In the current version of Approved Document L1B (England), a conservatory with a floor area less than 30m2 is exempt from the energy efficiency requirements. This is provided there is an appropriate thermal separation between the conservatory and dwelling and the heating system of the dwelling is not extended into the conservatory. Where these conditions cannot be met, then the glazed elements should meet the requirements for replacement windows and doors (referred to as controlled fittings).
There are no changes to these requirements in the 2021 editions of Approved Document L Volumes 1 and 2, which will be in force from 15th June 2022. For more information on the requirements for conservatories in Approved Document L, please check out the relevant section of the Part L hub by clicking here.