Energy Efficient Homes
The English and Scottish governments are introducing phased energy efficiency standards for new homes. The Future Homes Standard in England is phasing
in standards that will phase out fossil fuel heating by 2025 and seek a 75-80% reduction in energy use, allowing homes to become zero carbon once the electricity grid is decarbonised. Scotland has similar measures to be implemented by 2024.
This will be included in the Building Regulations. Communities can press for higher standards to address the climate emergency and to improve the comfort and affordability of individual dwellings. One of the most widely used is Passive House which uses a combination of insulation, renewable energy, airtightness and ventilation to reduce energy demands by 90% compared to a typical dwelling.
Neighbourhood Energy Strategies
Energy use can also be addressed at the neighbourhood scale, and Scotland is currently introducing legislation to promote local heat networks. Local energy master plans include the ‘retrofit’ of existing properties to make them more energy efficient either through landlords or assistance to individual householders. They can also include renewable energy such as air, water and ground source heat pumps, photovoltaic panels, wind and even low-speed hydroelectric power (if you have a suitable watercourse). These can be combined to create decentralised low-carbon energy systems providing local heat and power, balancing supply and demand at the local level, managed by communities using IT infrastructure.
It is important to think about the environmental impact of construction. Embodied energy refers to the energy used in the construction, maintenance, refurbishment and demolition of buildings. It accounts for 40% of a building’s total carbon emissions rising to 70% in ultra- low energy buildings. Advice by LETI suggests we should be targeting a reduction of 40% in embodied energy rising to 65% by 2030. We can do this by reducing energy used in construction, reusing materials and designing for disassembly so that the carbon locked in the building can be reused in future.
It is also important to consider the impacts of extraction, pollution, ozone, water use and waste disposal. This can be done through the Building Research Establishment Environmental Assessment System (BREEAM) which rates buildings as ‘Pass’, ‘Good’, ‘Very Good’, ‘Excellent’ and ‘Outstanding’. There is also a Home Quality Mark for new homes and a Civil Engineering Environmental Quality Assessment for infrastructure and public realm schemes.
Parts of the country are in areas of ‘water stress’ and it is important that buildings minimise their water use. Measures include action to reduce leaks, water metering, efficient appliances and taps, rainwater harvesting and grey water recycling systems.
A good target is 105 litres per person, per day, plus 5 litres for external use. However, some schemes might aim for ‘Water Neutrality’, which is defined by the Environment Agency as: ‘For every new development, total water use across the wider area after the development must be equal to or less than total water use across the wider area before development.’
What You Can Do
Where communities are commissioning or refurbishing buildings or developing new houses, it is important to agree on the environmental specification at the outset. This should include specific targets rather than general aspirations and should be monitored throughout the design and construction process, and post occupancy. Where communities are commenting on development they should ensure that developers do the same. Communities might also want to develop a community energy scheme for their area, looking at opportunities for renewable energy and retrofit. This could develop into a local energy network controlled by local people.
Developers and Designers
Stop making vague statements of your commitment to the highest environmental standards and then trying to retrofit measures into schemes that have already been designed. Set clear environmental targets at the outset and make meeting these a requirement for all members of the design team.
Consider going beyond the Future Homes Standard or bringing forward the target dates in local planning policy. Consider introducing measures on BREEAM performance, embodied energy and water use in local plan policy where legislation allows this.
3C) Lammas Eco- Village, Swansea
The Lammas Ecovillage is a collective of smallholdings and dwellings in North Pembrokeshire. Plots contain a house, greenhouses and farmland, and barns or workshops.
The village was developed in line with the Welsh Government’s innovative ‘One Planet Development’ (OPD) policy and was part- funded by the Department of Energy and Climate Change (DECC), which paid for a Community Hub and learning centre.
The OPD policy makes it possible to build new homes in the open countryside in Wales so long as there is a demonstrable, measurable commitment to sustainable living. Residents must maintain a low carbon footprint and buildings should be carbon neutral in construction and use. The Lammas village accommodates an affordable and sustainable lifestyle, with residents growing food and generating energy onsite. Buildings are constructed of natural materials, and energy is obtained from renewable sources. Residents use hydropower, solar power and wind turbines. Heating is supplied by converting the spare electricity generated onsite into heat, or by burning timber, including waste timber, from woodland management projects. Water comes from a private spring and rainwater harvesting.
The site was carefully selected, with nearby woodland providing foraging opportunities, and creating natural shelter from the wind without overshadowing crop-fields. Biodiversity has been increased on the land with over 10,000 trees, shrubs and plants planted and the creation of 6 ponds. Land-based enterprises include fruit and vegetable production, livestock and bees, woodland crafts, and seed production.
The project was the first ecovillage in the UK to attain planning permission in 2009, with initial proposals for nine smallholdings. Under the conditions of ‘One Planet Development’, residents submit annual progress reports to the Council, monitoring traffic generation, land-based productivity and ecological footprint.
While the policy has come under certain local scrutiny, and some OPD schemes have been unsuccessful, the principle of encouraging continual site performance monitoring through post-occupancy evaluation enables continual learning, and Lammas is a successful example of this.
Photography: ©Lammas.org.uk, ©Grand Designs, ©Mikhail Riches