Ask Honest John Question of the Week: Is it better to use recirculation when using air conditioning?

David Ross, Editor
Fri, 10 May 2024

Dear Honest John,

"Is it true that you should have your recirculation button on all the time in summer when you are running the air conditioning?"

- KH

Dear KH,

Using the recirculation button in conjunction with your air conditioning can result in a consistently lower temperature, as the system is chilling the air from the cabin which is already cold rather than having to cool fresh air from outside, which is likely to be a higher temperature.

However, there are a few other things you can do to get the most out of your air conditioning system in hot weather.

If you are getting into your vehicle and the cabin is already hot, it is best to open all the windows at the start of your drive to allow the hot air to escape. Although the external air may still be hot, it will still be cooler than the trapped air inside your car, and this gives your air conditioning a helping hand.

Leaving the recirculation function activated allows the air conditioning to operate more efficiently, but after a period of time you may wish to deactivate it for a while to allow fresh air to enter. This prevents the interior from become stale, which may be unpleasant for your passengers and can also cause the windscreen to become fogged.

As well as ensuring your air conditioning system is serviced and the gas replaced as appropriate, we would also recommend using the system at least on occasion in colder months to ensure it is working correctly.

Keeping it switched off for eight months of the year increases the likelihood of component failure when you need it most, and although it may mean a slight increase in fuel consumption this is likely to be less expensive than replacing a seized compressor.

Ask HJ

Is an air conditioning service necessary?

My Toyota dealer recommends that I have my air con serviced after only two years. They quote £150. Is this necessary?

If the air conditioning is running cool and isn't showing signs of problems then I personally wouldn't bother. That said, you may want to check the air con service isn't written into your car's warranty or the terms and conditions of your finance agreement (should your car be on PCP or lease). The best way to keep your air con in tip-top condition is to keep it switched on 100% of the time. Most problems occur when drivers switch the system off for the winter months, which results in the system drying out and/or the compressor seizing up.

Answered by Dan Powell

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