How to get double-glazing in Camden and Haringey’s listed homes

Grade II listed street in Kentish Town

Grade II listed street in Kentish Town - Credit: PA Archive/Press Association Images

As energy bills rise and environmental issues are pushed with increasing fervour, owners of listed homes can often feel they are receiving wildly conflicting advice.

Nowhere is this tension between conserving the built and the natural environment more fraught than in the deceptively simple issue of double glazing.

There are 5,600 listed buildings in Camden alone and large swathes of the borough and neighbouring Haringey are designated conservations areas, putting residents of Hampstead, Highgate and their surrounding neighbourhoods in a difficult position.

On the one hand, fitting new windows, or renovating existing ones is often promoted as an easy investment that will reap long term rewards such as a warmer house, reduced energy bills and lower carbon emissions.

As David Weatherall, energy efficiency expert at the Energy Saving Trust says, “by installing double glazing in an entirely single-glazed detached house you could save up to £175 each year.”

On the other, navigating the planning application process and obtaining permission to install double-glazing can prove difficult and confusing.

On top of that, the Listed Property Owner’s Club points out that 80% of owners of listed buildings fall into the lower economic bands B-D, with half in groups C-E, meaning that the cost heating single-glazed homes can be a real problem.

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Planning regulations for listed buildings and buildings within conservation areas are notorious for being extremely strict; English Heritage guidelines state that installing double glazing in any listed building is not acceptable.

However, Susan Rose, chair of the Highgate Conservation Area Advisory Committee says that restrictions may not be so tight in Camden and Haringey.

“It does depend on what sort of double-glazing you want. Provided you don’t change the appearance of the window it should be ok. Timber sash windows can be double-glazed without affecting the appearance. UPCV windows are a complete no-no though.

“People who live in listed buildings tend to understand this and want to preserve the character of the building. It’s more of a problem with the people who don’t have listed buildings but live in a conservation area as they will still have to apply for planning permission.”

It is worth bearing in mind that if replacement windows are allowed, options will be restricted as they will almost certainly need to use authentic materials and be designed to harmonise with the original design.

If owners are planning to repair, rather than replace, Haringey Council’s website recommends using modern secondary glazing units that are now available and are slim enough to fit in original Georgian window frames.

Double-glazing specialists the Box Sash Window Company also offer removable high-grade acrylic panels, which are not classed as fixtures but give better insulation than single glazing alone and reduce noise.

If you fail to get permission for any double glazing at all though – a possibility if the building has retained its original glass panes, for example – there are other options, which will still have a significant effect.

David Weatherall suggests draught-proofing. “It’s one of the cheapest and most efficient ways to save energy – and money – in any type of building.”