Retrofit For The Future: Reducing Energy Use In Existing Homes

Retrofit is the introduction of new materials, products and technologies into an existing building to reduce the energy needed to occupy that building.

Retrofit is not the same as renovation or refurbishment, which often make good, repair or aesthetically enhance a building without aiming to reduce its energy use.

The Retrofit for the Future programme has been exploring how existing homes can be improved to use less energy, cut carbon emissions and save costs. The £17m programme, funded by the Technology Strategy Board (TSB), has helped businesses discover new opportunities in the growing retrofit market.

In 2009, funding of up to £20,000 was awarded to 194 project teams to develop a retrofit strategy. Up to £150,000 was then awarded to 86 of those teams to find out how their strategy would work in real homes: ambitious targets were set to reduce energy use and carbon emissions.

The Technology Strategy Board worked with the Energy Saving Trust to develop tools to measure the actual performance of the retrofit homes so they could be compared to each other and against performance targets. The tools included:

• data on energy use

• data on water use

• environmental conditions

• spot test reports from thermography (heat losses)

• airtightness (air leakage) tests

• independent on-site technical reviews of the completed retrofit homes

• interviews with residents

• project team diaries

• final project reports

Six retrofit themes provide a framework for considering what was done well and what could be improved:

• Retrofit planning

• Building fabric

• Indoor air quality

• Services

• Working on site

• Engaging residents

A successful retrofit will encompass all these factors in a ‘whole-house’ approach. When attention to detail and clear communications are added to the mix, the results are much more likely to lead to better energy savings.

The building fabric constitutes the walls, roof, floors, windows and doors. The fabric is a major area of heat loss which can be reduced by adding internal or external wall insulation, loft and floor insulation, and improvements such as new glazing.

An additional way to reduce heat loss is to improve airtightness. This is to minimise unwanted air flow in or out of the house. However, people still need fresh air to be brought in as ventilation. The balance between airtightness andventilation can be addressed in different ways. The majority of the Retrofit for the Future homes chose MVHR (mechanical ventilation heat recovery) systems, whereby heat is recovered from warm air taken from kitchens and bathrooms before it is expelled while fresh air comes from a separate point.

Services (such as heating and hot water systems, lighting, renewable energy, controls) have to work with the insulation, airtightness and ventilation of a home to provide comfort and convenience. The installation of different retrofit elements can involve complex construction works and multiple suppliers, so careful planning of work both on and off the site is important. How all these factors are brought together in one house can have a large impact on the people living there and the way they use their new energy systems. The residents’ input can be invaluable and softer skills are necessary to keep them engaged through the retrofit process.

Retrofit for the Future shows that a whole-house retrofit can provide huge financial, comfort, carbon and social benefits. A good retrofit also helps prevent health risks from damp and mould, reduces the risk of fuel poverty and generates local employment. The reductions in energy use and carbon emissions can be as much as 80%.

Next issue, we’ll look at a case study of retrofit in action at a North Belfast mid-terrace solid wall house built in 1896.

For further information about the Technology Strategy Board, visit www.innovateuk.org