cav9 Drip, drip, drool...

Rieniets Architecture I Love the look, but you mention better materials to improve thermal performance, but isn't steel still steel ? and therefore will never meet thermal performance requirements.

midmodfan I always loved the look of steel framed windows, most of all when they are black.
Don't know about the thermal performance when the frames are very thin overall - there's very little 'room' for the insulation, no?

But then again there is a Swiss company called Sky-Frame, see sky-frame.ch/e/. They build windows with almost invisible metal frames, yet the U-values are incredibly good. So it IS possible, albeit prohibitively expensive. 70 feet of floor-to-ceiling windows would have cost us 80,000 Euros, that is over $100k ...

Bud Dietrich, AIA @Rieniets Architecture - My understanding is that the system has a much improved thermal performance because of better insulated glazing panels and better assembly techniques, like the addition of thermal breaks. In fact, some buildings using these types of windows have received USGBC LEED certification.

@midmodfan - Unfortunately, these systems aren't inexpensive. Last time we priced out using Hopes Windows it was considerably more than standard windows but way less that what you mention.

Rachel Tanner We live in a bush fire zone in Australia and must now build with steel. As a result we now have options where frames a made with steel casing on the outside and wood on the inside. This allows for bush fire protection but added warmth inside.

Yesmean I love these and would love to replace the aluminum window in our new purchased ranch. I have also found them to be more expensive and would like to find a reasonable vendor in So Cal.

Crittall Windows Limited I would like to make some assurances to Rieniets Architecture, and anybody else, regarding their comment on thermal requirements. We have been producing mild steel non-thermally broken steel windows since 1849, and the performance levels in terms of thermal insulation have always been of concern - as specifiers understandably worry about cold bridging.

What one has to take into consideration with steel is that it only transfers around 1/3rd of the heat energy as say aluminum and so the aluminium window manufacturers have a much harder time complying. Also, with super slim section profiles and generally only a single web of narrow (normally around 1/8” thick) steel running from front to back on each profile – the actual amount of heat loss is also greatly reduced. Compounded with the low heat transference, this leaves a product with thermal insulation properties are generally very good – without the need for thermal breaks. We try and steer away from thermal break in steel window because as soon as they are introduced, there is of course a loss of profile strength, and it is this inherent strength which is the key point to being able to produce slim profile window walling.

It must also be worth noting that due to the small section profiles, more sun energy is absorbed by the building as a result in comparison the larger-profiled systems such as aluminum and vinyl. Coupled with IGU’s generally either 5/8”, ¾” or 1 1/8” thick – this gives the scope to use high energy efficient glass units, and with integrated weather stripping on the opening windows – heat loss through gaps in openers is a thing of the past.

And lastly, whilst we are on energy conservation, please also bear in mind that (our) steel windows are rolled from 100% content recycled billet steel, which can also be recycled at the end of its long life (a life that is especially lengthened by our hot dipped galvanizing and polyester powder coating).

So, not only do they look fantastic as can be clearly seen in Bud’s photos, they are a very good product in terms of efficiency. It is not always down to just the U factors.

Thunder Hill Design Black steel frame windows span architectural styles; they are present in greenhouses and older stone mansions and cottages. The thin, dark structural members frame the view out to lawn and garden, enhancing yet unobtrusive; and look striking either left bare or dressed with long romantic sheers or heavy rich brocade.

Bud Dietrich, AIA @Crittall Windows Limited - Thanks for all of that really helpful info on the energy efficiency of steel framed windows. I especially like the recyclable issues as it helps reduce the need for landfill area.

Crittall Windows Limited No problems Bud, if you require any further information, technical information etc, please don't hesitate to ask. There are so many misconceptions about using steel windows and doors, we really do try and give un-commercial, un-biased help wherever we can to help strengthen the steel window industry for both or our UK and US markets. Regards, Darren Joyce - Crittall Windows Limited.

mgranskou I don't doubt that steel has come a long way on the energy efficiency track, however, wish to point out that one can achieve close to the same architectural effect with fiberglass windows and they are the most energy efficient on the market. These are black fiberglass that look a lot like steel. With respect...

Crittall Windows Limited Hi mgranskou. Absolutely correct in that fibreglass is a wonderful material for windows in that it is energy efficient, strong and holds a fair amount of structural integrity compared to other currently-available materials on the market.

There are a few known problems though with fibreglass. The biggest is cost. It is widely known that fibreglass windows are very expensive in comparison with other materials.

Also, it is when you get to fine details that the differences are evident and the real selling point of steel strand to the forefront. One of the beauties of mild steel is that all frame corners are welded, galvanized and powder coated to form a complete unbroken surface around the frame. Fibreglass windows are still mechanically jointed and therefore not only do you see that break point - you also lose a fair amount of structural integrity with larger openers not being possible as a result. The surface of fibre glass is of course relatively "hard" which is good for surface finishing, but with (and I may get corrected here!) air drying paints. On the opposite side of the scale, mild steel will always hold its electrostatic applied thermosetting polyester powder coating much better than applied finish to fibre glass, which of course lengthens the maintenance cycles and thus reduces on-going costs when using steel. Added to the very high cost of the windows to begin with makes the choice of fibreglass for specifiers difficult to sustain and justify when the firm costs come in.

Another key point is the holding of fasteners (hardware, handles, hinges and the like) to the frame members. Steel obviously once drilled and tapped offers a secure sound thread to hold such items. Fibreglass, although better than vinyl, will never hold a fixing as well. Therefore it can be safely argued that the service life maintenance level involving re-fixing of hardware, corner cleats fixings, hinges will be higher in fibreglass than in steel.

There is absolutely nothing wrong with using fibreglass as a window material and actually fits our ethos of strength, finesse and longevity (to a point) - but we would pose the questions: why pay more money for something that almost looks as good, almost lasts as long, almost has as small a profile section and almost performs as well - when the real deal can be had for less, will last longer and will perform better?....

Barnes Construction LLC I am in Florida and need hurricane/wind impact windows. What is the opinion on this please.

Monte We are going to be building a modern home and using metal aluminum windows. Ours are a bit "thicker" since we like the bolder crisp break lines and how they look.

They are essentially commercial windows that you see in most store fronts throughout the USA.

There are two types standard and we're going with thermally broken frames. I didn't get how until I met with a glaizer and he showed a section where the have a composite material that ties the metal on the outside to the metal on the inside of house which doesn't allow the cold or heat to transfer through since there's metal-composite materials-metal. It's certainly not perfect I'm sure but I've heard it's a significant efficiency gain.

We're also paying to have insulation blown into the box section/open part of the hidden frame which will make a significant difference. The window supplier recommends this for residential applications since the HVAC needs are different than commercial.

In total, the thermally broken, metal, insulation option is extremely expensive but the look is stunning. Another reason we didn't break ground yet and socking away every nickel we can...but it will be worth it....until my wife finds out no Chanel purse for Xmas this year.

Crittall Windows Limited @ Barnes Construction LLC – To put your fears at rest, a range of opening and fixed windows from one our mild steel window ranges - the Crittall Corporate 2000 range (glazed with a set make up laminated IGU) has been fully tested, evaluated and accredited by ATI in accordance with:

ASTM E1996 - 12 Standard Specification for Performance of Exterior Windows, Curtain Walls, Doors, and Impact Protective Systems Impacted by Windborne Debris in Hurricanes

E 1886-02, Test Method for Performance of Exterior Windows, Curtain Walls, Doors, and Storm Shutters Impacted by Missiles and Exposed to Cyclic Pressure Differentials

For Missile Level D / Wind Zone 3.

As a side note, this is another key selling point of using mild steel windows and doors. The inherent strength of the profiles mean that we do not have to increase profile sizes exponentially to deal with increased required resistance to wind, water and air penetration - in addition to enhanced impact resistance.

Blue Sound Construction, Inc. @Crittall-I also appreciate the detailed information you are presenting. On cost though, are you saying that your steel windows in general cost less than fiberglass?? Say Milgard Ultras for example?

Crittall Windows Limited @ Blue Sound Construction, Inc. - No problems - here to help - We have found that steel windows can be considerably cheaper than firbreglass (NOT than vinyl though). It depends heavily in the elevation of the required walling or windows. Remember, as steel is a fully welded construction - all of the money is in the factory labor for the welding and construction, all of the actual material constant is fairly unimportant. In other words - we could could do a super sized version of a smaller windows, say three times the size. But the cost might only be 30% higher than the small window. This would not be the case in fibreglass or some other material such as aluminum where the base material represents so much a bigger part of the installed cost. Therefore, where you have bigger windows, where you want lots of glass, where you want to make the most of natural daylight - basically where mild steel windows excel, then this is actually where the biggest savings can be made.

(On a side note: One must put aside some prices of historic local US mild steel window manufacturers and associated prices. We have been exporting steel windows from the UK for many years and over 160 years of manufacture have shown us how to make these not only to exceptionally high quality - but also to economical prices in comparison to more known US manufacturers. Lead in times are also lower, even with 2 weeks sea freight)

Our established US distributor network sell other material products such as wood, aluminium, bronze and clad windows and so constantly feed us comparative prices for our product vs. other materials. This enables us to gauge price point against other products.

We are not saying it is a cheap product, but it can be very cost effective for the correct building. And what it can add to the finished build is, of course, priceless!

lamicq What about double glazed window panes? These are great but how can we work this in Colorado? If the frame is thicker to support double glazed than can we do a thermal break and keep the structural integrity?

Blue Sound Construction, Inc. @Critall--thanks again, that makes sense.

Crittall Windows Limited @ lamicq / @ Studio One - All of our Crittall mild steel windows and doors take double glazing IGU's varying (depending on the range) from 9/16" up to 1 1/8". With this level of insulation in the frames, and with a choice of TDL and thermal-insulation-friendly welded (to one side) SDL muntin bar configurations, we do not need to introduce compromising thermal breaks into our systems to meet the majority of local requirements. The current pricing levels of thermally broken steel systems are usually around 2-3 times the price of non-thermally broken. For this you may get a minor increase in overall combined frame/glass U factor/value by using the same center of glass U factor/value IGU. We are aware of the stringent requirements of Colorado, and through our distributor in Eagle County we have been looking at compliance by way of NFRC ratings. This is being developed as we speak. There are always options though and the best thing is to approach the Technical Services team of your prospective supplier (always us we hope of course!) and get them to roll out a bespoke U factor simulation for the particular project in mind.

melissaslattery Love, love love the look of steel framed windows. The problem is that I our house that we are soon to build is literally a stone through away from the salty waters of Australia. How does the steel window frames hold up in these conditions? Is there a treatment that can be put on these frames? Anyone know who produces the steel frame windows in Australia?

wolfgang80 I love the look of steel windows but when it came to replacing our existing windows and adding new openings, the price was prohibitive. A single operable 4x4 Hopes Window without glazing or installation was $3,000.

Sean Rinde Does anyone know of a California window company that makes windows like this? We have a project that we're working on that would be perfect for steel windows.

barsee We live on a SF hillside with east to west exposure. Our steel windows, architecturally speaking , are beautiful in that New Urbanism style but the moisture, mildew, heat escaping problem has become measurable. Any specialists out there that we can consult?

Crittall Windows Limited @ melissaslattery - just to let you know that as well as hot dip galvanizing to protect our mild steel windows at base level, they also come with a factory applied electrostatic polyester powder coat from Akzo Nobel Interpon. We also do, at a slight premium, a special dual coat higher quality powder specifically for harsh marine environments as well as high UV differential exposures. We also have a distributor just outside of Melbourne.

Crittall Windows Limited @ wolfgang80 - please do not take that as general price for all steel window manufacturers!

Crittall Windows Limited @ Sean Rinde - we have 4 distributors in S. CA and 1 in San Francisco who specialize in our Crittall Steel Windows and Doors.

shanmcstan I love the look of steel windows but we also live on the ocean in SF and have found that only bronze will withstand the elements here. The estimate to replace our high maintenance wood windows with bronze was more than the price of an average house in our city!

melissaslattery WOW! this is wonderful site. Thanks to all that have helped me enormously.

Rieniets Architecture Crittal Windows, can you name your distributor outside Melbourne.
Thanks for all the great info, and I can certainly appreciate all the benefits of steel as a sustainable material and its thermal properties that you have mentioned, but ultimately it is the U-value that we have to comply with here in Oz, so it would be great to get some info from your distributor, cheers

Crittall Windows Limited @ shanmcstan - you are correct in that bronze is very expensive, much more than steel. It is though a great product and would outlast many of the houses that they are fitted to! Mild steel though is just as long a lasting product if treated correct and hot dipped galvanized (as opposed to electro plating or spray zinc coating which are not as hard wearing - see US galvanizing association for detailed research). And when also coupled with factory applied powder coatings to marine standards where required (see previous comments) - makes for a long lasting product in steel. I was at Pier One which we did the windows on in SF a few weeks back. We did the windows a good 10-12 years ago in galvanized powder coated Corporate 2000 range (see all the entrance screen). You couldn't get much closer to the sea, and those windows have stood the test of time exceptionally well. And marine standard powder coat was not available back then and we used our standard everyday powder.

Crittall Windows Limited @ Rieniets Architecture - see below, and thanks for the interest.
http://www.crittall-windows.co.uk/news/1/76/windows-on-the-world.html

All About Windows Inc The thermal issues have been resolved. Today there are steel windows and doors that are completely thermally broken, and can accept insulated Glass. See our info on Houzz, under Steel Windows and Doors.
Or feel free to contact me. Roland@allaboutwindowsssc.com

Crittall Windows Limited I should also have added that our Houzz entry is under Crittall Windows Limited, and my email address of darren.joyce@crittall-windows.co.uk is always open to enquiries.

Steel Windows and Doors there are completely thermally broken steel products out on the market today. They can be fabricated in Painted Steel, Bronze, Cor Ten and Stainless Steel. If interested feel free to contact us. roland roland@allaboutwindowssc.com

Crittall Windows Limited For those interested in steel windows - you may like to see our new corporate film here ( ) which shows our factory in operation as well as office capabilities - and in the second half. has a showcase of some projects in the US and UK.

rudyfabre My experience with steel windows has been at a high-end classical firm. We received the steel window frames unglazed, and they were pitted and had holes, etc. They required a lot of prep work before installation and glazing. I believe they were Hope's.
Has there been any further advancement in the quality of steel windows when they're delivered? Are they available glazed? Do they have nailing fins?

Crittall Windows Limited @ rudyfabre - so sorry to hear your experience of steel windows was not a good one. I cannot obviously comment on a competitors product, although it is expected with any manufacturers steel windows there is going to be a degree of evident roll marks in the surface of steel substrates due to the rolling procedures to form these intricate mild steel profiles. We call it the "organic" look of a natural product! That said, due to our hot dipped galvanizing procedures the zinc tends to smooth our most imperfections in the surface quality, and as long as the pre-treatment prior to coatings are done correctly - pitting should not exist. The thickness and bonding of some lesser quality treatments means that natural "smoothing" is not as efficient as a simple thin coating is applied as opposed to a thick lustrous coating of zinc that actually "eats" into the surface of the steel itself - merging with the surface as opposed to simply being stuck to it. See the video above showing the pre-treatments and galvanizing for a better idea.

Pitting is usually the result of insufficient de-gassing of the surface of the product prior to coating with the finish. If not de-gassed, the air will expand under heat (usually during thermo setting) and this can "pop" open through the surface finish - leaving a pit or hole. Not very attractive. We have spent many years as an approved applicator for Akzo Nobel Interpon Polyester Powder Coatings, and you would not believe the number of pre-treatments that are required prior to coating! Expensive, time consuming but absolutely necessary to attain the correct finish. If it doesn't come out of the oven to an acceptable certified standard, the windows windows should not get past Quality Assurance procedures, and should be stripped and re-done.

In regard to nailing fins, these are not appropriate for steel windows due to their weight. Steel windows must either be screwed directly into the structure through the frame, or they can be fixed with "Z" shaped fixing clips. All our steel windows have purposed made fixings to suit the application - either simple countersunk fixing holes to the perimeter, or with "Z" fixing clips/lugs that attach to pre-drilled/tapped fixing holes on the window perimeter (using supplied machine screws). The installer then simply makes the fixing to the structure through the other end of the "Z" clip/lug through a pre-drilled hole. The clips/lugs are all rustproofed after drilling holes and forming them. All lugs/clips are sized to suit the structural surround details, and all are constructed from steel.

In regard to factory glazing then there are very good reasons why steel windows and doors are glazed in the field. The first is the weight. Steel windows and doors weight more than your average window and therefore if they were factory glazed - the handling in the field would be difficult and dangerous - especially with large frame windows for which steel is synonymous. The second reason is that due to the slim line front-to-back dimensions of steel windows - the fixings run through the profile directly under the edge of the glass, meaning that the glass must go in after the fixing has been made.

Hope this helps, and hope you will use steel windows again in the future, albeit through another supplier ;)

Crittall Windows Limited @ rudyfabre - just to carry on a bit from previous post, I have attached here a picture (** PLEASE HANG MOUSE OVER PICTURE TO SEE ALL 4 GRAPHICS! **) showing what I mean by the affect of hot dipped galvanizing vs. other lesser corrosion resisting treatments such as electroplating. You will see on the left, how thick the zinc coating is and how it actually eats into the surface of the steel substrate (the steel is lowest band of color). You will see how the surface is "wavy" as it merges with the zinc as opposed to the electroplating graphic which shows the simple thin applied coating. The result is a long lasting and damage-resistant hard wearing surface that when properly pre-treated takes a polyester powder coat well to provide a flat (except the natural roll marks as previous post), even and pit-free finish.

canoe1 please!!!!!!! Can anyone recommend a current manufacturer of the steel windows ?

morgana44 Love love love steel windows. This ideabook is the best yet for great information on a product that I had no idea about. Terrific information in a format we can all understand. And many thanks to Critall Windows for taking the time to educate us.

Bud Dietrich, AIA @canoe1 - Two such manufacturers are Crittall Windows Limited, who have been really active & provided a lot of good information here, and Hopes Windows.

Steel Windows and Doors Brombal fabricates Steel Windows and Doors that are completely thermally broken, and can accept insulated glass.

They have 3 different frame profiles, that allow them to produce Sightline Window/door Units in both True Divided light and Simulated Divided light configurations. Their largest profile allows for curtain wall applications "Commerical store front" modern type of design.

Frames are fabricated in Painted Steel, Solid Bronze, Stainless Steel, and Cor-ten.

Brombal is also under going Impact rated testing of their units for Miami Dade.

If interested give me a call as we are a regional dealer located in the Eastern USA. thanks
roland roland@allaboutwindowssc.com

Universal Window and Door, LLC @barsee, the moisture issues you mentioned may have more to do with the humidity levels in your home than the windows themselves. In any case, condensation on windows is caused by a variety of factors. Feel free to contact me for suggestions on impoving those issues.

Panorama Windows, Ltd. Pultruded fiberglass windows DO have narrow frame details and can have the same forged bronze hardware as steel windows but without the same condensation problems on the frame and eventual rusting that steel windows have. The installed cost of a quality fiberglass casement window should be less than that of a steel casement because of not only lower window cost but also because they are easier to install.

Faour Glass Technologies Hello- sorry to chime in a little late here, but we are just getting set up on Houzz. Great article Bud.

I am responding for a couple reasons.

1) We are the preferred Hopes Installing Dealer for the west coast of Florida / Tampa Bay Area. If there are any questions you have on a Hopes product please feel free to contact us.

2) We now have the U.S. Patent Pending for the first ever structural (butt glaze) glazed impact-resistant glass system for exterior residential and commercial applications. This provides a completely un-obstructed view with the peace of mind of impact resistance.

Our Slimpact product is completely frame-less, with glass viewing areas 10' tall by any width.

ASTM E 1996 Missile D tested / Zone 3 with 60 PSF design pressures.

If you are in an impact zone, and you do not want to compromise on restricting your view, Our Slimpact system will provide the best un-obstructed view.

If you have any questions please feel free to visit our website (being updated currently) or contact me directly.

Bowden Carroll Design The comments I've read here so far are like an ad for Crittall Windows - and why not? I lived in a block of flats built in the 1930s that had Crittall windows and the scale of the glazing elements was exactly right for the "rhythm" of the brickwork. Then some owners started putting in big, fat, thick double glazed windows that totally destroyed the elegant look of the blocks of flats. Broke my heart. Yes, your heart CAN be broken by a poorly selected window style!

sohme What about the insulating value? Does it conduct heat and cold into the home? Are the Northern plains not an option for this construction?

Crittall Windows Limited @ sohme - thank you for your interest in steel window products firstly. Your concerns over the insulating values of steel windows are valid, but technology has moved so fast in terms of insulating glass units that as long as the window system is capable of accepting a good thickness of IGU, then your fears can be put to rest. Crittalls have systems capable of accepting units upto 1 1/8" thick. This permits the use of good inert insulating gasses in the IGU such as Argon, Krypton and for smaller IGU's - Xenon, although the latter is very expensive. When using these gasses in conjunction with a good low emmisivity coating to face 2 or 3 of the unit, results in excellent low U factor/U values. Although steel windows are seen to not be thermally efficient, due to the small amount of steel profile on face as well as that running front to back and the low thermal conductivity value of steel compared to say, aluminium - the resultant insulation values can be very good. This has enabled us to sell and use our products US wide. It is true that due to the high insulation values offered by wood windows for instance, that there are of course more insulating systems overall on offer. That said, the small face profiles of steel windows enable more solar gain to be achieved in comparison the large profile wood and aluminium systems.

With all design, it is of course finding that compromise between good design, and desirable performance levels. Steel windows offer that compromise, and with good design (large pane windows with simulated divided light muntin lites where required / Only using larger profile operable windows where really required, etc.) class leading thermal insulations values can be achieved.

If you are at all worried please do drop me an email with any inquiry you may have and we would be happy to computer simulate out projected U factors for a specific project.

Hope's Windows, Inc Hi folks- very late to Houzz, but thrilled with such a wonderful site. Kudos to the Crittall folks for the excellent tutorial on the merits of hot-rolled steel products. Many of Hope's products also have NFRC certifications and FBC compliance for those of you in hurricane markets. We would be happy to answer further questions as they arise and greatly appreciate the interest in steel and bronze!

Faour Glass Technologies I wanted to show you some pictures of a finished job in Hope's steel windows and doors that was recently completed by our company in Tampa, FL. The job is located at the Oxford Exchange and the reviews have been flattering: