Actually at home (I work from home) we already do our bit – most of our lighting uses compact fluorescents. The rest are low-voltage halogen luminaires which could be replaced with LED lamps. All of a sudden it seems LED lighting for the home has made a dramatic technological leap in terms of lumen output making them comparable with compact fluorescents (could this possibly be because of the EU ban on incandescents – hmmm?). Apart from having a life time of up to 10 times that of a compact florescent, LEDs do not contain mercury.

I have yet to see LED lighting in action in an interior domestic situation where it is required for brightness and not mood lighting – my only experience of serious LEDs is with my Petzl MYO XP headtouch which I use when I’m out in the mountains and a Cateye light for cycling – the output of both is phenomenal.

There is a great deal the construction industry can do to cut carbon emissions, not just in the embodied energy of materials & the process of construction itself but in designing buildings that minimise energy use over the building’s lifetime. To use a clichéd phrase – it’s not rocket science. Dwellings that rely only on the heat output of human bodies and lighting for heating do exist.

And it’s not just energy usage – we also need to to be addressing other issues such as toxicity of materials & water usage.

The introduction states that the thermal performance of buildings designed to Building Regulation requirements (or better?) is such that they could actually be ”consuming in excess of 40% more energy than the predicted values”, and possibly much more in some cases!

I’d recommend people to read it.

Despite the controversy surrounding the claim by Actis that Super 10 has a U-value equivalent to 210mm of mineral wool, TRADA continues to support the product for roof construction applications.

Government department Communities & Local Government has recently published (18 June 09) a report on multi-foil insulation by Professor Philip Eames of Loughborough University. At the same time they have issued a circular & divisional letter.

The Department continues to support the so-called ‘hot box’ test and other tests agreed at a European level for insulation materials and that results from such tests only will carry a ‘statutory presumption’ of being correct. The Department, however, accepts that there is a scientific dispute over test methods and that Building Control Checking Authorities and Approved Inspectors are therefore free to decide for themselves whether to accept a construction detail that involves a multi-foil (as has always been the case it seems).

For those of you who are interested there is a long running debate on multi-foils at the Green Building Forum.

For several years my Local Authority Building Control department has refused to accept Actis Tri Iso Super 10. I’ve just finished two loft conversion designs and we used MLM who are happy accept Actis.

Re sash windows – the first answer is to (retro-) draughtseal them – otherwise air movement through the window will lose more heat than the single glazing, and would render any more sophisticated glazing irrelevant.

A second answer alters the architectural appearance to some extent, and is to secondary glaze. This glazing can be single or double but will lead to a more cluttered look in the window reveal, especially since it must open both for ventilation and so as not to compromise egress reqs. If the inner glazing system is draughtsealed and the original outer glazing is vented to outside, then condensation issues shouldn’t arise.

A third answer is to re-sash the existing boxes to incorporate double units. You ’steal’ the original depth of the flat between rebate and mould, gaining 12.7mm, and extend the sashes slightly (say 3mm) into the parting bead gap, and if you can achieve a rebate of 25mm thereby that could comprise a 9mm seating for a bead aginst a 14mm unit, the rest being seating/sealing materials, presumably in this case silicone from a gun (low modulus, like most glaziers use), since it’s thinner than applied glazing strips. The unit itself would be 4-8-4K with krypton fill. The problem is the weights, and how you solve that will depend on the proportions of the window. If square section lead to the max length insertable into the pockets won’t do it then you can add make-weights to the cords, but only up to the max length that will allow full travel of the weight stack inside the boxes.

Or junk the weight idea and substitute spring balances recessed into the new sashes rather than the box frame (which isn’t thick enough).

Or make a complete new window, but as in all double glazing options small panes = thick bars and the only alternative that mimics visual proportions is fake bars applied with adhesive to the glass surfaces. Not so good close-up. Partially effective from a distance.

There may come a point at which energy conservation must outweigh heritage in most cases, & I’m tempted to suggest that that point is now, Philistine though it may seem.

Then a 2nd email suggesting…

Even 6mm krypton wld be good – poss U of about 1.5? More energy intensive (embodied) than the less effective argon, though, & what’s the life of a glass unit seal?

Most site glaziers seem to use silicone as a default – for ease of use and adaptability? – but apart from them there seems to be a consensus that dry glazing with a vented (drained) rebate is healthiest for the unit seals.