New Approved Document Part O: Overheating

Overheating in homes has become an increasingly important issue. With glazing systems achieving greater thermal performance ratings and homes becoming much more insulated, residential dwellings face the risk of creating uncomfortable living temperatures during warmer months.

The Government’s New Approved Document, Part O (Overheating) looks specifically at addressing this issue of overheating. The document applies to new build homes and buildings where people sleep overnight, leaving pre-existing buildings and commercial spaces unaffected.

The document holds two methods of compliance:

  • The Simplified Method: this method considers the size and orientation of glazing and compares the glazing area to the floor area. Window opening areas are also considered, to deliver suitable purge ventilation
  • Dynamic Thermal Analysis (CIBSE TM59): this can be used to ensure dwellings comply with the document by predicting the risk of overheating and offering a range of strategies for reducing this risk

Approved Document O: Key Findings:

  • Most single aspect apartments will fail the simplified method
  • Houses with crossflow can pass the simplified method, but window openings likely to need to be increased
  • Schemes with communal heating system can not be assessed via the simplified method

As a result of the above, the demand for TM59 overheating assessments will increase.

Listen In: MailOnline Podcast

Our Director of Energy Services, Andy Mitchell, joins The Andrew Pierce Show Podcast on the MailOnline to discuss changes to Building Regulations and Overheating. Listen now to hear the full discussion, from 11 minutes in.

Listen now: Building Regulations and Overheating Podcast

Read all about it: Telegraph article

Andy Mitchell also spoke to The Telegraph on how the Government’s new Approved Document O will affect the number of conservatories in British homes. Click here to read the full interview -

Read now: Building Regulations and Overheating

How does Part O affect your project?

Get in touch with our Built Environment team now to learn more about how the new building regulations and Part O will affect your project:

Overheating Risk Analysis

Stroma Built Environment offers Overheating Risk Analysis during the design phase to advise clients on mitigation measures to prevent overheating in buildings. With a team of experienced and qualified Energy Assessors, we can help assess potential overheating risks and develop robust solutions to improve performance.

Visit the Overheating Risk Analysis page now.