Sustainable Design, embodied energy and construction
Code
For the most efficient use of resources, such as building materials, energy and water over the lifetime of a building the following steps must be taken (listed with highest priorities first):
Repair, re-purpose and re-use existing buildings, structures, boundary features and infrastructure (such as roadways, drainage, earthworks) in order to capture their embodied carbon.Re-use, strengthen or introduce landscape features that will improve the building’s energy efficiency by changing its microclimate. Examples include tree lines or hedgerows that provide shelter from the prevailing wind, planting that will provide shade and reduce overheating, building into the hillside for greater thermal efficiency, or green roofs that are less heat absorbent than roofs faced with minerals or metal.
Use locally-sourced and non-toxic building materials that have low embodied carbon and can be recycled or or-purposed at the end of the building’s life. With this in mind the whole life costs of obtaining, maintaining, replacing and disposing of materials must be considered.
A ‘whole house’ approach to energy efficiency that considers levels of insulation, the orientation of rooms and openings, airtightness, natural ventilation and achieving comfortable conditions in periods of warmer and drier weather.
Design in anticipation of future adaptation, alteration or disassembly considering how current and future occupiers’ needs may change, for example due to old age, disability or a growing family.
Local Plan Policy 20, renewable and low carbon energy, supports development that increases the proportion of energy generated by renewable and low carbon sources and encourages energy provision from local scale generation. For conversions of existing buildings consideration will be given to the character and historic significance of the building.
Conversions should include on-site renewable energy generation that can easily be altered or upgraded. Renewable energy generation options (most favoured to least favoured) include:
Photovoltaic panels – for both electricity generation and water heating
Air source heat pumps
Ground source heat pumps
Micro-hydro power (where possible)
Biomass
To minimise the carbon generated through construction and development, new development should:
Re-use and adapt existing building materials, especially materials that contribute to local distinctiveness such as locally quarried stone and slate.
Use locally sourced and/or low carbon building materials such as:
Sustainably sourced timber
Locally quarried building stone and aggregate
Locally quarried slate
Natural lime for mortars, renders and limewashes
Minimise the use of building materials that require large amounts of energy and resources to produce and/or cannot be readily recycled:
Concrete and cement, including in render and other finishes.
uPVC, aluminium and steel-framed glazing, windows and doors (aluminium is preferred to uPVC).
Avoid synthetic materials such as artificial roof tiles or cladding.
Anticipate the need for external hard and soft landscaping, roofing, rainwater goods etc. to be resilient for more extreme weather events (rainfall, winds) and a warmer climate with warmer and drier spells.
To promote a circular economy and reduce the emissions associated with the end-of-life use stage, building methods and materials that can be dissembled and recycled should be prioritised. The Whole Life Carbon Assessment for the Built Environment provides additional guidance about whole life carbon assessments.
A Life Cycle Assessment (LCA) should be completed at the design stage to identify improvements to the design with regard to embodied energy and carbon footprint of the proposal.
Energy Efficiency
Glazing designs should incorporate measures to prevent overheating. These measures should also reduce the glare and light pollution that such openings may emit.
Tree planting and other soft landscaping features should be used to provide shading and wind buffering to avoid excess cooling/heating of building interiors.
A Life Cycle Assessment (LCA) should be completed at the design stage to identify improvements to the design with regard to embodied energy and carbon footprint of the proposal.
Building design should follow the LETI (London Energy Transformation Initiative) Climate Emergency Design Guide , with specific reference to the small-scale residential architype guidance. The following targets should be set – alongside other guidance on heating and hot water and demand response:
Energy Use Intensity target of 35 kWh/m2/year excluding renewable energy contribution
Renewable Energy Generation and Low Carbon Technologies
Renewable energy measures that are sensitive to the local area and character of buildings should be incorporated into all types of development. For conversions of existing buildings consideration will be given to the character and historic significance of the building.
Solar
Solar photovoltaics (PV) produce electricity from the light of the sun. Solar PV should be used across the National Park, but care must be taken to select solar PV with the least visual impact.
Solar thermal panels collect heat from the sun to heat hot water. They work best alongside existing water heating systems which can help top up the heating system in winter months when solar energy is less abundant. Solar thermal should be used across the National Park, but care must be taken to select solar thermal with the least visual impact.
To minimise the impact of a solar systems on the character of settlements and buildings these factors should be considered:
Colour – the colour and finish of solar panels should be chosen to blend with the roof it is mounted on and any surrounding buildings.
Framing – panels without frames, or black framed panels, should be used where framed panels would detract from the building.
Symmetry – panels should be laid in a symmetrical pattern. Aerials and flues should be moved to facilitate a symmetrical solar installation.
Size – panels should cover the entire roof of a building. If the roof is not symmetrical, don’t visually overload the roof – if you can’t achieve a clean edge install fewer panels.
In-roof or on roof – where possible in-roof panels should be installed. Where on-roof panels are used, the distance between the panel mounting system and the roof should be minimised.
Visibility – the location of a solar system can impact on the roofscape of settlements. Panels should not be installed on the main elevation of a building. The main elevation is the face or faces of a building seen from the direction from which it is most commonly viewed.
Biomass is mainly the use of logs, wood chips, wood waste or pellets to create electricity and heat. Biomass should be considered as a source of renewable energy generation when designing new developments. Small-scale domestic uses are likely to constitute permitted development, although permission may be required for larger schemes in community or commercial buildings. Biomass fuel from a sustainable local source will be encouraged.
Heat Pumps
All conversions should include ground or air source heat pumps. Heat pumps are well suited to new build developments and can also be suitable in traditional buildings.
Ground source heat pumps use pipes that are buried underground to extract heat from the ground.
Air source heat pumps transfer heat from the outside air into a building to provide electric heating to generate hot water and heating. An air source pump unit will need to be fitted to a wall or placed on the ground, with plenty of airflow around it.
Central placement from the top, bottom, right and left hand edges of the roof makes this thermal water PV panel look less like clutter and means the slate covering still dominates.
Roof-mounted panels such as these involve the least disturbance to the fabric of the roof and so are preferred for traditional buildings with slate roof coverings. Image credit: CAfS
New homes with symmetrically placed in-roof solar panels.
