Energy-efficient housing refurbishment

Context

The need for energy-efficient refurbishment
Housing is responsible for 27% of the UK's carbon emissions

Design Guidance

	Start here: Developing a refurbishment strategy Developing a design and implementation strategy is critical to the success of an energy-efficient refurbishment. The strategy will involve setting priorities and identifying methodologies that are appropriate to the existing building as well as understanding the potential of fabric changes and equipment application.
	Solid wall insulation: Insulated render Through careful detailing and managing the appearance of the building, insulated render can offer a cost-effective and efficient method of upgrading an external wall.
	Solid wall insulation: Timber, slate & tile cladding Cladding offers the best performance characteristics by separating the thermal insulation from the weatherproof layers. It also offers the designer a wide flexibility in the specification of cladding material and façade design.
	Solid wall insulation: Rainscreens As its technology and benefits have become more understood, rainscreen cladding has developed as a mature market over the last 25 years. Its success has been particularly realised in its application to high-rise buildings.
	Solid wall insulation: Internal lining Though internally applied insulation can often be problematic in its application, it has the potential to significantly enhance the thermal performance of external walls.
	Ventilated pitched roof insulation The 'ventilated' type of piched roof is the traditional form of roofing in the UK. Where this type of construction is to be maintained as part of the refurbishment, there are methods of insulation that can be employed to restrict heat loss.
	Unventilated pitched roof insulation Replacing the existing roof covering provides the best opportunity to upgrade the insulation. Adding insulation can be done in a number of ways to make best use of recent devlopements in the technology of breathable sarking membranes.
	Loft insulation If the roof space is not to be developed as habitable space, providing new or upgrading the existing insulation provides for the easiest and most cost-effective way of improving the overall thermal performance of the house.
	Timber flat roof insulation 'Cold' construction timber flat roofs are a common feature of many existing house extensions. If the roof is to be maintained as part of the refurbishment, the roof insulation and covering are likely to need upgrading.
	Concrete flat roof insulation 'Cold' construction concrete flat roofs are more durable than timber flat roofs. But a concrete roof usually shares the same problems as its timber equivalent - poor thermal performance and high condensation risk, which will have to be addressed as part of the refurbishment.
	Ground floor insulation The addition of insulation to an existing ground floor concrete slab is contentious, but can bring benefits if added when a new slab is installed. Suspended timber flooring will always benefit from the addtion of insulation.
	Windows Old windows are notorious for their poor performance, but their replacement needs a careful understanding of the dynamics of heat loss together with an awareness of the range of material technologies that can be applied.
	Airtightness The implementation of a strategy to enforce air-tightness using materials, careful detailing and construction, is key to realising maximum thermal performance.
	Whole house ventilation A well-insulated, airtight house performs at its best when the ventilation to its spaces is controlled to minimise heat loss.
	Space & hot water heating: Gas fuelled Currently, for the vast majority of refurbishment projects, gas fuelled space and water heating will be the likely choice. The designer will need to choose between a range of options.
	Space & hot water heating: Wood fuelled Wood is rapidly entering main-stream as a boiler fuel - though the UK has some catching up to do with the continent, especially where wood has been a traditional fuel. The specification of a wood-fuel boiler will need careful consideration to ensure correct sizing as well as the assurance of fuel delivery.
	Heat emitters: Radiators and underfloor heating Though it will be debatable whether it is actually necessary to provide heating emitters for a house that has been insulated to Passivhaus standards, the majority of refurbishments will probably need radiators or underfloor heating to some degree.
	Solar thermal systems Solar hot water heating is probably the most efficient, cost effective and simplest of all 'renewable' technologies to install. Though reccommended as part of the refurbishment, it can also be installed at a later date more easily if the necessary pipework and water storage is installed as part of the current works.
	Heat pumps Heat pumps in some circumstances can be used on their own, but they will usually be installed in conjunction with a boiler heating system. Use of heat pumps should be considered judiciously – any benefit is likely to be achieved only within certain conditions.
	Electrical power: Micro-generation The choice of a reliable domestic-scale system is practically limited to photovoltaic (PV) panels and wind power where available. Though with the prospect of workable micro CHP (combined heating and power) technologies in the offing, the range of opportunities for micro generation is set to expand.

Case studies

1930s terrace house
An exemplar refurbishment of a inter-war terrace house for Hyde Housing Association