Heat in Cars

Heat in Cars

During the warmer months it's a good time to remind ourselves about the dangers of locking children or pets in cars parked outside, particularly in bright sunlight.

It’s often tempting to do this, perhaps to pop into a shop for just a few minutes, without all the hassle of buckling and unbuckling seatbelts and arranging prams and strollers.

However even a short time can be extremely dangerous, particularly during the summer months. Tests have shown that on a 30C (86F) day, as measured in the shade, a car parked in the sun can heat up from 20C (68F) to 44C (111F) in only ten minutes. After 20 minutes, temperatures inside the same car can hit 60C (140F).

Temperatures can ramp up to 60C (140F) inside a car parked in the sun in less than half an hour.

The shape of the car, its colour, interior type and the amount of window and windscreen glass also affect the way the vehicle heats up, as do other variables such as cloud cover, wind and the angle of the sun. But the effects of these are usually quite minor and any vehicle parked outside on a hot day will heat up quickly. And contrary to popular opinion, leaving the windows partially down does not solve the problem – it may just slow the heating process slightly. There is no safe way to do it.

Even hi-tech modern vehicles, such as this Honda Civic, can heat up to dangerous interior temperatures when parked outside during bright sunlight conditions. (Image from Wikipedia Commons - click to enlarge)

But perhaps of even greater significance is that controlled tests have also revealed that we don’t need very hot weather to produce dangerous temperatures inside cars; even in mild conditions of around 22C (72F), interior temperatures can rapidly ramp up to 40C (104F) plus in less than an hour in bright sunlight conditions.

Small children confined in these sauna-like temperatures can dehydrate rapidly, and suffer an onset of hyperthermia, where the core temperature of the body rises to dangerous levels, above 40C (104F) on occasion. This can create a serious and sudden medical emergency with hospitalisation required, and in extreme circumstances fatalities have occurred.

In the United States, where these figures are readily available, more than thirty children die each year of heatstroke, after having been locked in cars parked outside. There are probably numerous examples of pets dying under similar circumstances.

So the summer message is clear – don’t expose your children or pets to these risks, even for a short period of time.