22 January 2019 The FIfth Estate’s David Thorpe: Graphene stars in Passivhaus retrofit of Victorian townhouses

22 January 2019 by Jason Quinn

Great article but horrible title. The wonder material graphene is added to the paint as an anti-cracking additive. Neat but totally doesn’t impact the performance of this Passivhaus. Also great to hear of more UK projects that are being delivered at market rate cost.

I’d love to have seen some discussion on how they dealt with the thermal bridging back to the heavily insulated sidewalls or the type of interior insulation. Often in the UK projects like to use Vacuum Insulated Panels (VIP) which are an aerogel in a vacuum as the insulation on the interior to not shrink the internal floor area.

Now VIP is a wonder material worthy of a title mention. They put aerogel in a aluminum foil back and suck out all of the air – resulting in a thermal conductivity of 0.005 W/(mK) when manufactured and 0.019 W/(mK) when you’ve accidentally put a nail in it and let air into the package. To understand how incredibly awesome that is you have the insulation of 80mm of fiberglass batts in only 10mm of thickness (R1.4). It used to be very expensive and I’d only seen it used in Yacht refrigerators but in the past 5-6 years the price has dropped and it is reasonably common in Passive House EnerPHit retrofits in Europe. See www.porextherm.com for more details.

“He added that the costs of all the technologies used in the houses are dropping. “A new UK program based in Norwich has managed to build 100 Passivhaus units for the same price as normal new build houses,” he pointed out.”

“Passivhaus refits are becoming more affordable
It’s often said that the cost of a deep retrofit to Passivhaus standard of an old house is prohibitive – around £60,000 [AUD$107,751].
In response, founder of Ecospheric Kit Knowles said: “True, but as homeowners will generally use the opportunity of a deep retrofit to also install new kitchens, bathrooms and extensions, the typical spend for such a project is often double that – up to £160,000 [AUD$287,336]. This means for an average £250,000 [AUD$448,963] house, the costs for retrofitting are around 25 to 50 per cent of the value of the building. Of course, as the property value increases, so that percentage drops. Also, the cost savings achieved by passive houses continue forever.””

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