What are concerns and actions?

The retrofit of buildings raises many different kinds of issues. These include areas that need to be addressed in order for the measure to be successful in terms of saving energy but also cover the need to minimise unintended consequences. Concerns, in the context of the Guidance Wheel, refer to such issues. Concerns can refer to:

If a Concern is raised, there may be ways in which the concern can be assessed or managed – and in the Knowledge Centre these are referred to as Actions. The suggested actions have been set out to take place before, during and after a measure has been implemented.


Technical concerns arise whenever the normal functioning of a building is altered by a retrofit measure. For instance, the addition of insulation to a building element changes the temperature gradient through that floor, wall or roof. In some cases this can lead to the build-up of condensation – either on interior surfaces or within the building structure (interstitial condensation).

Many retrofit strategies will reduce uncontrolled air flow through buildings, contributing to moisture build-up. The provision of adequate ventilation is essential to the health of buildings and of their occupants.

Other technical concerns refer to the need for care in design and detailing, building warrants and other permissions, complexity (either of design, installation or operation), the need for maintenance and aftercare, including monitoring and feedback, user aspects such as handover to users, personal preference and finding the right opportunity for the retrofit.

Actions for the technical concerns vary according to the concern itself. They may include:

  • investigations of the quality of the existing building and fabric, and any repairs needed;
  • choosing the correct standards for testing the specification of either materials or equipment;
  • monitoring the fabric of the building at high risk areas;
  • engaging users to understand their needs, providing them with clear information through the process and seeking feedback after implementation.


Heritage concerns arise where retrofit measures have the potential to cause undue damage to the character of a traditional building. This character may be a particular feature or detail, or may be the overall appearance and form. The judgment of what constitutes character is not always easy, and where there is any doubt it is best to consult a conservation officer, or other expert.

One example of a heritage concern may be the addition of solid wall insulation. The addition of insulation to traditional buildings will disturb, damage or cover up historic fabric, in some cases radically altering the building’s appearance. Solid wall insulation, by definition, is placed on the inside or outside of a solid wall so it is necessary to assess the value of existing appearance, including details such as window cills, eaves details, cornices, and skirtings, depending on whether the insulation is applied externally or internally.

Actions relating to heritage concerns include the investigation of the building fabric significance, consultation with the local planning authority and conservation officer and maintaining the communication with these authorities during the implementation process.


Energy concerns refer to the uncertainty of the expected savings being delivered in practice. There are several reasons why the energy saving expected from a retrofit measure may not be achieved. Measures to reduce the demand for space heating will make a property easier to heat but if it was under-heated beforehand the occupants may prefer a higher average temperature afterwards – this is known as “comfort take-back” and is one example of the rebound effect in energy savings.

Savings from insulation measures can also be below modelled savings if the building fabric was performing better beforehand than had been assumed. Occupants need to understand how the retrofit process will have changed the way that the building performs, and to know how to control it effectively. The choice of default settings for heating and ventilation would need to be fine-tuned with the occupants to align with their expectations and deliver the minimum requirements for building and occupant health. A process that includes quality of specification and detailing, product choices, installation and commissioning should help to reduce the performance gap in operation.

Actions relating to energy concerns include understanding the existing fabric and occupancy patterns of the building in use and defining a quality process of checks during and after implementation to ascertain what was specified has been installed correctly.