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Overview

Barratt Developments’ unique Zero Carbon concept home is located on the premises of Salford University and is the first house in the UK designed to showcase an “A to Z” of modern green home developments. SDS is one of 40 partners chosen to feature forward-looking sustainable technologies in the house, which is occupied and monitored to assess its performance. Outside the house a biodiversity garden includes nests for bats and swifts, a wildlife pond, hedgehog highways and a green wall.

Expertise from the RSPB has been sought to help promote wildlife and nature at the house, with the garden area achieving the organisation’s gold rating. The house has been constructed using the latest building methods incorporating Modern Methods of Construction (MMC) and features the latest sustainable housing technology, such as an air source heat pump, EV charging points, PV solar panels and battery storage. Cutting-edge devices and materials, including overhead infrared panels, that provide instant zero-carbon heat and new, airpowered showers, that cut water and heating bills, have also been installed.

In order to minimise the property’s consumption of mains water, with which to irrigate the property’s green wall and keep alive the plants, SDS was requested to equip the house with a smart rainwater recycling system.

What they did

Rainwater is channelled from the roof guttering and downpipe and collected in a tank via a leaf filter before being used to supply the green wall for as long as there is sufficient available. The system is programmed to deliver 4 litres of recycled rainwater to the wall every six hours when there has been no rain and there is no immediate prospect of rainfall above a pre-determined threshold; without it, the green wall would be reliant on potable water for its irrigation. Any excess rainwater remains in the tank for use elsewhere in the garden or to wash the car.

The project provides a live test bed for the adoption at scale of sustainable equipment and operating practices, with the primary objective to establish the capacity for a typical, average-size new build residential property to operate with a zero-carbon footprint.

The Results

Like many parts of the UK, Greater Manchester is faced with both increasing periods of heavy rainfall and also dry spells, so a simple downpipe-to-green wall irrigation system would drown the plants sometimes and bake them at others. SDS’s smart system maximises the use of the captured rainwater for regular, controlled irrigation, at the same time as reducing localised discharge which has the potential to impact on flooding in the immediate area.

As well as ensuring the plants in the wall remain watered, the introduction of rainwater harvesting can help both reduce flooding in the immediate vicinity in extreme rain events and potable water demand during dry periods – a double win for the natural environment.

Barratt has produced a series of videos to promote the Z House, the third of which features rainwater recycling and can be found at: https://www.youtube.com/watch?v=b22pkUTIbcg&t=535s