This page will be periodically updated as data becomes available. Figures quoted are from calculated (c), estimated (e), measured (m), or certified (x) values, as stated.
|Windows||2.4 to 3.2 (e)1||0.9 (x)||W/m2 K|
|Doors||3.6 (e)||0.9 (x)||W/m2 K|
|Existing Walls||1.4 to 1.6 (c)||0.12 to 0.17² (c)||W/m2 K|
|Extension Walls||N/A||0.14 (c)||W/m2 K|
|Pitched Roof||0.7 (c)||0.10 (c)||W/m2 K|
|Concrete Flat Roof||4.65||0.14 (c)||W/m2 K|
|Extension Sedum Roof||N/A||0.14 (c)||W/m2 K|
|Ply Flat Roof||3.0 (c)||N/A||W/m2 K|
|Air Permeability||18.4 (m)||1.78 (m)³||m3.h-1.m-2 @50Pa|
|Heat Loss Coefficient||840 (c)||163 (c)||W/K|
|Heat Loss Parameter||5.42 (c)||0.73 (c)||W/m2 K|
|CO2 EMISSIONS||11,575 (c)||2,040 (c)||Kg/yr|
1. Reflects the varied ages of double glazed units, estimated using SAP 2009 data
2. Existing walls with external wall insulation (approx 90% of available wall area) will be 0.12 W/m2 K; some small areas, e.g. existing retaining walls, can only be insulated internally, where the U-value will be 0.17 W/m2 K.
3. Target was <2.0 m3.h-1.m-2 @50Pa. There is still some potential to improve upon the tested value in the table.
Energy consumption of the existing house as measured during 2010/2011 was 4,155 kWh/yr for electricity and 24,500 kWh/yr for gas, which serves space heating and hot water. Estimating the amount of gas used for space heating equates to approximately 145 kWh/m²/yr. By comparison, low energy standards, such as Passivhaus, requires the specific energy used for space heating should be no more than 15 kWh/m²/yr. The Passivhaus retrofit standard (EnerPHit), allows a slightly more relaxed 25 kWh/m²/yr. This means that we have to reduce the energy currently used for space heating by some 85% – a considerable challenge.