Tomorrow’s home today
The government's proposal that all new homes should be zero-carbon rated by
2016 has set a tough target for housebuilders in terms of design, delivery and affordability. Gary Mills reports on a new development which addresses these issues
The built environment has a major role to play in achieving the 60% reduction in emission targets boldly announced in April in the draft climate change bill.
How we use and operate our buildings has a huge impact on the emission levels of the UK, and it is right they are a focus of targets to reduce CO2 outputs.
Indeed, buildings were identified as one key area where emissions can be cut when the bill was published – not only in how they must use energy more efficiently, but in how they are designed, constructed and lived in.
While all building types must respond to this precedent, the house building sector has been handed an additional challenge with the government announcement that all new homes built must be carbon-neutral by 2016. It is the clearest sign yet that the government is determined to reduce emissions in the housing stock.
Consideration of some of the issues involved here demonstrates the enormity of the task. The built environment accounts for 50% of the UK’s emissions – housing alone accounts for 25%. Construction materials contribute a further 10% of total carbon emissions, and the industry produces a third of all waste: 31m tonnes each year, equivalent to one tonne per household.
In order to hit its targets, the government has adopted a carrot and stick approach, tightening building regulations over the next decade to improve the energy efficiency of new homes. It has proposed a new Planning Policy Statement on climate change to take into account carbon emissions. And it has published the Code for Sustainable Homes, which includes a green-star rating for properties. The carrot for homebuyers comes in the form of a commitment to exempt zero-carbon homes from stamp duty.
While the technology exists to achieve the 2016 target, making these new homes affordable and sustainable in less than a decade presents a huge challenge for housebuilders.
The issues are legion, from design and supply, to affordability and particularly deliverability if housebuilders are to attain the 200,000 units per year. This is the figure required to tackle the current housing shortage. And all this is before even considering creating homes that people actually want to live in.
It is in the face of challenges such as these that our Upton C development, currently under construction in Northampton, can provide a solution and lessons for future housing design.
Upton Site C is part of a major urban extension in collaboration with English Partnerships, Northampton Borough Council and The Prince’s Trust. In what could be considered by some as something of an accolade in eco-housing, a computer-generated image of the Upton site is on the front cover of the government’s Code for Sustainable Homes.
Site C was the third release of land for development at Upton, and comprises 30 new detached and semi-detached homes all equipped with a range of state-of-the-art Eco home amenities. These ensure minimisation of water usage, reduced carbon emissions, and use of renewable energy sources in line with sustainable guidelines.
It is expected that all of the homes at Upton Site C will achieve an Eco homes Excellent Standard.
English Partnerships produced a detailed design code for Upton during the tendering process, which specified a clear vision for the site and for the chosen developer to follow.
The challenge for us was to design and build homes which conformed with the design codes and provided homes where people would actually want to live. It is also important to prove that housebuilders can build sustainable urban neighbourhoods for the 21st century.
In collaboration with HTA the architectural consultants, we designed and are using
17 different house types at Upton. This demand detailed consideration of the local
housing vernacular to ensure that we incorporated Northamptonshire heritage, such as the one-room-deep house and the inhabited roof, into the Upton design.
In terms of actual design, each property has a double-height solar space and pitched roofs at variable heights to maximise access to sunlight. The development also optimises building orientation by analysing sunpaths, ensuring maximum window area to the south and by avoiding overshadowing. Landscaping and its implications on the building’s exposure to wind and solar radiation have also been taken into account to ensure properties are sensitive to the local climate and wind direction.
The end result is that each home is designed to maximise natural light and solar power gain, which feeds the solar collectors for the heating and hot-water systems. Upton also includes photovoltaic systems, which provide power for the houses with any excess sold back to the national grid. The key point about Upton is that all of this equipment is designed in to the fabric of the building, not retrofitted as an afterthought.
In addition, each home is equipped with high-efficiency boilers to minimise energy usage along with rainwater harvesting equipment to minimise water usage. Green roofs were also incorporated into the designs of a number of individual properties to aid more efficient retention of stormwater and also water attenuation.
All green roofs are irrigated by rainwater harvesting tanks.
Below ground, the entire site uses sustainable urban drainage systems, which promote the capture and attenuation of water.
While Upton certainly breaks new ground in sustainable design and construction, innovation such as this does come at a premium.
The real proof of popularity will come the homes go on sale and people actually have to put down a deposit. There is an important lesson here: design and consumer appeal must continue to be at the forefront of eco-developments to create a wow factor that makes them stand out from conventional housing.
Estimates suggested by the Department for Communities and Local Government in its recent report, Building a Greener Future, suggest that the costs of building a home that is 44% more energy efficient than today – the standard it wants all home to achieve by 2013 – would be 4% to 7% higher than for a conventional home.
This will be difficult to pass on to the purchaser. There has to be something in it for them and the wow factor appeal of superb design could be part of the incentive.
Upton is very different from usual housing design. And we have learned a lot about sustainable design and construction, which we are already incorporating into our more mainstream designs.
Schemes like this are invaluable to start the ball rolling in sustainable development. But to achieve the carbon-neutral future envisioned by the government, the thinking must extend beyond individual schemes to community-wide developments of several thousand homes.
Home design and construction is crucial. But how we travel around our communities, reduce and recycle our waste, communicate and interact with one another will shape our town and cities in the coming decades.
Gary Mills is regional chairman of David Wilson Homes.
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