What is a retrofit assessor and how could they help you improve your home? - Grand Designs Magazine

What is a retrofit assessor and how could they help you improve your home?

A retrofit assessor could be just the person you need to recommend the right green upgrades for your home

By Mary Richards |

The role of retrofit assessor is a relatively new one. It is one of several job roles devised by the government as part of its programme to help the country reach its Net Zero goals. This video shows a day in the life of a retrofit assessor.


Other job roles you might encounter on your retrofit journey are retrofit coordinator, retrofit advisor, and retrofit evaluator. These jobs were identified as a result of recommendations in the government’s 2016 Each Home Counts report, which put forward ways to improve and better regulate the home retrofitting industry. When we mention ‘retrofitting’ in this context, we are talking about the installation of modern energy-efficiency measures, such as, say, insulation and low-carbon heating like heat pumps, into existing housing stock.

PAS 2035

As well as designing these important new green jobs, the government has helped set out standards for retrofitting work. The standards governing retrofitting in private homes are called PAS 2035 Specification for the energy retrofit of domestic buildings. These standards were felt necessary because this is a relatively new industry, and installing things like insulation into old homes can be a tricky, complicated business. It’s not as simple as slapping on some insulation and hoping for the best; work needs to take account of issues such as moisture control in the property and ventilation. Without proper training and due care, contractors may use inappropriate materials and techniques, which just create long-term problems in the fabric of the building such as mould or rot.

Whole-house approach

We now understand that the best way to tackle retrofitting energy-efficiency measures is using a whole-house and fabric-first approach. The former means taking a holistic view of the building, the work you want to do, and how it will be ventilated, in preference to the piecemeal application of individual energy-saving measures. The latter involves making sure the structure of the building is sound before starting work and implementing basic energy-saving good practices at the start, such as changing to low-energy bulbs, installing a smart meter, etc.

Retrofit assessment

A retrofit assessor is someone who can undertake an assessment of your home and suggest the best way forward. If you book one to do a retrofit assessment of your house, this will cost between £100 and £300 depending on location and the size/nature of your house. They will produce a report comprising:

  • an energy report, setting out the current energy use of the property,
  • a condition survey, that looks at any issues with the fabric of the building that might,
  • an occupancy assessment that looks at how much and when you use energy in your house.

Make sure you book a qualified assessor. You can find some on the TrustMark website. Some private training companies such as Elmhurst Energy, which are in the business of training new retrofit professionals, also have databases of assessors. As yet, there are still limited numbers of assessors. But their ranks are growing.

The assessment will take up to a couple of hours depending on the size of your house. Here’s a video showing people having an assessment done at their house.


The report you get will include a unique mixture of recommendations specific to your home. These might include: repairs to the fabric of the building, the installation of various types of insulation, meters and monitoring, and the installation of other energy-efficiency measures. Assessors are trained to take into account how moisture will move through the refurbished home, and how it should be ventilated.

Getting the work done

If you decide to take the recommendations further and get the work done, you should find installers who will work to the PAS 2035 standard. You will probably need to employ a retrofit coordinator to project manage the works and ensure they come up to standard.