New Approved Document O (Overheating) – Effective 15/06/2022
Approved Document O – New Dwellings only
Title Purpose for which the building is intended to be used Residential (dwellings) Dwellings, which includes both dwellinghouses and flats. Residential (institutional) Home, school or other similar establishment, where people sleep on the premises. The building may be living accommodation for the care or maintenance of any of the following. a. Older and disabled people, due to illness or other physical or mental condition. b. People under the age of 5 years. Residential (other) Residential college, hall of residence and other student accommodation, and living accommodation for children aged 5 years and older.
Requirement Limits on application O1 Overheating mitigation (1) Reasonable provision must be made in respect of a dwelling, institution or any other building containing one or more rooms for residential purposes, other than a room in a hotel (“residences”) to— (a) limit unwanted solar gains in summer; (b) provide an adequate means to remove heat from the indoor environment. (2) In meeting the obligations in paragraph (1)— (a) account must be taken of the safety of any occupant, and their reasonable enjoyment of the residence; and (b) mechanical cooling may only be used where insufficient heat is capable of being removed from the indoor environment without it.
Dynamic thermal modelling A method of building modelling that predicts the internal conditions and energy demands of a building at short time intervals using weather data and building characteristics.
Summary
This paper is a brief summary of the approved documents, you should read them carefully.
For replacements you should consult either LABC / Building Control or the Competent Persons Scheme you use (Fensa/Certass etc), to establish exactly what they will be looking for when they conduct inspections.
For new build you should consult with the developer and ensure that they make you aware of what they require from the windows and doors which need to be installed.