The AECB Retrofit Standard
The AECB building standards offer the construction industry new routes to achieving high building standards. Below, Dr Sarah Price gives an overview of the recently launched AECB Retrofit Standard.
Why is there a need for a new Retrofit Standard?
The Passivhaus standard is the ultimate goal for newbuilds, and this is something the AECB completely recognises, seeing its own new build standard as a steppingstone to Passivhaus.
However, when it comes to retrofitting, there are very few standards available, and while the Passivhaus retrofit standard, EnerPHit, is a brilliant aspiration for retrofitters, it can often be unattainable and may be too stringent for most homes in the UK. The AECB Retrofit Standard offers a pragmatic approach to the energy demand targets, which are still potentially lower than current UK new building regulations.
The main difference that sets the AECB standard apart is that it recognises that every home is unique and focuses on managing retrofit risks to avoid unintended consequences. The self-certification process offered by the AECB Retrofit Standard also helps to keeps costs down.
Energy and Comfort Requirements
The AECB building standard has a retrofit target of 50 kWh/m2 per annum, but an exception may be applied for up to 100 kWh/m2 per annum. It has an airtightness requirement of 2 ach @50 Pa.
By using the Passivhaus Planning Package (PHPP) software and modelling as a design tool the AECB Retrofit standard ensures good thermal and comfort performance, avoiding the ‘performance gap’ of so many retrofit projects.
Managing retrofit risks is key to a good retrofit. The consequences of a bad retrofit can be far worse than doing nothing at all. The AECB retrofit standard has the advantage of addressing the myriad of other issues surrounding retrofit, drawing on all the retrofit knowledge and expertise set out in its CarbonLite Retrofit course. The AECB Retrofit Standard also includes management of risks around moisture, flood, radon, and fire, as well as requiring an excellent retrofit survey that ensures that the building is fit for retrofit in the first place.
Decarbonising Our Buildings
We know that not all buildings are going to meet the EnerPHit standard and that we need a moderate approach to retrofit with an average of around 50% carbon reduction by energy-efficient fabric measures, with some buildings achieving more and some less.
The AECB Retrofit Standard will help projects address retrofit risks and create warm, comfortable, and safe buildings for the long term. This will support the decarbonisation of the grid and reduce peak heating load as we turn to electrical heating in our buildings.
Written by Dr Sarah Price