PowerPoint PresentationUK Passivhaus Awards 2013 Residence of the Austrian Ambassador, London 4th July 2013
Totnes Passivhaus Private Housing
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Project Overview
Type: Single family dwelling house with B&B
Build type: Cavity wall masonry retrofit using an External Wall Insulation System and a new-build timber-frame extension with living roof, natural and high performance materials.
Location: Totnes in South West England
Occupancy: Occupied since August 2011
Construction Costs: £1400/m² gross or £1475/m² net floor area
Totnes Passivhaus North Elevation
Project Overview
Project Team
Architect:
Consultants:
Certifier:
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Measured Energy Performance
Annual Heat Demand: 13.3kWh/m².a
Heating and cooling Load: 9W/m² heating 4W/m² cooling
Airtightness at Certification: 0.2 a.c.h.
Total Primary energy in use 76kWh/m² as measured in use
51kWh/m².a (electricity) 25kWh/m².a (gas)
This small uplift from predicted reflects both running a home office and the B&B
PROJECT ‘U’ VALUES:
Roof 0.1(average) W/m²K
Floor 0.2 W/m²K in retrofit 0.08 W/m²K in new-build
Windows 0.75-0.93 W/m²K
Doors 0.79 W/m²K
PROJECT FORM FACTOR:
This has a significant effect…
Typical range from say 2 to 4
VENTILATION STRATEGY:
‘Lindab Safe’ ducting
MVHR location
SHADING STRATEGY:
Helped with planning constraints, but milder climate
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Internal Environment
GLAZING
Lots of large windows ensure the house has a bright and light interior
– even on the north façade (the garden façade) we managed a large
fixed picture window.
INTERIOR TEMPERATURE is sensitive to the use of the integral
blinds – effective shading is essential. Temperature fluctuations happen
slowly, although 150 visitors at Totnes Eco Open House did have an
effect!
Initial problems with the in-line duct post heater meant that during the
first winter a small oil filled electric heater (400W) was used to heat the
three storeys to 19°C – imagine if this was NOT a Passivhaus…
During November 2011, while other nearby houses had already started
using their heating systems the Passivhaus windows were still being
opened - the ‘window opening season’ is definitely longer in a
Passivhaus
MVHR Filters are currently being changed every four months (an indicator
shows on the control unit located in stairwell) – only a five minute job.
The overall unit draws just 40W (circa 1KWh/day or 15p). The user
interface is not as ‘friendly’ as it could be, although mainly simply left on
the standard setting (its easier to open a window!). A lot of frying occurs
with the B&B and there has not been a need to boost the ventilation.
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Internal Environment
Occupant Feedback Suzanne & David, London, Nov 2012
“Thank you for your warm hospitality and for
being our first real experience of a passive
house – very inspirational!”
“Thank you for a great stay in a wonderfully
designed Passivhaus. It has been inspirational!”
Bruce H. & Sarah W., January 2012 “Amazing Passivhaus!” “Great place – all houses
should be like this! Thanks for the warm,
friendly welcome.”
Jonathan & Susie P., Devon, Jan 2012 “Wow. What a comfortable experience!
We will be back for more. Thank you”
“Such a comfy bed and delightful view;
so grateful to experience Passivhaus in reality!”
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Design Philosophy/ Innovation
The house forms part of a 1970s modernist estate so the design had to address the perceived ‘group value’. Overhanging eaves or prominent shading devices were not acceptable to the planners and the roof form, orientation and finish result from the context.
We used a combination of high performance materials (as dictated by the performance needs of the retrofit) and a ‘natural materials’ led design for the new-build element.
Estate architect was LEONARD MANASSEH and is referenced by PEVSNER two or three times
The original dwelling Adjacent dwellings, group value & style
Totnes Passivhaus
Design Philosophy/ Innovation
Totnes Passivhaus – Passivhaus Homes Ltd.
Aesthetics – part of a 1970’s modernist estate where the ‘group’ value needed to be maintained
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Aesthetics
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Other sustainability features
Living Roof
The new timber-frame extension has a living roof which was modelled in WUFI by Ecological Building Systems to ensure any potential condensation issues were addressed for a timber and highly insulated envelope…
Solar Hot Water and PV Array
Photovoltaics – Moboasolar panels, total 3.99kWp, Fronius IG TL transformerless inverter; solar hot water – Rotex 500 litre thermal store with 9.4m² of integrated roof panels
East and west
facing – loss in
Costs
Extra construction costs
Extra over Adam estimated at 10% covering uplift for Passivhaus specific items such as high specification windows
Planning costs
There were costs relating to re-working to suit the planning constraints – orientation, windows, shading
More than half total spend in local and SW
England economy
Outcomes…
The Passivhaus Handbook The project demonstrated the importance of effective team-working and finding common goals
and the need for a practical and accessible book on the subject, now realised through Green Books.
‘Could not think of a better book to cover this subject. Well thought out.
Well written. Useful illustrations. Excellent tables and specific interest
segments.’ M.H. Denekamp, June 2013
‘This book is very informative without being too technical, so suits
professionals as well as those considering commissioning a Passivhaus
design. Highly recommended.’ Martin Smart, April 2013
Optimised Timber Portal Frame System Simplified for affordable new-build – first prototype
air tight test next week (July 2013). Options PH15 and PH30
Adam’s PROJECT BLOG A great online resource and continues to receive positive feedback from Passivhaus enthusiasts. http://passivhausrefurb.blogspot.co.uk