Technical Booklet F1 Conservation of Fuel and Power in Dwellings·Page 22·2.10
Conservatories and highly glazed spaces with thermal separation
A conservatory with thermal separation may be excluded from TER and DER calculations and air pressure testing, but if it is heated or cooled by a fixed building service, it must meet specified requirements.
Where a conservatory, constructed as part of a new dwelling, has thermal separation from the dwelling, the TER and DER for the dwelling may be calculated as if the conservatory is not present and the air pressure test should not include this space. However, irrespective of the conservatory being ignored for the purposes of calculating the TER and DER, where the conservatory is heated or cooled by a fixed building service either taken from the main system or provided solely in the conservatory, it should have –
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