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It's getting hot in here. So take off all your clothes

It's getting hot in here. So take off all your clothes' ... so sang [insert sarcastic tone here] seminal early

noughties rapper Nelly in his 2002 smash, Hot in Herre (apparently the extra 'R' indicates it was really hot - who knew?).

Whilst some may be disappointed that Nelly's suggestion for tackling overheating in buildings has been widely ignored, a new Building Regulation requirement to tackle the issue has been introduced - PART O .

Joking aside, overheating in buildings is a serious issue, the Governments publication Heatwaves: adapting to climate change, published in 2018 [available here: Heatwaves: adapting to climate change ( ] stated,

In the August 2003 heatwave temperatures reached 38.5°C in England, and there were 2,193 heat-related deaths across the UK in just 10 days.

The report goes on to say that 'The average number of heat-related deaths in the UK is expected to more than triple to 7,000 a year by the 2050s'.

To tackle this issue new Building Regulations, have been made under the The Building Regulations etc. (Amendment) (England)Regulations 2021, these come in to force on 15th June 2022. The Regulations (the legal functional requirement) are accompanied by a new Apporved Document (the technical guidance that supports the Regulation).

A copy of Apporved Document O can be found here: Overheating: Approved Document O (

The Regulations which apply to residential projects (but not hotels), essentially seek to,

  • to limit unwanted solar gains

  • provide means of removing heat

  • give sufficient information to the owner in relation to the overheating mitigation strategy (Regulation 40B)

It's interesting to note that Regulation O(2) a. states that,

account must be taken of the safety of any occupant, and their reasonable enjoyment of the residence

Further guidance is provided in how to meet this in relation to noise, pollution, security, protection from falling and protection from entrapment.

Transitional provisions have been provided, this means that the new requirements do not apply if a building regulations application is given prior to the 15th June 2022 and work begins on that particular building before 15th June 2023.

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