Q1: What will complying with the new Part L guidance for housing entail?
The new Part L introduces a new criteria for compliance, which is a Target Fabric Energy Efficiency (TFEE) value. The concept of FEE has been around for a while and was calculated for the energy credits under the Code for Sustainable Homes. It is calculated through SAP 2009, but there is now a mandatory requirement to comply with a target value.
With the introduction of this fabric performance standard in addition to the TER (Target CO2 Emission Rate) values, a fabric first approach will need to be taken, but renewables or MVHR are likely to form part of most strategies for compliance.
Q2: What specific considerations will need to be made in order to meet the TFEE?
The industry has been preparing to offer solutions for improved U-values across construction types in anticipation of the Fabric Energy Efficiency Standard (FEES) standard becoming mandatory from 2016. The focus in the new Part L will however be on providing adequate information to support heat loss calculations through thermal bridging.
Some construction system manufacturers offer standard details with corresponding psi-values and software is available for designers and consultants to calculate these for bespoke details. More guidance and information on this is due from DECC.
Q3: Have there been any changes to the minimum requirement for system efficiencies?