SmartSash sees sustainable housing onto awards shortlist
19th June 2012

The SmartSash window from Halo has helped put a ground-breaking project in Warwickshire onto the shortlist for one of the construction industry’s top awards.

The Beausale estate was refurbished under the 'Rural Innovation for the Future' (RIFF) programme, which is now one of six projects being considered for the Construction News Awards 2012.

“Being shortlisted is a fantastic achievement. Our expert judges select only those companies that have demonstrated the highest standards in the industry,” said Editor Rebecca Evans.

RIFF is the first programme of its kind in the UK, and will see social housing units across the country retrofitted with ground-breaking technologies that cut carbon emissions and energy use. Low carbon consultants Encraft, together with Warwick District Council, won the competition to run this pilot scheme against 400 other bids with affordability being a prime consideration in choosing building components, according to Encraft project manager Helen Brown.

“The SmartSash window not only provides excellent U-values but is also good value when compared to similar products. This was an important issue as the scheme has to show solutions that are cost-effective and that can be rolled out throughout the country,” she said.

The properties are three-bedroom semi-detached houses built in the 1930s and were chosen as typical of rural properties found across Warwickshire and the rest of the UK, being poorly insulated and entirely reliant on electricity for heating, being off the gas network. This leads to massive fuel bills: one tenant, using an electric boiler for heating, was £6000 in arrears with their electricity supplier.

The project was set ambitious targets: cut primary energy requirements by 78%; cut carbon dioxide emissions by 95%; and improve the whole house U-value to 0.9w/m2k. The retrofit measures also had to take place while tenants remained in the dwelling to prove there would be minimal disruption and so none of the costs associated with temporary re-housing.

This requirement ruled out invasive insulation measures such as floor insulation, so Encraft had to achieve PassivHaus or near PassivHaus standards to compensate. The triple-glazed version of SmartSash, with a U-value of just 0.7w/m2k was ideal, particularly when paired with Bowater Doors’s Eco Series Composite Doors, achieving the target u-value of 1.2 W/m2K.

Encraft opted for the highest performing version of SmartSash, but the ‘modularity’ of the system enables PVC-U doors and windows to be fitted now to comply with the Code for Sustainable Homes (CSH) Levels 3, 4 or 5 as required – and then be simply, easily and inexpensively upgraded to Level 6 standard at a later date. It also allows for much larger sash sizes, while maintaining thermal performance. This is achieved through glazing elements, which can be changed and enhanced as budgets provide.

Government policy, articulated in the CSH, says that by 2016 – 2013 for the social sector – all new homes will have to be zero carbon rated (Code level 6), meaning that all windows must have a U-value of 0.7 W/m2K or less, while all doors achieve a U-value of 0.8 W/m2K or less.

Essentially, specifiers and building owners have four opportunities to fit now and upgrade doors and windows over time and as resources allow. In the first instance, the door or window can be installed in an ‘entry level’ configuration – featuring a standard 28mm double glazed unit, with thermal insert, which offers a U-value of 1.2 W/m2K.

Second, a unique parting bead arrangement allows for performance enhancement with the subsequent insertion of a third, single pane to effectively create a triple-glazed installation. If the third pane is 4mm float glass, then a U-value of 1.0 W/m2K will be achieved and CSH Levels 3 and 4 will be met. However, and thirdly, by then substituting a 4mm hard coat glass with an emissivity of ε0.10 for the float pane, it will achieve a U-value of 0.8 W/m2K and meet CSH Level 5.

Ultimately, the entire glazing arrangement – as in Warwick – can be fitted with 44mm argon triple-glazed units to achieve a U-value of 0.7 W/m2K. There is also a glazing arrangement that gives a sound reduction up to 50 dB, whilst still achieving a U-value of 1.2 W/m2K. This level of performance does depend on the initial installation of an outerframe incorporating foam-filled inserts at the outset.

The Eco Series of double rebated doors in the public sector from sister company Bowater Doors is capable of achieving a u-value as low as 0.8W/m2K, equivalent to the Code for Sustainable Homes Level 6.

www.halo-uk.com