A ‘whole house’ approach to domestic retrofit

Improving the energy performance of existing homes is a complex process. Unlike new build properties, existing buildings have individual construction types, heating systems, ventilation arrangements and maintenance histories. These factors can affect both the choice and performance of retrofit measures.

A successful project therefore needs to consider the building as a complete system rather than treating measures such as insulation, heating and ventilation as separate interventions.

Founder and chief executive of The Retrofit Academy, David Pierpoint,  highlights this point in episode 4 of Tomorrow’s Energy: “Every home is different from every other home.”

The starting point for a retrofit project should be an assessment of the property and its condition.

This can identify existing issues such as damp, mould, water ingress, poor ventilation or excessive humidity. Addressing these problems before installing energy efficiency measures can help prevent unintended consequences and improve the effectiveness of subsequent work.

For example, installing insulation around an existing water leak could trap moisture and create more significant problems. Identifying and resolving the underlying defect first forms an important part of a ‘whole house’ approach.

The assessment can then be used to determine which measures are appropriate for the particular property and how they should work together.

This may include improvements to the building fabric, such as insulation and windows, alongside ventilation, heating technologies such as heat pumps, and renewable technologies including solar panels.

The objective is not simply to install as many measures as possible, but to establish the combination that delivers the best outcome for the building and its occupants.

The approach also requires appropriately trained professionals.

Retrofit professionals need to understand building performance, diagnose defects and assess how different interventions interact. This requires skills beyond the installation of individual products or technologies.

The Retrofit Academy is focused on developing this professional capability and establishing greater competence across the sector.

In our podcast David says: “Our focus is on quality and scale and competence really. So, we’re all about trying to build the retrofit profession and championing competence.”

The performance of a retrofit project is heavily influenced by the people living in the property. The residents are the key element.

Residents need to understand how new systems operate and how changes to their home may affect heating, ventilation and energy use. Good communication and support can therefore form an important part of the retrofit process.

Occupant behaviour can also influence measured energy savings. In Tomorrow’s Energy, David refers to the “rebound effect,” where residents may increase their heating because their improved home is cheaper to heat. While this can reduce predicted energy savings, it may also result in improved comfort.

A ‘whole house’ retrofit approach provides a framework for delivering improvements that are appropriate to the individual property.

The key considerations are:

• Assess the building before specifying measures.
• Resolve existing defects before retrofit work begins.
• Consider how different technologies and building measures interact.
• Use appropriately trained and competent professionals.
• Keep residents involved and supported throughout the process.
• Consider performance, comfort, health and energy use together.

For homeowners and organisations planning retrofit programmes, the central lesson is to understand the building first and select the technology second.

As David puts it: “Invest in the understanding of that building and its condition” before investing in the equipment.

This approach can help ensure that retrofit delivers not only improved energy performance, but homes that are warmer, healthier and better suited to the people who live in them.