C is for...

Climate control

An extension of standard air-con, climate control basically adds a thermostat, so it maintains your desired temperature throughout the cabin by constantly altering the flow and temperature of the air.

The latest set-ups even let you tailor the cabin temperature for individual passengers. Typically, this is called dual or bi-zone climate control, with separate switches on each side of the dash.

On smaller cars like city models and superminis, we’d happily not bother upgrading from air-con to climate control, but it’s far more desirable if you’re buying in the executive or luxury class. Even so, fitting it won’t add much to the future resale value. Air-con is one of the most desirable extras on any car, but climate control carries a small premium; add it only if you want the convenience.

The system is generally maintenance free, but you’ll need to top up the refrigerant after a few years. It’s worth noting that leaving the air-con off for extended periods is bad news. This allows mould and bacteria to grow within the system – resulting in nasty smells and inefficient operation. To maintain its effectiveness, fire up the air-con frequently: for 10 minutes, once a week, as a rough guide.