This week Kevin McCloud returned to the Hedgehog Project in Brighton on Grand Designs and showed how that housing co-operative has moved on from being an innovative self-build to building roots in the community – reflecting our experience here at Hockerton Housing Project.
We are hoping that the planners at Newark and Sherwood will have been watching, as a plan for a new self-build partnership in Hockerton is now under consideration. The plan is to demolish a redundant industrial building and replace it with five two-storey homes (up to 3 bedrooms) and two one-storey, one bed homes.
Hockerton Housing Project is supportive of the plans for a number of reasons:
The energy efficient design will deliver 80% less carbon and 60% lower running cost than homes built to today’s minimum standards.
Each dwelling will have a share in Hockerton’s community-owned wind turbine to ‘offset’ the carbon content of remaining energy use.
Rainwater harvesting and water efficient appliances will limit demand for mains water, and a reedbed will be used to avoid nasty odours from sewage.
Affordable housing allows people with a wider range of skills and expertise to live in rural areas.
The co-operative nature of the development, both in its build and its maintenance, means pride will be taken in the quality of the work on buildings and landscaping.
The more people resident in the village, the better for local businesses such as the farm shop, the pub, restaurant and ice-cream parlour.
Self-build partnerships are rare, but offer many benefits, so let’s hope the planning officials see the merit of putting brownfield land to better use as a site for new affordable homes in Hockerton, further strengthening the village’s reputation as a hub of innovative and affordable energy efficient homes.
If you are interested in understanding how we developed our self-build at Hockerton Housing Project, and how the co-operative works in practice, make a new year’s resolution to come on one of our Sustainable Living Tours – the next one is 19 January 2013.
Yesterday the Government launched its Energy Efficiency Strategy, and we were particularly interested to see if any mention was given to the role of SAP, the Government’s energy performance assessment tool.
Hockerton Housing Project takes pride in its low-tech, low-cost approach, and the homes consume 15-25% of the energy used by homes built today. But the Government’s energy efficiency measurement assessment tools (SAP and RdSAP) cannot compute the benefit of homes like ours:
SAP cannot cater for our use of passive solar gain as our main heating system
Use of thermal mass to reduce heat demand through the year is not recognised (the thermal mass in our homes essentially stores the summer heat and keeps our homes warm in winter)
SAP assumes that an element of mass thicker than 100mm has no additional thermal capacity is flawed (SAP2009 Table 1e: Heat capacities for some common constructions), contrary to evidence at HHP. As long as the mass is well insulated (externally) the full thickness of the mass will be effective as a heat sink.
RdSAP does not differentiate between internal and external solid wall insulation, so the benefits of external insulation to “lock in” the mass of the walls, which can then aid summer cooling and winter heating, are not recognised for existing dwellings.
SAP assumes that thermally separate conservatories are not present, ignoring two benefits:
The sunspace provides sheltering of the dwelling from the external environment, therefore reducing heat losses.
The sunspace can be used to harvest passive solar energy which can then be brought into the main dwelling to top-up the heat stored in the thermal mass as required.
All this matters because the Government tells us in the Strategy that it intends to make more policies conditional on energy efficiency. Access to feed-in tariffs and the renewable heat incentive are already affected, and RdSAP or EPC ratings could also be used to introduce differential council tax or stamp duty. All this will mean that energy efficiency improvements will be made to meet whatever measure of energy efficiency is applied. Whilst a policy to drive up the value of energy efficiency in the property market would be very welcome, as this is potentially the simplest way to drive investment in existing homes, this must not be so broad-brush as to drive out innovative approaches and a process for ‘exceptions-handling’ must be incorporated into future policies.
Seeing is believing
On the upside, whatever documents come out of Westminster, here at Hockerton we’re enjoying ‘zero’ energy bills as our investment in additional solar PV starts to pay off and the summer heat stored in our thermal mass continues to keep our homes warm.
If you are interested in homes that are comfortable yet consume only 15-25% of the energy used by homes built today, this time of year is the best time to visit to truly feel the difference. There are some spaces left on the tour this coming Saturday 17 November so book your place on a tour of Hockerton Housing Project here.
Work has started on a new earth-sheltered, self-built development in Hockerton, Nottinghamshire. The two homes will be developed in a 1-acre field adjacent to the Hockerton Housing Project (HHP) site. Although planning was not straightforward permission has been achieved as a result of the clear environmental design and strong association with HHP. This again represents the forward thinking nature of Newark & Sherwood District Council, who are clearly near the forefront of facilitating sustainable development in the UK.
The design is led by HHP project member/builder, Nick Martin, with significant input from the commissioning parties.
The earth-sheltered homes will be highly energy-efficient with super-insulation, high specification glazing and south facing conservatories designed to collect heat from solar radiation in colder months. The high thermal mass of the buildings combined with insulation means that the homes will be zero-heating, with all heating needs met by solar gain and incidental gains from living in the building. The homes will collect their own water using a rainwater collection system (FreeRain), and waste water will be treated on site via a reed bed system.
There will be close links with HHP including reciprocal assistance with land management, food-growing activities and maintenance of water and energy systems.