AECB lifetime carbon modelling suggests that either of our two retrofit standards should deliver dramatically lower lifetime carbon emissions for homes - compared to not retrofitting. Over time we imagine two waves of retrofit happening, with some early Level 1 projects moving to Level 2, depending on future policy and financial developments.
AECB Retrofit Standard Summary and Webinars
Reducing the energy used to heat and power existing buildings, whilst making homes healthier and more climate-change resilient is a critical part of the UK’s necessary transformation towards a more responsible, ecologically, and socially sustainable society.
Our two Retrofit Standards – Level 1 & 2 - recognise the practical and financial challenges faced by ‘early adopter’ retrofitters in the absence of a working UK retrofit programme. They offer a pragmatic and flexible approach to retrofitting existing buildings, and the new Approved Certifier scheme streamlines and strengthens the AECB’s approach to Quality Assurance.
The energy and non-energy benefits of a deeper retrofit may justify adopting the Level 2 standard for some projects, whereas the faster and lower capital cost Level 1 may be more appropriate for other projects. Completing a Level 1 retrofit does not lock out later works to take the building to a cost-effective Level 2. The Level 1 retrofit standard might also be called a ‘heat pump retrofit’ standard as it has been designed for a lighter fabric retrofit, effective ventilation and an electric heat pump. The Level 2 retrofit allows retention of the existing heating system if required, and is designed for a deeper fabric retrofit.
Approved Certifier costs
Please contact an Approved AECB Certifier from our approved list to determine the cost of engaging a suitable person for advising and certifying to each standard. This will be a contractual arrangement between you and the Approved Certifier.
AECB certification fee
A modest submission fee is payable by the AECB Certifier to the AECB for certificating each project. This also contributes towards managing the AECB Low Energy Buildings Database on which certified projects are hosted, and carrying out Certifier training, CPD and QA for the scheme. This fee will be included in your Approved Certifier’s quote. For non-domestic buildings the submission fee is based on floor area and complexity of the project. For domestic projects Certifiers will discuss with you alternative submission options, which may affect the AECB submission fee cost.
There are three alternative options used by Approved Certifiers. They are:
1) Dwelling by Dwelling
2) Dwelling Type and Energy Sub-type
Dwelling by Dwelling
Some clients want each dwelling-type to be certified. This approach closely reflects the methodology used for EPCs. This approach is the most labour intensive and results in a certain amount of duplication. As processing takes longer for the certifier and the AECB this certification approach incurs a higher certification fee. There may be good reason why this is the clients’ preferred approach.
Dwelling Type and Energy Sub-type
On the basis that all dwellings have the same orientation and that there are terraces or flats (rather than detached homes), energy sub-types often occur. This happens when you have mid-terrace and end terrace units. From the perspective of energy performance and certification each dwelling-type could have two (or more) energy sub-types due to the exposure/sheltering of mid-terrace and end terrace units. Energy sub-types also occur where changes to orientation or shading. Whilst the certification fee can be a little lower than other options, because this approach is labour intensive the total cost of certification (which includes the certifiers’ time) is higher.
It may depend on what the end user would like to see: for example in a project where the future owner of a mid-terrace unit wanted to see their exact energy performance a separate calculation (with additional fees) was required.
Where a number of different self-contained units are contained within one continuous thermal envelope it is possible to certify a complete building rather than each unit or energy type. Compared to the ‘Dwelling by Dwelling’ and ‘Dwelling Type and Energy Sub-type’ models there are advantages to adopting a ‘Building-by-Building’ strategy, these include: reduced modelling (saved time) and; reduced evidence collation management (saved time). The house numbers for all the units in each building must be included in the project name which is included on the AECB certificate for that building.
Whilst the certification fee can be a little higher the total cost of certification (which includes the certifiers’ time) is significantly reduced. This strategy typically tends to be used by designers and certifiers certifying to the Passivhaus Standard.
Building an extension as part of Level 1 retrofit
If you are also building an extension as part of a Level 1 retrofit your AECB Approved Certifier will advise on an appropriate specification for this part of the project. Typically, this will involve building a new extension to levels of fabric performance expected from the AECB Building Standard, i.e., excellent U-values and airtightness for walls, floors, roofs, and windows.
Building an extension as part of Level 2 retrofit
If you are also building an extension as part of a Level 2 retrofit your AECB Approved Certifier will advise on an appropriate specification for this part of the project – treating the new and retrofitted areas of the building as a single building and to comply with the overall energy performance criteria of the Level 2 Standard. Typically, this will involve building a new extension to levels of fabric performance expected from the AECB Building Standard, i.e., excellent U-values and airtightness for walls, floors, roofs, and windows.
AECB Building Standard Certification
In order to maintain the integrity of the standards and ensure consistency of application, the AECB uses Approved Certifiers to confirm that projects have met the AECB CarbonLite Standards.
All our certifiers are AECB members, approved by us to carry out project certification. Certifiers undertake regular AECB CarbonLite CPD.
- The AECB Standards are based on the Passivhaus methodology, and certifiers use the Passivhaus Planning Package software (PHPP)
- The certifier may choose to appoint a separate PHPP modeller as part of their certification service, or may do this in-house
- Once modelled in PHPP, certifiers use the AECB CarbonLite LEBD Uploader software to collate project data and evidence and automatically upload the certified project to the Low Energy Buildings Database
Our other CarbonLite Standards
AECB PHribbon makes using PHPP quicker, easier and it uses the existing information beyond just energy. It enables you to build the PHPP faster and the CO2 calculations benefit designers, consultants and clients by making it an easier, quicker process.
Learn more about this exclusive AECB software