Retrofit is the process of altering existing buildings so that their energy efficiency can be improved.
Done correctly, such changes should also provide a more comfortable and healthier home as well as lower fuel bills. To get the most from the improvements you are making it is essential to assess the changes in combination so that the impact of each on the others is understood. This holistic approach ensures all relevant factors are properly considered when planning improvement works.
There are two primary approaches generally considered for retrofit projects.
This is a straightforward approach aimed at upgrading the fabric (e.g. roofs, walls, floors) of the building first, before addressing more complex things such as heating, hot water, or lighting systems. Fabric first generally means improving insulation around the building and reducing heat loss through draughts such as around windows and doors.
However, careful consideration needs to be given to maintaining the appropriate amount of ventilation to avoid damp or mould and to maintain a healthy environment. Simply blocking all ventilation pathways is not the right approach. Professional advice should be sought on the suitability of measures.
This is where an assessment is carried out by a qualified retrofit professional. They will consider the whole house, the fabric (e.g. roofs, walls, floors), the systems present (heating, hot water and lighting) and the energy used. Because everyone’s home is different, the assessment also takes into account how the occupants actually use their home.
A plan is prepared which is generally divided into separate phases so work can be carried out progressively and as efficiently as possible. For each phase, the plan includes estimated costs of work that can be undertaken, estimates of the resultant energy savings and the amount of carbon reduction that can be made. The homeowner can then decide which measures should be undertaken and when.
It is important for the plan to be developed and managed by a qualified and accredited retrofit professional in order to ensure the right balance. Improving building fabric and increasing air tightness to minimise heat losses is generally sensible because insulation has a relatively low cost and a long lifespan. For most people this will be a one-off cost. Heating and hot water systems on the other hand have a shorter lifespan and will probably need to be replaced every 10-15 years. However, it is essential to also consider whether the measures are actually appropriate for the building and the way the occupants use it.