Air con is not just for summer

If you don't use your air conditioning year-round, it can be bad for your health - and your wallet, says James Ruppert

You only realise how important air conditioning is when it is not there anymore. During a recent (brief) heatwave, my own in-car cold air went missing. At first there was a sound like a flatulent Victorian plumbing system, then there was some dry ice through the air vents and then there was nothing except tepid air. It was hell in there.

You only realise how important air conditioning is when it is not there anymore. During a recent (brief) heatwave, my own in-car cold air went missing. At first there was a sound like a flatulent Victorian plumbing system, then there was some dry ice through the air vents and then there was nothing except tepid air. It was hell in there.

I am not alone. Apparently air-con failure is up by 55 per cent over the past 18 months. According to data released by the independent automotive warranty specialist Warranty Direct, one in 20 claims is now air-con-related, with the cost of repair being fairly substantial. On average, owners will face a bill of £444.68, making the air-con unit the fourth most expensive item to repair after the automatic gearbox, turbo and engine.

That's not too surprising because it is a complex system. First, there is the compressor, which is powered by a drive belt from the engine, pressurising the gas. The condenser is located in front of the radiator. Through the use of cool airflow provided by the engine fan, the condenser cools the hot gas and converts it to liquid. Next an expansion valve takes the liquid and depressurises it - which makes the temperature drop. As the cold liquid leaves the valve, it is fed to a heat exchanger under the dash that blows warm air from the car interior across it. The cold liquid refrigerant is what cools the air you feel coming out of the ducts. As the air is cooled in the heat exchanger, the liquid refrigerant is heated in the other side of the heat exchanger and then it evaporates.

That is the technical explanation and it is worth remembering that, as well as ice-cool air, you can also have air-conditioned warm air by selecting heat at the controls. In the winter months that is the quickest way to clear your screen of condensation. One important function of an air-con system is that the cooling component also removes moisture from the air as it passes through, along with other contaminants in it, such as pollen and pollution. This moisture then drains out underneath the car.

There is also a subtle distinction with air conditioning where the driver decides how much cool or warm air is needed in which direction and at what rate. A climate-control system uses thermostats and a computer to do all this automatically; the driver just enters the desired temperature and the system maintains it, regardless of changing temperatures outside. It can be operated manually as well, but is another indication as to just how complicated these systems are.

The Warranty Direct research indicates that the air-con units on some models look less reliable than others, as the Volvo 850 reports a failure rate of 37 percent and the Ford Galaxy nearly 27 percent, but the underlying problem is that too many motorists fail to see the importance of servicing.

"Too many people treat air con as a fit-and-forget option," warns Warranty Direct's Duncan McClure Fisher. "Units need regular use and regular servicing to help prevent expensive breakdowns. An annual health check and service should cost about £40 from an independent specialist, a far cry from the pre-fit £920 it would cost to buy an air-con compressor unit on a Toyota Land Cruiser Amazon."

The vehicles most susceptible to failure are those aged four years and over - which is significant because that is when the manufacturer's warranty runs out, along with regular maintenance of the air-con system. Using your air-con system at least once a week will reduce this risk of failure. Climate-control systems are less likely to be a problem, because they tend to be used all-year round, as the ideal temperature is simply programmed in.

Comma, a car-care products supplier, has researched the problem and discovered that more than a third of all motorists admit to never using their air con outside the summer months. Surprisingly, they also found that two in five of those surveyed do not consider air con to be an essential feature for their vehicle. Rather scarily, if it is not used throughout the year, it can quickly become a breeding ground for Sick Car Syndrome triggering fungal spores such as Cladosporium and Aspergillus.

"Most people associate air con with summer, but it is equally important to use during the colder months as well," says Comma spokesman Mike Bewsey. "Once established, the bacterial spores quickly multiply to deliver a rather nasty, lingering smell in the car, something buyers of used cars will instantly recognise."

Comma of course can come to the rescue with its own brand of Air Con Cleaner which contains a biocide that helps eradicate the festering bacteria, fungi, mould and even viruses such as E-coli from the air-con unit.

Not looking after your air-con system could seriously damage your health, so a little squirt of an aerosol to clean and deodorise the system is the very least we should be doing. Comma research revealed the worst offenders for not looking after their air-con system are motorists over 55, with 50 per cent readily admitting to limited summer use. In comparison, drivers of cars under a year old are the most likely to continually use air-con, with 72 per cent keen to keep their new car in tip-top condition.

If you've got an air-con system you had better look after it. Otherwise, it could hit you where it hurts, with a nasty smell up your nostrils and a sinking feeling in your wallet.