Retrofit of Victorian terrace house reduces energy bills by 89%
Posted by Cathy Debenham on 20 April 2012 at 7:38 am
Described as a "labour of love" by designers Green Tomato Energy the conversion of a Victorian mid-terrace, built in approximately 1870 with solid brick walls, to PassivHaus standard has significantly improved comfort and reduced energy bills.
Due to planning restrictions in the local conservation area, the exterior of the house had to be kept unchanged in appearance. As such, all insulation was applied internally on floors, walls
and ceilings, with floor joists rehung to avoid penetration of the insulation. The renovation works were used as an opportunity to redecorate the interior, remedy structural defects in the fabric and extend the house at ground and third floor levels.
- Ground-to-air heat exchanger below existing basement floor
- Integrated solar thermal system for hot water, backed up by air-source heat pump
- Exhaust-air heat pump inside ventilation system for all space heating
- Green roof
- Specially designed triple-glazed sash imitation windows for conservation area
- Thermal bridges cut off by extensive detailing and rehanging of floors
Metered energy use for the first six months of occupation was 1.78MWh (including space heating, DHW, auxiliary and household electricity). Projected forwards, this gives an annual energy consumption of approximately 5.35MWh, or a saving of 89% against the most recent metered energy consumption from the house before the
The values above correspond to a PassivHouse specific primary energy demand of 54.8kWh/m2a. This is well below the predicted energy consumption, despite the presence of a baby and young child (and hence very intensive use of the washing machine). Close monitoring of the house continues.
The user experiences are overwhelmingly positive and the owner describes the house as a “fabulous living environment… exceptionally comfortable”.By Cathy Debenham
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