If You Can’t Take The Heat…

…Then redesign the kitchen. Overheating in buildings is a growing issue.

We have become accustomed to the need in New Zealand for warmer, drier, healthier homes to protect us all from the effects of cold and condensation; and how very important this is. What we are just starting to get evidence of, is the impact of overheating.

Some of the very things that help us in cold weather, insulation and reduced air leakage, are the things that make the warm or sunny weather more difficult to handle. This is true whether we are thinking about homes, or hospitals, schools or hotels.

You’ll remember recent media coverage of overheated prison cells. Temperatures of up to 40°C were reported with subsequent health effects. These at face value, were in part due to the buildings used to house prisoners not being designed to withstand the climate at the height of Summer.

Overheating isn’t just an issue in prisons. It’s happening in homes.

Those who are vulnerable to heat, whether through health conditions or illness, old age or immaturity, can find that their homes are just not able to provide them with a cool enough environment. A death of a woman in Christchurch, through hyperthermia associated with her health and the weather, was noted only last month and if the experience of other countries is anything to go by we really do have something to worry about.

UK research suggests that around 2,000 deaths per year are attributable to overheating and predicts this could rise to 7,000 by the 2050s. In the heatwave of 2003, 20,000 deaths across Europe were heat related with 2,000 of them in England alone.

Classroom with fanHere in New Zealand we typically have higher Summertime temperatures than the UK, more sunshine in general, and buildings more susceptible to heat coming in (larger windows, less thermal mass, lower insulation). If we follow even the same proportions we could be looking at nearly 500 heat related deaths per year by the 2050s here.

We’re seeing effects on our schools too. Whilst they do their best to proactively respond to the heat and remain open, the ability of children to learn and staff to teach can be severely impaired.

Across the globe there is a similar story with hospitals, apartment buildings, and mother and baby units, retirement homes and others all being affected.

So, what can we do?

The first thing is to recognise the issue as being one of concern. We really don’t want the solution for cold, damp homes and buildings to bring about other issues. People deserve to live, learn, work, heal, and play in indoor environments that give them the best. At the very least they should expect not to struggle in them.

InsideOut is well used to the often competing issues of design which call for warm, dry environments in Winter and cool airy environments in Summer. These obviously come with a requirement to avoid burning energy where it is not needed. What we need to do is design the problem out.

What do we look at?

• Architecture: Orientation, form, aesthetic
• Climate: location, temperature, radiation, wind, cloud, humidity
• Thermal envelope: window to wall area ratio, insulation, glazing and joinery
• Passive design: external shading, thermal mass,
• Ventilation: air tightness, natural ventilation and openings, mechanical extract and supply
• Function and controls: occupation periods, control protocols, set-points
• Energy: solar gain, conduction heat loss, heat recovery, internal gains
• Outcomes: Thermal comfort, humidity, condensation, indoor air quality, daylight, energy

Melted candles in SummertimeUsing simulation software (and sometimes monitoring for an existing building) it becomes possible to navigate through the many options for a design and find the one which works best for you; fits the budget; meets the aesthetic; and provides the function. This is InsideOut’s bread and butter (as long as it hasn’t gone runny in the heat!)

There’s plenty of evidence. Here are reports of just a little…


Prison-moves-to-ease-overheated-cells-after-inmates-make-complaint Naturally ventilated hospital ward




Overheating at maternity unit



Author: Ruth Williams – Principal, Buildings That Work InsideOut Ltd

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