Why Turn on Your Vehicle's AC During Winter, and Other FAQs

The cold days are coming, but that will not stop fleet drivers from doing their work. That means enduring the cold and driving through the snow. But how important is it to use one’s air conditioning unit during this time? How will it affect the performance of one’s vehicle? This winter season leaves some unanswered questions for these drivers, and this article will answer some of them.

Using the aircon in the winter: Is it necessary?

Yes. Using your vehicle’s air conditioning unit during wintertime can help you prevent repairs in the future. Here is what usually happens in a car: One, the system produces warm air inside the vehicle during the cold days, and it is great because it demists your windows. However, the air coming out of your vents is dry, so your air conditioning will act as your vehicles’ dehumidifier. 

Think of your vehicle as a human body. When the air conditioning system and other equipment or devices inside it are not used for a long while, it will seize up, and you will experience poor air circulation. Every aircon is filled with refrigerants and oil, so keeping the fluid inside it running can retain its good condition. Apart from that, make sure to lubricate the system regularly.

Smelly aircon: Is this normal?

Not using your AC for a while can lead to a mouldy smell coming out of it. Your aircon might have bacteria and mould buildup inside, which is what you will smell once you turn it on again for the first time. If there is a musty smell coming from your vents, clean them with an anti-bacterial cleaning product. Ensure you regularly change your cabin filter and use your air conditioner every now and then to prevent buildup.

Driving with open windows while the AC is running: Should I do this?

Driving with the windows open will not damage the vehicle, but it is generally not recommended that you drive too long with your AC turned on and your windows wide open for two reasons. 

First, it is not practical. When your vehicle windows are open, the cold air will not stay inside the car. Second, open windows allow warm air from outside to enter your vehicle. That could put a strain on your AC, which can lead to potential system problems. 

Here is a rule you need to remember when it comes to car temperature: If it is hot and humid outside, never turn your AC on with the windows open. You will only end up losing more if you do.

The AC is not as cold as it used to be: What to do?

The first thing you should do is regas. That means replacing the old refrigerant gas with a new one. Ask a specialist to do this, and the job will be done in less than an hour. In some cases, this particular problem can indicate other severe vehicle issues, so make sure to have your vehicle checked by a professional.


The relationship between winter and your car’s AC can be tricky at times, but once you understand how each part works, things will be easier to grasp. The rule of thumb is to keep all your vehicle’s features working as they should. That is how you keep your system in good condition.

Do you need heavy-duty vehicle air conditioning or other fleet vehicle services in Ottawa? Simplicity Air is a market leader in providing climate-based solutions for fleets. We install and service mobile HVAC units for on- and off-road vehicles. Contact us to learn more about our services.