Overheat Analysis

Overheat Analysis is part of our Detailed Design service and includes powerful visualisation and calculations (Dynamic Simulation with IES-VE). 

Overheating is more and more of a risk in new builds, even in Scotland. We can assess the design choices for shading, glazing, blinds and ventilation to allow compliance with guidance such as CIBSE TM52.

This saves money on unnecessary mitigation measures and may avoid the use of air conditioning systems say. 

Building Services

Overheating Analysis

Overheat visualisation
Overheat visualisation


Overheating is a becoming more of a problem in building design. As we use ever more insulated buildings with tightly controlled ventilation there is an increased risk of discomfort  particularly in the summer months or night time in bedrooms.

The industry has developed guidance such as CIBSE TM52 (“The Limits of Thermal Comfort: Avoiding Overheating in European Buildings 2013”), CIBSE KS16 (“How to manage overheating in Buildings”) and CIBSE TM49 (Future weather data) and Building Bulletin 01 (“Guidelines on ventilation, thermal comfort and indoor air quality in schools”). 

Overheat Study

Overheating is a measure of:

  • Number of hours in a particular room that is occupied that exceeds a likely “comfort temperature”
  • Severity of overheating- i.e. a measure of the temperature rise and duration
  • An absolute maximum temperature within a given daily period

In simple terms, a good test is to think “how comfortable would it be to sleep in that bedroom on a hot summer day …”!

Overheat analysis showing room temperature for different mitigation strategies

Overheating Study

Overheating is a measure of how you may feel (“operative comfort”) in your building. Thermal comfort is complex and dynamic (constantly changing), thus it makes sense to use a dynamic simulation model to predict the all the factors. The basic physical factors are air temperature; radiant temperature; humidity and air movement. We also model users (assumptions on clothing and activity) and their behaviour (for example they may open a window or draw down a shade or blind). 

Although it is difficult to give a precise risk at a particular time as the phenomenon is inherently imprecise, by looking at the factors in detail we can give an good statistical indication of risk of a particular room overheating. 

This allows choices about reflective glass, blinds and which windows to be fixed or openable a more scientific basis in the design process. It’s all part of having a healthy home.

See also this case study.

"the thermal modelling should ideally be able to predict the variations in temperature distributions and airflows within rooms, and also simulate the ventilation and other adaptive behaviour of the occupants"

CIBSE TM52 “The Limits of thermal comfort: avoiding overheating in European buildings”

Energy is complex!

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Lùths Services are an independent services engineering consultancy who specialise in low energy and renewable design and implementation. 

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