TUV SUD Wallace Whittle (TSWW) have completed their first ‘zero carbon’ dwellings for client and developer Lend Lease. An idea of the TSWW Sustainability Team of designing to zero carbon Building Regulations in 2012/13 was complete in June 2015 when the final air permeability testing was carried out for the 102 apartment and 2 townhouse scheme, in Wandsworth, London. Both townhouses secured minus figures in Dwelling Emissions Rate (DER) through a variety of measures and achieved the goal of zero carbon whilst maintaining a ‘normal’ townhouse appearance for a Central London location.
The townhouses have been built with extremely low U-values, including triple glazing throughout. The glazing is sized and orientated to allow good levels of natural daylight without compromising the dwellings thermal performance. The Cross Laminated Timber (CLT) structure assisted in reducing the air permeability of the dwellings, virtually minimising the requirement for space heating. Thermal bridging calculations were undertaken demonstrating low y-values and good construction methodologies for minimising heat loss. The heat and hot water is provided from a utility cupboard which is connected to the schemes centralised network, which not only provides heat to the apartment block but also to the local school. The centralised heat network is fed by a modulating Combined Heat and Power (CHP) engine and backed with highly efficient gas fired condensing boilers. All the lighting is dedicated to LED fittings.
Both townhouses include a 3 kWp Solar Photovoltaic (PV) on the dwellings roof. The PV has been hidden below the parapet as a request of the Local Planning Authority but sufficiently designed and built to compromise any overshading effect by raising the PV frame and slight tilting to optimise performance. Both townhouses have secured 100 ‘A’ rated Energy Performance Certificates (EPCs) and are on track to securing Code for Sustainable Homes Level 5 accreditation.