The Green Building Store ( no relation) have just launched a new range of aluminum clad windows so they will be deep green. I'm not sure if they are exhibiting at Ecobuild though.

Alu clad windows are really only classed (by me at least) 'eco' when combined with a high rise build though. On houses timber only would be a more eco choice.

Who is Ours Ian?

VELFAC are able to offer the following u values:

1.54w/m2 - 4-16-4 unit argon filled + 1Nr low e coat.
1.48w/m2 - 4-16-4 unit argon filled + 2Nr low e coat.
1.18w/m2 - 4-12-4-12-4 unit argon filled + 2Nr low e coat.
0.99w/m2 - 4-16-4-12-4 unit krypton filled + 2Nr low e coat.

VELFAC windows are tested for air permeability up to 600 pascals with a recorded air leakage rate of below 0.12 m3 /(h.m2) at 50 pascals. Approved document L1 allows a reasonable design air permeability rate of 10 m3 /(h.m2) at 50 pascals.

You may wish to read a report that I recently downloaded from the internet, which was compiled by Napier University's (Edinburgh) School of Engineering. This report illustrates the life cycle of window materials and offers a comparative assessment of PVCu, aluminium, timber and aluminium clad timber windows. Incidentally, this report does not encompass the VELFAC window principle, which is a true composite window, i.e. timber internal/main frame and an extruded aluminium external sash.

http://www.cibse.org/pdfs/Masif.pdf

As you will see, the report focuses on the embodied energy, which is the amount of energy consumed during the manufacturing process. The report also assesses the durability of the frames and expected life cycle.

In conclusion the report suggests and endorses that aluminium clad timber windows will provide an expected service life in excess of 40 years.

Timber could not hope to achieve this, even with a regular maintenance regime. However, timber is a carbon neutral product and this is one of the main benefits for using it within an aluminium clad timber window construction.

In the experience of many local authorities, PVCu will not achieve a lengthy life cycle. I personally think that the expected 25 year life cycle of a PVCu window, illustrated within the report is rather optimistic. In addition PVCu tends to get land filled, which allows the release of environmentally dangerous substances, thus contaminating adjacent land.

Aluminium can be repeatedly recycled and with production facilities powered by environmentally friendly sources such as hydro-electricity schemes, the argument for aluminium becomes more credible.

A lot is said with regard to the energy used to produce aluminium, however little is said with regard to the energy used to produce glass as it is assumed all glazed units have a similar lifespan.

It seems acceptable to consider a sealed unit housed in a timber frame as having an expected life if between 10 and 15 years, whereas with a true composite window the glazing is housed in an aluminium sash. All VELFAC sealed units are factory installed, drained and sealed. It is my considered opinion (and VELFAC UK experience) that sealed units installed and drained correctly and housed in aluminium sashes can and do last 20+ years.

There are a couple of companies that make BRONZE and Bronze clad wooden windows if they are of interest... No need for paint or coating like Aluminium.. Perhaps a tad expensive.

http://www.fensterbau-wetzel.de/index_en.php (German quality, modern design, choice of woods, good U-Values)

http://www.bronzecasements.com/ (Solid metal, traditional design, ideal for heritage/replacement)

http://www.bronze-window.com/ (American, not sure if they export).

tomlin,

At no point on the window does the aluminium form an internal surface.

VELFAC windows are thermally proven (see u-values above which are whole window values).

Prices are competitive, thus VELFAC supply more composite windows in UK than any other.

It's not just the up-front price that counts. Try dividing the price by the number of years you expect the product to last.

Don't do it!

Alu clad painted windows are only low maintenance if they are properly wrapped in the factory before shipping. We've had two sets of cladding and a "magic man" and ours still don't look great after only 4 months. To be fair, the manufacturers offered us a third set of cladding, but its not the best green option.

If I could do it again, I'd order timber 3G units and have them stained in a linseed based paint like Holkhams or equivalent.

There are not many downsides to alu-clad really, virtually maintenance free, only thing I can think of is if the surface got chipped the touch-up might show - like it would on the surface of your car. But hey theyre a great protective surface to the timber window underneath.

docmartin, I am reading your comments, and I do have aluminium cladded windows and they were so easy to fit as we got fitting instructions from the supplier we used. They came very well packed from the factory and we never had any problems with the surfaces being chipped as Alec1702 has had

Hello all,

I am trying to find a company who will do alu-clad or alu-wood type windows( PALE GREEN EXTERNAL WITH OAK INTERNAL) for a barn conversion we are currently working on, i am finding it very hard to find any company that trades in the shropshire/worcester area, if anyone has any contacts or can recommend a company that trades in this area can you please let me know?? we are having to supply our local council with a sample of what we want, thats even before we can place an order for them to even approve the type of windows we want, they seem to have been about for some time now but with very little information, please can anyone help with our problem!! thanks for reading,

Fay.