It's 36 degrees outside. You've got the aircon cranked to 18 in the van. Every stop, you open the door into a wall of heat, walk to the front door, walk back, and climb into the cold again. You do this 130 times a day. By Friday, your throat's scratchy, your nose is running, and by Monday you're calling in sick. Sound familiar? The hot-cold cycle is one of the least talked about but most common health issues for delivery drivers — and it's almost entirely preventable.
Why It Happens
Your body regulates temperature constantly, but rapid and repeated swings between extremes stress your immune system. When you go from a cold van into hot air and back 100+ times a day, your nasal passages dry out in the aircon, then get hit with humid outside air, then dry out again. This constant irritation makes your respiratory system more vulnerable to viruses and bacteria. According to Healthdirect Australia cold and flu guide, upper respiratory infections are the most common illness affecting working Australians.
Aircon also recirculates air inside the van. If the cabin filter is dirty — and in most work vans it hasn't been changed in years — you're breathing dust, mould spores, and whatever bacteria have been growing in the system. Add in the fact that you're touching parcels, door handles, intercoms, and your face all day, and the germ exposure is significant.
The dehydration factor makes it worse. Aircon dries the air, and most drivers don't drink enough water during a shift. Dehydrated mucous membranes are less effective at trapping and fighting pathogens — so you get sick more easily and recover more slowly.
Alternatives and Prevention
Raise the aircon temperature. Instead of blasting at 18°C, set it to 24–25°C. The goal is comfort, not refrigeration. A smaller temperature gap between inside and outside means less shock on your body at each stop. You'll still be cool enough to work comfortably.
Use fan mode between stops. If you're doing quick residential stops (30–60 seconds each), switch to fan-only or fresh air mode instead of full aircon. This circulates air without the extreme cooling. Save the aircon for longer drives between suburbs.
Open the windows. On milder days (under 30°C), windows down is genuinely better for your health than aircon. You get natural airflow without the drying effect, and your body temperature stays more stable. Yes, it's less comfortable — but you'll get sick less often.
Change your cabin filter. If you're an owner-driver, change the cabin air filter every 15,000–20,000 km or every 12 months. If you're in a company van, ask your fleet manager when it was last done. A clean filter dramatically improves air quality inside the cab.
Stay hydrated. Drink at least 2–3 litres of water during your shift. Not energy drinks, not coffee — water. Hydrated airways fight off infections more effectively. Keep a water bottle in the cab and sip throughout the day, not just at breaks.
Cooling towel. A wet cooling towel around your neck is surprisingly effective. It keeps your core temperature manageable without aircon and works well on the walk between the van and the door. They cost $10–$15 and last all season.