Why does my UK new-build home suffer with overheating in the Summer?
As the UK experiences hotter, drier summers and more frequent heatwaves, the issue of overheating in buildings has become increasingly critical. While we often focus on heat retention during construction and renovation, we must also address overheating to ensure comfortable living conditions. In this blog post, we’ll explore the causes of buildings at boiling point, the new Part O building regulations, and effective strategies to mitigate this problem.
What are the causes of overheating?
Overheating occurs when indoor temperatures become uncomfortable for occupants over an extended period. Several factors contribute to overheating:
Inadequate Central Heating Controls
Poorly regulated heating systems can lead to excessive indoor temperatures.
Poor Ventilation
Insufficient airflow prevents heat dissipation. Adequate ventilation strategies whereby air is exchanged frequently and can be temperature controlled by means of passive or active cooling can really help tackle overheating.
A good example of this would be a summer bypass on the heat exchanger on a MVHR system.
Proper installation, testing and commissioning of ventilation systems is vital. Learn more about our ventilation services here.
Large Glazed Areas
Uncontrolled solar heat gain through extensive windows exacerbates overheating.
Poor Air Tightness
Warm summer outside area can infiltrate buildings. If the building has a poor air tightness, more of this warm air can enter the building unknowingly. We can determine infiltration rates by carrying out Air Tightness Testing.
Poor Internal Air Quality
Linked with ventilation and air tightness, humid conditions can worsen the discomfort by heat. By actively managing moisture generation can massively help tackle overheating. Learn more about our air quality services here.
Part O: Overheating Building Regulations
Introduced in England, Part O: Overheating focuses on reducing overheating risk in new residential buildings. It addresses unwanted solar gains and provides means to remove excess heat. However, it currently applies only to new constructions.
Dynamic Thermal Modelling TM59
How can you mitigate the risk of summertime overheating if you can’t measure it. The CIBSE Technical Memorandum 59 (TM59) offers a consistent methodology for assessing thermal comfort during design. Key features include:
Dynamic Thermal Modelling: Simulates internal temperatures to determine discomfort thresholds.
Adaptive Comfort Model: TM59 uses this model to set design comfort criteria.
Standardized Heat Gains and Occupancy Profiles: These help assess overheating risk.
Mitigation Cooling Strategies
To prevent overheating at development stages, consider the following measures:
- Design with Thermal Mass: Incorporate materials that absorb and release heat slowly, stabilizing indoor temperatures.
- Insulation and Airtightness: Proper insulation and airtight construction reduce heat transfer.
- External Shading: Install shading devices (e.g., awnings, louvers) to block direct sunlight.
- Maximise Natural Spaces: Utilize outdoor areas for cooling.
- Cross Ventilation: Design openings to allow natural airflow.
Remember that early analysis during the design phase is crucial. Collaborate with designers and consultants to holistically address overheating risks.
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As our climate changes, addressing overheating becomes essential. By combining regulatory compliance, informed design, and effective strategies, we can create comfortable, resilient homes that withstand rising temperatures.