Understanding Retrofit

We are facing two crises in the UK – the urgent need to reduce our carbon emissions and the need to respond to rapidly increasing energy prices. There is an increasing need to take action to reduce energy use from our buildings to not only save money but to take action in the fight against climate change. This is where “Retrofit” comes in.

Retrofit refers to improvements on an existing building to improve its energy efficiency. By retrofitting our homes and other buildings (inc. key community spaces), we are making them easier to heat, able to retain that heat for longer, and replacing fossil fuels with low carbon and renewable energy options.

What are the benefits of retrofit?

As well as reducing energy costs and our carbon footprint, retrofitting has a number of other co-benefits:

  • Addresses fuel poverty
  • Creates jobs through building trades
  • Reduces health costs to the NHS through improving cold homes and community spaces (which exacerbate health issues)
  • Reduced excess winter deaths associated with cold homes and community spaces
  • Better quality working and community spaces
  • Addresses overheating in the summer

Retrofit principles – Energy Hierarchy

Before embarking on your retrofitting journey, it’s important to understand a few key principles.

To reduce our energy use and decarbonise our homes in the most cost-efficient way, we need to consider the “energy hierarchy”.

Basically, cost effectiveness (bang for your buck or £ per carbon saving) decreases as you go up the pyramid. There is no point spending a great deal of money on a heat pump for your home/building and generating low carbon heat if your building is just going to lose a lot of that heat through poorly insulated walls and draughty windows. Thus, the standard advice is usually to:

  1. Start with reducing energy demand. You can do this through behavioural change – is there anything that you as a householder (or as a place of worship) can do to reduce energy use?
  2. Next is to look at increasing energy efficiency – insulation, windows and doors, better appliances within the building etc.
  3. Then look at generating renewable or low carbon energy if appropriate and possible such as maybe replacing your gas heating system with an air source heat pump or ground source heat pump.

If you invest money into installing a heat pump or solar panels without considering the first two steps then you may be spending more money in the long run than is needed. And the carbon savings won’t be as high.

Whole-building approach

all hallows by the tower church in london
Photo by Olga Lioncat on Pexels.com

It’s important to understand the building or house before you start decision-making. This approach sees the home or building as a whole system and not a series of disconnected parts.

This approach is widely regarded as central to the retrofitting world, and helps decides which measures to install and in which order. It also helps to identify potential problems. It’s important to consider even if you are only intending to install one measure because it can avoid unintended consequences.

Planning measures in isolation rather than as part of a joined-up process risks incurring unforeseen and possibly undesirable outcomes.

Useful video about whole house approach:

Fabric first approach

Dennis Schroeder / NREL

This is a key approach in the retrofit world where improvements to the energy efficiency of the buildings’ external shell is prioritised before building services and renewables are considered, to ensure energy demand is as low as possible. This approach consists of:

  1. An even, all round insulation: to maintain a consistent internal surface temperature
  2. An airtight building envelope: with a continuous, unbroken air barrier
  3. Vapour permeable construction: to promote the safe passage of moisture

Maintenance first

Community Environmental Center

Good maintenance of homes/buildings is the main way to increase both comfort and efficiency of the building, as it allows the building to work as effectively as possible. For instance, rotten windows will be letting draughts in and heat out, whilst cracks in the guttering or render may contribute to damp, which in turn makes a home harder to heat to a comfortable temperature. Maintenance makes your home/building ‘retrofit ready’ and should be done before undertaking larger measures.

Understand your building

It’s important to understand how your building was designed, and the difference between traditional and modern buildings. Traditional homes/buildings would have been built using natural materials and designed in a certain way to let oxygen in (as they were reliant on fires for cooking), and bad air out because or worse air quality in the building. The ventilation that was built into the property was done so for a reason, so any changes need to manage this correctly.