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Observer Ethical awards Winners 2011

YouGen Blog

Secondary glazing for sash windows cuts cost and increases comfort (Revised)

Posted by Cathy Debenham on 21 December 2011 at 2:50 pm

Winner of our Keep Warm: Spend Less competition

'I bought my existing house in 2009 and, although the walls had been well insulated in 1994 by the developer with 100mm expanded polystyrene fitted between the studs, there were improvements that could be made,' writes Brian John Griffiths, one of our shortlisted contributors.

'Firstly, I topped up the 100mm of glass wool loft insulation which had partially slumped with a further 150mm of an equivalent product.

'I ignored the Energy Audit’s recommendation to replace the ancient 1994 gas boiler with the latest condensing version as the machine was still in good working order and had been serviced annually. I am glad that I took my own advice as I am aware that over 100,000 British Gas customers reportedly had failures within a one week period during last year’s big freeze due to the condensing boiler’s external pipe freezing.

'Instead, I spent £2,700 on sliding sash secondary glazing to insulate the existing single glazed wooden sash and case units which must remain under the area’s Conservation status.

'The effect was dramatic and well in excess of the benefits indicated by the SAP 2005/9 calculations. The heating consumption reduced immediately along with noise and condensation levels, whilst comfort was substantially increased due to a total lack of draughts.

'This small 62m² cottage has only consumed 10,350 units of gas over the last 12 months and I received a rebate of £130 from my energy supplier following the aftermath of the 2010/11 winter. As a comparison, I am aware of a similarly-sized property in the area that consumes 19,000 units of primary energy per year.

'My advice is that money should be spent on eliminating draughts and cutting heat losses by insulation and other methods in the first instance before investing in replacement boilers which tend not to last as long as their 1990s counterparts.'

The winner was chosen by public vote from a shortlist of five.

Photo by Elliott Brown

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2 comments - read them below or add one

Cathy Debenham

Cathy DebenhamComment left on: 22 December 2011 at 9:35 am

Brian asked me to post this response:

The secondary glazing system is sliding sash units that were purchased from Macleod Glazing of Perth and fitted by a local master carpenter, hence the £2,700 cost. However, unlike cheaper systems, they are robust and look very much part of the permanent fabric of the building. The secondary sliding sashes match the primary window openings so that they are almost invisible behind the wooden frames and they do not require to be removed in summer as with some other makes.

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Nick Hanna

Nick HannaComment left on: 21 December 2011 at 6:15 pm

Hi, I am interested in what kind of secondary glazing system was used please. I was looking at the EcoEase magnetic secondary glazing which is very cheap and was wondering what else might be comparable. Thanks. 

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