Should you use your air-con in the winter?

There are plenty of myths around air-con, but what should you really be doing?

Getting the system re-gassed, is often the best way to keep your air-con in top form, as well as ensuring you use it all year round, but there are plenty of other things to consider too.

Here, in this car maintenance guide, we look at people's top air-con issues, separating fact from fiction.

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Winter air con at a glance

Should I use the air-con in winter too?

In a word, absolutely. In fact consider it an essential part of car maintenance that could directly save you money on repair work further down the line.

First and foremost using warm air from the system in winter is a great way to demist the windows.

The air coming out of the vents is dry, so the air-con acts as a dehumidifier.

If air conditioning is left unused for long periods, seals can dry out, refrigerant may slowly escape and moving components such as the compressor clutch can be more prone to problems.

The air-con is filled with a refrigerant and some oil, and it pays to keep that liquid flowing and the components of the system lubricated.

Why does my air-con smell?

If you've noticed a musty or unpleasant smell coming from your car's air conditioning, you're not alone. A smelly car air-con system is usually caused by bacteria, mould and moisture building up inside the ventilation system, particularly if the air conditioning hasn't been used regularly.

When the system is switched on, these contaminants can produce a damp or stale odour through the air vents. The problem is often more noticeable after the car has been sitting unused for a while or during warmer weather.

To get rid of bad smells from your car air conditioning, try using an air-con antibacterial cleaner or disinfectant treatment designed for vehicle ventilation systems. Replacing the cabin air filter can also improve air quality and airflow if it's become clogged with dust, pollen and debris.

The best way to prevent a smelly air-con system is to run the air conditioning regularly throughout the year, even in winter. This helps keep the system dry, reduces the build-up of bacteria and mould, and keeps the components in good working order.

READ MORE: Car smells guide – causes and solutions

Should I drive with the windows open when the air-con is running?

While the cool blow of the air-con does its job, for many drivers the temptation of feeling that ‘fresh air’ on their faces doesn’t go away.

While you’re unlikely to cause too much in the way of genuine damage to your system, it’s generally not recommended to travel for too long with both your window open and your air-con on.

Primarily, it’s not economical. If the air-con is running, closed windows will keep the cool air inside the car and keep the temperature moderate.

What’s more, the open windows let warm air inside the car, which also puts stress on the air-con system potentially leading to problems.

As a rule of thumb, if it’s hotter and more humid outside the car than it is inside, you’re losing out to have the air-con running with the windows open.

Which is more efficient – air-con or open window?

An age-old debate. The reality is, neither helps your fuel efficiency.

At lower speeds, opening the windows is often more economical than using air conditioning.

At motorway speeds, open windows can increase aerodynamic drag sufficiently that air conditioning may be the more efficient option.

• How to demist your windscreen in double-quick time
• How to save fuel - the ultimate guide
• A complete guide to driving safely in snow

My aircon is not as cold as it used to be – what's wrong?

If cooling performance has declined, the system should be inspected. A regas may solve the problem if refrigerant levels are low, but other faults may also be responsible.

However, your first step could be a regas.

This involves removing the old refrigerant gas from the system and replacing it with new refrigerant. This should take a specialist no longer than an hour to do.

Your A/C system is complicated, and while there are some easy fixes like recharging the refrigerant gas, there are also more difficult issues that only a trained or certified mechanic can fix.

In a few cases, the problem is indicative of more severe issues, but usually repairing the A/C is a simple job, even when an RAC Mobile Mechanic should handle it.

Why is there a pool of water under my car?

This is a summer issue, but still one people frequently ask.

If the weather’s hot and you’ve been using the air-con – panic over, this is quite a normal situation.

During the summer, your air-con compressor has to work harder and the unit itself can actually freeze over, as it sucks the moisture out of the car.

So as soon as you park and switch off the air-con, the ice that’s formed on its surface starts to melt, drip and form a troubling puddle under your car.

Our advice is if it’s simply odourless water there should be nothing to worry about. If it has a clear smell and colour (of coolant), it could be something more serious.

If your MOT is due or if you would like to book your vehicle in for a full car service, you can book online with your local RAC Approved Garage today.

Does air conditioning affect electric vehicle range?

Yes, using air conditioning can reduce an electric vehicle's driving range, as the system draws power directly from the battery. However, in most real-world driving conditions, the impact is relatively small and is unlikely to make a significant difference to longer journeys.

Modern EVs are designed to manage energy use efficiently, and the reduction in range from running the air conditioning is often outweighed by the benefits of a more comfortable cabin, especially in hot weather.

One way to minimise the effect on range is to pre-condition the vehicle while it's still plugged in and charging. Many electric cars allow drivers to cool the cabin before setting off, meaning less battery power is needed once the journey begins.

It's also worth noting that cooling the cabin with air conditioning generally uses less energy than heating it in cold weather. Many newer EVs are fitted with heat pumps, which are more efficient than traditional resistive heating systems and can help reduce the impact on driving range throughout the year.

As with petrol and diesel cars, there's no need to avoid using air conditioning altogether. The comfort, visibility and safety benefits typically outweigh the small reduction in efficiency.

Video - how to avoid a winter breakdown