demand; it’s actually quite an easy one to forecast demand for, for the major replacement window companies.

The industry splits into two broad categories – the largest in numbers of firms are the local firms who at best may be termed ‘fabricators’ – companies who buy uPVC extrusions and cut them to size, glazed panels etc and put them together in a workshop. Some of them don’t even fabricate – they just subcontract the manufacture out to a third party. All of these firms are subject to the supply chains of their suppliers to be able to fulfil their commitments to their customers. The other category is the true manufacturers – those who blend and extrude their own uPVC, cut the glass to size, make their own sealed units and put them all together. There are very few real manufacturers. I know of only one that really fulfils that criteria, though some of the other ‘big brands’ claim that they do. Seeing replacement windows being made in such factories is a truly fascinating experience – you might find it interesting to do so sometime!

Susan Burrows says:
4 November 2014

We had double glazing fitted by a local company we used in our previous house, big mistake. Fitters were not up to the job, Brand windows subbed out to contractors. We had the fitters back 4 times to refit windows, we still have a major problem with one window and another that is stuck with tape. We had 4 windows fitted by Anglian and what a difference, the quality is excellent no. Is fitting, no condensation, no drafts vents, thank you Anglian, only wish we had used you before. FENSA have no service to help dissatisfied customers get properly fitted windows!

WatchdogUK101 says:
25 November 2014

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