Miller Zero, The Pinnacle, Basingstoke, Hampshire

15/9/2009

The UK‘s sixth largest housebuilder has demonstrated the challenges involved in the move to zero carbon by developing a set of homes to level 1, 3, 4, 5 and 6 of the Code for Sustainable Homes.

Description

Five four bedroom houses at The Pinnacle site in Basingstoke have the numbers 1 to 5 boldly marked on each kitchen window. Were it not for this, potential buyers coming onto the site would not be aware that there is anything more sustainable about these houses than any of the other white rendered contemporary designed homes on the development.

Miller Homes chose to use this site for Miller Zero, its trial of the Code for Sustainable Homes, because the layout and design of the homes had already been set, and therefore represented today‘s norm. Miller Homes acquired the site through a design competition by Hampshire County Council, working with architect Fraser Brown McKenna on the initial design and then adapting it in house. All homes on the site meet the government Lifetime Homes policy, which will be compulsory from 2013.

The homes allow the housebuilder to not only test design and construction, but also marketing and performance. Homes are priced to reflect their environmental features, with the level 1 home on sale at £305,950 and prices ranging up to the level 6 home at £339,950. Once occupied, the homes will be monitored for a year.

Key innovations

• Level 1 house: this serves largely as a benchmark, but incorporates mechanical ventilation with heat recovery (MVHR) and smart meter.
• Level 3 house: has MVHR, smart meter, water saving sanitaryware, air source heat pump (ASHP), and is built using thin joint masonry.
• Level 4 house: has MVHR, smart meter, water saving sanitaryware, thin joint masonry walls, ground source heat pump (GSHP) with two 90m deep boreholes, and underfloor heating
• Level 5 house: has MVHR, triple glazed windows, smart meter, water saving sanitaryware and appliances, 14m² of photovoltaics, rainwater harvesting via a 200 litre tank for reuse in toilets and washing machines, biomass boiler and was constructed from Kingspan TEK Structural Insulated Panels (SIPs).
• Level 6 house: MVHR, smart meter, water saving sanitaryware and appliances, underfloor heating, approximately double the quantity of photovoltaics of the level 5 house, rainwater harvesting, biomass boiler, full storey height Aircrete panels and external insulation of 300mm urethane foam and render.

Learning points

• The housebuilder worked to minimise the visual impact of the technology. Pipework is boxed in, the cupboard under the stairs houses manifolds and photovoltaic array read out, and the washing machine is in a utility room at the rear of the house, with a short connection to the greywater tank.
• The housebuilder used hollow web floor joists. Ian Beal, managing director with Miller Homes (Midlands and South), believes their use will become more common in housebuilding to accommodate the increased amount of servicing.
• The housebuilder hopes to try different approaches on ecology. Beal says: “We put in bat and bird boxes, but in the middle of this site it was pure point scoring. We'd like to be having conversations about ecology earlier so that we can do something appropriate sitewise rather than tick a box for a plot.”
• The site was set to have a wind turbine, but the planners refused permission.
• The level 6 house cost £50,000 extra, even though the housebuilder innovated to try to cut costs. For example, it was unable to source PVCu triple glazed windows in the UK, and so worked with LB Plastics which developed a new product. Tim Hough, chief executive of Miller Homes says: “It saved us significant cost, but it was frustrating that we had to do it. It would have been better if the conversations with the window manufacturers had taken place when U values were set.”
• Hough says: “Many of the design guidelines and regulations applied here compete and do not talk to each other. We would like to get guidance pulled together in a form that is clear and concise.”
• Hough concludes: “I am not convinced homeowners should be running a mini power station. We need more engagement with power providers on how to provide energy on a site or area wide basis.”

Sources and links

For more information on the project, go to: www.millerhomes.co.uk/millerzero.