Introduction
Situated in the London Borough of Camden, the Camden Passivhaus achieves the UK’s 2016 zero carbon compliance standard. It was bere:architects’ first certified passivhaus, and also London’s first passivhaus. Bere:architects used this project as a vehicle to learn about advanced, thermally-efficient European timber frame techniques; by means of an 18 month knowledge transfer exercise, with Matthias Kaufmann of Kaufmann Zimmerei who joined the office in 2008. The Camden Passivhaus acted as a ‘test-bed’ for bere:architects’ Welsh-made passivhaus social housing prototypes.
The fabric and in-use performance of the Camden Passivhaus has been independently monitored in collaboration with University College London and funded by the UK Government’s Technology Strategy Board as part of the Building Performance Evaluation programme.
Detailed monitoring of the Camden Passivhaus by University College London, has found that passivhaus techniques have resulted in a comfortable and healthy home for the client’s young family, and is showing that the building is performing even better than designed. The Arup BUS occupant survey found it to have an extremely high user approval rating compared with other low energy houses officially tested using the BUS methodology. This is all the more remarkable when one considers that the occupant did not commission the house and does not have any real interest in the passivhaus standard other than the comfort she enjoys and the health benefits she has experienced.
Fabric Performance Data
The fabric performance of the house has been analysed with blower door air pressure tests, co-heating tests, tracer gas tests, in-situ U-value heat flux measurements, infra-red thermography, thermal bridge analysis and a forensic review of all of the building systems over the course of 2011.
The blower door test result was 0.44h-1 ACH @50Pa this surpassed the 0.6h-1 ACH @50Pa which is the requirement for Passivhaus projects. The tracer gas test (CO2 decay) calculated a value of 0.38 ±0.08h-1.
The co-heating test result showed performance is even better than design. The total heat loss for both ventilation and fabric losses was measured to be 35±15W/K, compared to a design target of 63.6W/K, although the weather conditions for the test were not ideal and it is hoped to repeat the test this winter.
Heat flux sensors were placed on an interior wall and floor to measure the heat flux through the fabric and therefore measure the respective u-values. The flux measured on the ground slab was 0.099±0.013 W/m2K, compared to a design target of 0.103W/m2K. The flux measured on the lower wall was 0.097±0.020 W/m2K, compared to a design target of 0.122W/m2K.
These tests all showed that the Passivhaus standard has delivered a building which has outperformed its design data, a fact that is unusual in the UK. bere:architects and their independent teams have measured similar results in all of their other Passivhuas projects.
In-use Data
The university monitoring began in July 2011 and is ongoing. It involves submetering of electric, gas and water utilities to analyse the energy use. The monitoring also looks at the efficiency of the heat recovery unit, air heating and solar hot water systems.
The monitoring shows that the maximum CO2 in the bedroom is