Lark Rise Passivhaus Plus house

  • by Laura Davila
  • /
  • 2018-06-06 13:53:55
  • /
  • Internazionale
  • /
  • 7421 / EN
  • Building Type : Isolated or semi-detached house
  • Construction Year : 2014
  • Delivery year : 2015
  • Address 1 - street : HP17 0XS AYELSBURY, United Kingdom
  • Climate zone : [Cfb] Marine Mild Winter, warm summer, no dry season.

  • Net Floor Area : 175 m2
  • Construction/refurbishment cost : 1 200 000 €
  • Cost/m2 : 6857.14 €/m2

Proposed by :

Certifications :

  • Primary energy need :
    80 kWhpe/m2.year
    (Calculation method : Other )
Energy consumption
Economical buildingBuilding
< 50A
51 à 90B
91 à 150C
151 à 230D
231 à 330E
331 à 450F
> 450G
Energy-intensive building

Lark Rise, the first Passivhaus Plus building in the UK, was rigurously designed and built by Bere Architecs in 2015 to test the viability of the concept ‘house as power station’ in a north European climate and to establish the potential for a cluster of similar houses to draw down energy from the National Grid.

Lark Rise is an ultra-low-energy, all-electric, contemporary and healthy certified Passivhaus Plus home. It is a detached two-storey, two-bedroom dwelling of 175m2 located on a North West facing slope on the edge of the Chiltern Hills in Buckinghamshire, England. It is partially prefabricated with heavyweight reinforced concrete retaining construction system to ground floor at garden level and prefabricated timber frame structure to first and floor at entrance level. 

The main garden façade faces North West and is entirely glazed, with large windows and a terrace. Solar gains are limited because most of the glazing faces to the North West. Partially underground construction to reduce visual impact on a protected landscape area and northerly orientation certainly help to maintain stable and comfortable temperatures in Summer and Winter and help avoid summer overheating.

The house has been provided with a PV system on the roof designed to generate 12.4 kWp by means of 38 PV panels. The energy consumption and PV production data have been monitored and analysed for 1-year period between Oct-16 and Sep-17 and compared to a UK standard house and other Passivhaus projects achieving outstanding results.

Fully operational (with 13kWh battery storage), Lark Rise is expected to draw from the grid only 2% of the energy a similar sized standard UK house each year, while exporting 10 times this amount back to the grid each year.

See more details about this project

Data reliability

3rd part certified


    Sandwood Construction Ltd.

    Richard Garland

Construction Manager

    Bere Architects

    Justin Bere (


    Certification company


    Kym Mead (

    Passivhaus Plus Certification

    Environmental consultancy


    Environmental Engineers that carried out the self-consumption analysis

Contracting method

General Contractor

Owner approach of sustainability

One is a scientist, the other a medic. Both were interested in going somewhat further than the minimum requirements of the building regulations in order to create a prototype all-electric, plus-energy, grid-connected, low carbon building that might show how buildings can provide community infrastructure benefits as well as benefits for the occupants.

Architectural description

Lark Rise is an ultra-low-energy, contemporaryand healthy home. It is a detached two-storey, two-bedroom dwelling of 175m2located on a North West facing slope on the edge of the Chiltern Hills inBuckinghamshire, England. The main entrance is on the upper floor, facingtowards a sheltered entrance forecourt to the South East. The main views are tothe North West from the upper floor reception spaces, and from the bedrooms onthe lower floor. The garden consists of a level lawn, overlooking a smallorchard and rolling farmland that extends as far as the eye can see. The upperfloor contains an entrance area, cloakroom, and open-plan kitchen/living space,and the lower floor contains two bedrooms, two bathrooms, a boot room, and autility room.

The main garden façade faces North Westand is entirely glazed, with large windows and a terrace. Solar gains arelimited because most of the glazing faces to the North West. Partiallyunderground construction to reduce visual impact on a protected landscape areaand northerly orientation certainly help to maintain stable and comfortabletemperatures in Summer and Winter and help avoid summer overheating.

If you had to do it again?

We are doing it again for another client, using low-cost construction on a level site at 1/3rd of the cost.

Building users opinion

Very happy that the house is gaining so much interest around the world as a pioneering example that might one day be the norm.

Energy consumption

  • 80,00 kWhpe/m2.year
  • 200,00 kWhpe/m2.year
  • Other

  • 42,00 kWhfe/m2.year
  • Heating: 22%
    DHW: 10%
    MVHR: 9%
    Power sockets: 25%
    Cooking: 5%
    Miscellaneous: 9%
    Lighting: 19%

    Lark Rise consumption was monitored during 2 tenancy periods, user preferences can cause variations in the floating demand seen in the cooking and lighting levels, however, we would expect the miscellaneous circuit to show a relatively constant demand between tenancies because the circuits which are fed by the ‘miscellaneous’ submeter shouldn’t be greatly affected by user preference, however there was an unexpected consumption on the 'miscellaneous' circuit (pumps etc) during the second tenancy period. At present the cause of the variation in miscellaneous power demand is not known. However, the pump within the septic tank burnt out in November 2017, and it is possible that the increased consumption could be due to this.

Envelope performance

  • 0,12 W.m-2.K-1
  • •Below ground walls: concrete basement retaining structure (250mm), exterior Foamed glass insulation (360mm). U-value= 0.118 W/(m2K)
    •Above ground walls: Prefabricated timber frame, with mineral wool insulation (300mm), and larch rain screen cladding. U-value = 0.137 W/(m2K)
    •Prefabricated Glulam box-beam ceiling, PIR insulation (280mm) and multi-ply hot-melt membrane, extensive green multi-ply bituminous membrane roof. U-value= 0.074 W/(m2K)
    •PUR insulation (50mm) and screed with UFH and floor finishes on top of concrete slab (300mm) and foamed glass insulation below-slab (410mm) U-value= 0.076 W/(m2K)
    •Passive House certified, insulated triple-glazed timber-framed windows & doors. Ug= 0.60 W/(m2K), Uf= 0.72 W/(m2K), g-value= 62%
    •Entrance door: Bayer Passive House insulated timber-framed door. U-value = 0.81 W/(m2K)

  • 0,21
  • n50

  • 0,41
  • It's an incredibly simple and robust building in use. 

Real final energy consumption



    2 016


    • Heat pump
    • Heat pump
    • No cooling system
    • Natural ventilation
    • Nocturnal Over ventilation
    • Double flow heat exchanger
    • Solar photovoltaic
    • Heat pump
  • 200,00 %
  • Zehnder, Paul Novus 300
    eff. specif. HRE: 91%
    Maximum flow rate [m³/h] 300
    Electric power input [W] 90
    Sound power level [dB(A)] 43
    Reference flow rate [m³/h] 210
    Reference pressure difference [Pa] 50
    SPI [W/(m³/h)] 0,22
    heat exchanger

    12kWp PV installation on the roof with a 13kWh battery store

    Since most of the glazing is sub-optimally oriented to face North West, it needed to be made from super-clear glass with a high g-value in order to maximise winter heat gains

Smart Building

    Very simply that the heat pump will heat the hot water to a few degrees above set temperature if there is excess sun.
    The building use, PV production, battery storage and import or export can be seen in real time via the Tesla application on a mobile phone. This information is being used to tune the building and to decide what the next steps might be (e.g demand shifting or change of user habits eg switching off lights and IT and gaming equipment on standby.)

    not yet applicable, but may follow

    Interested in viewing the information provided by the Tesla app.

GHG emissions

  • 16,00 KgCO2/m2/year
  • Indirect emissions from electrical power consumption are estimated in PHPP through the use of electrical emission coefficients in Germany (GEMIS)

Life Cycle Analysis

    This is a very interesting topic, but not yet assessed for this building. On another similar project, but with 1/4 the generating capacity, we found that the embodied energy from the building's construction could be paid back in 60 years. This building is


Water management

    All waste water is processed on site using a low energy septic tank and zero energy natural water polishing system based on natural bacteria in a peat store.

Indoor Air quality

    Other similar projects of ours have been independently monitored, tested and assessed with the conclusion that they provide optimal conditions with optimal RH generally around 40% with any peaks being flushed away within an hour by the heat recovery ventilation system. CO2 levels have been found to be optimal, generally between ambient external conditions and an upper level on occasions no greater than 1000ppm. F8 incoming filters have been found to control incoming pollen and particulates. Healthy construction using natural materials has been found in another project to result in a very low VOC count, both from the building construction materials and from household products.

Health & Comfort

    The above indoor air and humidity conditions contribute to very healthy and comfortable conditions. Also both summer and winter temperatures have been found to be very comfortable, with negligible seasonal, daily or hourly fluctuations.



    21 degrees centigrade in summer and winter

    approx 21 degrees centigrade in summer and winter

    The concrete construction with first floor screed floating on XPS insulation makes for an extremely comfortable acoustic condition.


    LIGNO TREND Roof system


    Ralf Harder (

    Opere strutturali / Tamponamento, Rivestimento, Tenuta

    Load-bearing insulated CLT ceiling component


    Kaufmann Zimmerei und Tischlerei, Reuthe, Austria - first floor timber frame structure and finishes.

    Shoeck Isolators for balcony connections

Urban environment


Building Environmental Quality

  • indoor air quality and health
  • biodiversity
  • acoustics
  • comfort (visual, olfactive, thermal)
  • water management
  • energy efficiency
  • renewable energies
  • maintenance
  • integration in the land
  • building process
  • products and materials

Contest categories

Energy & Temperate Climates

Energy & Temperate Climates

Low Carbon

Low Carbon

Health & Comfort

Health & Comfort

Users' Choice

Users' Choice

Green Solutions Awards 2018 - Buildings

Author of the page

  • Laura Davila


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