Whole house approach
Retrofit assessments involve assessing the whole of the building including occupancy, ventilation and condition. This provides
- A true energy baseline for each property.
- Identify any issues or constraints
- Identify any specific measures for improvements.
Why it matters?
Each house is assessed individually in order to understand
- Occupancy patterns
- The condition of the property
- The construction and the presence of any extensions
- Site specific issues such as shading from a tree, access issues
The whole house assessment will ensure the correct energy efficiency measures are applied without causing unintended consequences. Such as condensation or mould or overheating.
If the project needs to comply with PAS2035 a whole dwelling assessment is a requirement and a Retrofit Assessor is appointed.
The whole house assessment includes
Property condition:
This is a basic assessment of the structural condition. Retrofit assessors are not structural building surveyors so will report only what is seen, such as cracks, loose cladding are two examples. This would trigger a further report by a professional building surveyor. The structure of the property needs to be intact before any works can be agreed.
Damp or condensation – This would indicate something is amiss with the property. Rising damp means water is seeping into the building envelope and condensation could mean a number of things from poor ventilation, insulation not continuous, thermal bridging but to name a few examples.
Windows – The assessment reports on the age and condition of the windows. If trickle vents are present and are able to open and close.
External brickwork or any cladding – The brick face and mortar joints are intact, cladding methods are intact. These factors are important as keep the property dry from wind driven rain.
Roof – The assessment reports on both the external roof tiles and internal loft space.
Occupancy Assessment:
This takes into account the number of people living at the property and the number of bedrooms to understand the occupancy.
The number of people will impact how much moisture is generated from showers/baths, boiling the kettle for example. So if the property has two bedrooms and five people live there for example then it is more at risk of moisture build up internally and mould or condensation forming.
The occupants are the best people to tell the retrofit assessor about the performance of the property. How it feels in the summer and winter months. Where mould accumulates, where it is draughty are useful examples.
The occupants also tell you about their heating patterns and how often they use central heating programmers as an example.
This is all useful information to help build a picture of how the property is used and which energy efficiency measures would be best suited.
Ventilation assessment:
As buildings become more airtight, controlled ventilation methods are important to ensure the air is exchanged and warm moist air is expelled. A ventilation assessment is carried out to see if the existing systems are adequate. The retrofit assessment again provides a baseline from which improvements can be modelled.
Measured floorplans and photographic evidence. The floor plans show the room layout. It will identify location of electric or gas meters, radiators, windows, light fittings, loft hatches and any other points of interest. Photographic evidence is required so the retrofit co-ordinator and designers can see what the retrofit assessor has reported.
What happens next?
Once the data is collected by the Retrofit Assessor, the reports and photo packs are shared with the Retrofit Co-ordinator. The building will be modelled in an energy calculation software package.
The output provides a baseline for energy consumption. From this different energy efficient measures can be modelled and how they can improve the energy efficiency and carbon emissions. It will also deliver improvements that do not inadvertently have negative consequences. This is known as the Improvement Option Evaluation in PAS2035 and is a requirement for compliance.
The different packages of retrofit measures will show the benefits of each option in terms of a payback period and carbon cost effectiveness.
