The existing housing stock contributes a significant amount to carbon emissions across the country. All homes will need to decarbonise over the next decade. The Council has agreed to set a target for the Council's housing stock to reach net zero emissions by 2050, and for all homes within the Council's housing stock to achieve an Energy Performance Certificate (EPC) C by 2030.
Extensions and refurbishment works offer opportunities for improving the environmental performance of a home. Improving the energy efficiency of your home can save you money and make your home more comfortable. Undertaking works as part of an extension can be a cost effective way of improving your home. The guidance in this chapter should be considered as part of all householder applications.
The energy hierarchy should be followed, which is:
reduce the need for energy at home,
install different types of energy efficiency measures and
install renewable energy measures.
Following sustainable design principles such as orientation to maximise natural daylight, avoiding overheating and natural ventilation will help you reduce energy demand.
Any new appliances should be energy efficient.
When designing extensions, there is an opportunity to orient them to the south to maximise natural daylight and sunlight into your house and take advantage of passive solar gain (absorbing the sun's heat energy to warm internal spaces). However, it is important to consider that rooms facing south should be designed with shaded glazing to exclude high-angle summer sun and good ventilation to help with natural cooling during high temperatures.
Where airtightness is improved through replacement of windows or doors, mechanical ventilation with heat recovery should be installed to reduce the risk of condensation building up which can lead to damp, mould and poor indoor air quality.
Building fabric and materials
Existing buildings can be retrofitted to improve thermal performance. Care should be taken to select the right materials to ensure moisture can pass freely through the building element and not get trapped. More information on this can be found in the Forest of Dean, Cotswold and West Oxfordshire District Councils' Net Zero Carbon Toolkit. By selecting insulation with some thermal mass (e.g. wood fibre board) temperature variations throughout the day can be moderated.
Work from home
In a post Covid-19 society, more people will be working from home and this trend is likely to continue as our digital infrastructure continues to develop. If your home does not currently have a room or space for working from home consider incorporating a work from home space into your extension.
Renewable and low carbon energy
All existing buildings should replace fossil fuel based systems with low carbon heat alternatives as a matter of priority.
Air Source Heat Pumps use heat from the air outside (even when its freezing) to heat your home via radiators, underfloor heating or to heat water in a storage tank for use in the kitchen or bathroom. Air Source Heat Pumps can be retrofitted into existing buildings if there is a suitable location for the outdoor unit. Heat pumps are suited to underfloor heating and larger radiators. However, existing radiators may be sufficient if the building is moderately energy efficient. If the existing building has poor energy efficiency, improvements should also be made to the building fabric, as part of a considered whole house retrofit plan. If a gas boiler is being replaced during an extension or refurbishment replace with an Air Source Heat Pump.
Solar photovoltaic (PV) systems turn sunlight into electricity through the 'solar cells' they contain - this electricity can be used to power home appliances. To install solar PV, your roof should face south and have between 2-5 sq.m of available space free of shading.
Owners of listed buildings and/or sites within conservation areas should seek the advice of the Council's Conservation Officer.
Consider installing a charging point for electric vehicles to help support sustainable movement.
There are financial incentives available for installation of renewable energy technologies. These change over time and so are not listed in this SPD. Up to date information can be found on the Energy Saving Trust website.
Water efficiency measures
To reduce water demand, water use should first be minimised through efficient fittings. Rainwater harvesting systems and water reuse systems further reduce water usage.
There are simple measures that can easily be included in new bathrooms and kitchens, but that can also be added to existing. Anglian Water Services include water saving information on their website.
Consider installing a rainwater harvesting system, which collects, filters and stores rainwater within an underground tank, or a greywater recycling system, which collects, processes and stores greywater (wastewater from showers, baths and wash-hand basins) for subsequent re-use as non-potable water, ie for toilet-flushing, clothes-washing machines, and irrigation. If you do not have a water butt in the garden, consider investing in one as a way of collecting rainwater which can be used for watering the garden.
If you are having trouble using the system, please try our help guide.