Addressing the Growing Issue of Overheating in Homes
Introduction
As climate patterns shift, the issue of overheating in homes has become increasingly prominent. Rising average temperatures, particularly during the summer months, are a significant factor. Coupled with modern architectural trends favoring extensive glazing, improved insulation, and low air permeability rates, homes are retaining more heat. This can lead to uncomfortable living conditions and poses health risks, particularly for the most vulnerable members of society, such as the elderly and those with pre-existing health conditions, who are more likely to be at home during peak daytime heat.
Understanding Overheating Risks
The Role of CIBSE TM59
To address the problem of overheating, the Chartered Institution of Building Services Engineers (CIBSE) has developed TM59, a methodology for assessing overheating risk in residential buildings. This assessment should ideally be performed at the design stage through Dynamic Thermal Modelling (DTM), which provides a detailed analysis of how a building will perform under various thermal conditions.
Approved Document O: Overheating Mitigation
Introduced on June 15, 2022, Approved Document O sets the standards for overheating mitigation in new residential buildings. Compliance can be demonstrated through two methods:
Overheating Risk Assessment
An Overheating Risk Assessment is crucial in determining the likelihood of a building overheating. This desk-based assessment is guided by Approved Document O and can be conducted using either the Simplified Method or DTM.
Simplified Overheating Risk Assessment
This method is less complex and less costly compared to DTM. It focuses on limiting solar gain and ensuring adequate heat removal by analyzing factors such as window sizes, free area of openings, orientation, and cross ventilation. For most residential projects, this method suffices to demonstrate compliance with Approved Document O.
Dynamic Thermal Modelling (DTM)
For more complex projects or those that fail to comply using the Simplified Method, DTM offers an in-depth analysis. It evaluates internal temperature risks on a room-by-room basis, allowing for design alterations to mitigate overheating. Ideally, this assessment should occur before construction to integrate necessary changes into the building process.
Mitigating Overheating Risks
Approved Document O outlines several measures to reduce overheating risks:
Limiting Solar Gains:
Removing Excess Heat
As climate patterns shift, the issue of overheating in homes has become increasingly prominent. Rising average temperatures, particularly during the summer months, are a significant factor. Coupled with modern architectural trends favoring extensive glazing, improved insulation, and low air permeability rates, homes are retaining more heat. This can lead to uncomfortable living conditions and poses health risks, particularly for the most vulnerable members of society, such as the elderly and those with pre-existing health conditions, who are more likely to be at home during peak daytime heat.
Understanding Overheating Risks
The Role of CIBSE TM59
To address the problem of overheating, the Chartered Institution of Building Services Engineers (CIBSE) has developed TM59, a methodology for assessing overheating risk in residential buildings. This assessment should ideally be performed at the design stage through Dynamic Thermal Modelling (DTM), which provides a detailed analysis of how a building will perform under various thermal conditions.
Approved Document O: Overheating Mitigation
Introduced on June 15, 2022, Approved Document O sets the standards for overheating mitigation in new residential buildings. Compliance can be demonstrated through two methods:
- Simplified Method: This involves designing homes with specific glazing and ventilation parameters to limit heat gain and enhance heat removal.
- Dynamic Thermal Modelling (DTM): Using CIBSE TM59, this method provides a comprehensive analysis of the building’s thermal performance.
Overheating Risk Assessment
An Overheating Risk Assessment is crucial in determining the likelihood of a building overheating. This desk-based assessment is guided by Approved Document O and can be conducted using either the Simplified Method or DTM.
Simplified Overheating Risk Assessment
This method is less complex and less costly compared to DTM. It focuses on limiting solar gain and ensuring adequate heat removal by analyzing factors such as window sizes, free area of openings, orientation, and cross ventilation. For most residential projects, this method suffices to demonstrate compliance with Approved Document O.
Dynamic Thermal Modelling (DTM)
For more complex projects or those that fail to comply using the Simplified Method, DTM offers an in-depth analysis. It evaluates internal temperature risks on a room-by-room basis, allowing for design alterations to mitigate overheating. Ideally, this assessment should occur before construction to integrate necessary changes into the building process.
Mitigating Overheating Risks
Approved Document O outlines several measures to reduce overheating risks:
Limiting Solar Gains:
- Fixed Shading Devices:
- Shutters
- External blinds
- Overhangs
- Awnings
- Glazing Design:
- Optimal glazing size
- Strategic orientation
- Low g-value glass
- Deep window reveals
- Building Design:
- Placement of balconies
- Shading from adjacent buildings or landscaping
Removing Excess Heat
- Natural Ventilation:
- Sufficient openable window areas, especially enhancing cross-ventilation
- Natural ventilation louvres in external walls
- Mechanical Ventilation:
- Adequate ventilation rates through mechanical systems such as MVHR (Mechanical Ventilation with Heat Recovery)
- Mechanical Cooling Systems:
- If all other measures are insufficient, mechanical cooling should be implemented.
Our Services
We provide comprehensive Overheating Assessments for both commercial and domestic developments. Our expert team is dedicated to helping you navigate your requirements and ensuring you meet all necessary regulations to pass building control.
With our experience in the industry, we understand the commercial demands of a project and are committed to finding cost-effective solutions while adhering to government and building control regulations.
Contact us today to discover how we can deliver a fast and reliable overheating assessment.
Our pragmatic approach to overheating risks includes tailored assessments to meet your specific needs, such as:
- CIBSE TM59 Dynamic Simulation Modelling
- CIBSE TM52 Dynamic Simulation Modelling
- Simplified Overheating Risk Assessment
Leveraging our experience in overheating risk assessment, we provide services customized to your unique requirements. Often, a Simplified Overheating Risk Assessment is sufficient to meet compliance.
By addressing overheating risks early in the design process, we can help you create comfortable, safe, and energy-efficient buildings that can withstand rising temperatures. Get in touch with us today to learn more about our overheating risk assessment and mitigation services.
Links:
https://www.elmhurstenergy.co.uk/find-an-assessor/
https://designbuilder.co.uk/
https://www.futurehomes.org.uk/avoid-overheating
https://www.gov.uk/guidance/approved-document-o-overheating-frequently-asked-questions