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Common Problems with Air Conditioning in Winter

Common Problems with Air Conditioning in Winter

During the winter months, we take multiple calls from customers experiencing issues with their air conditioning units.

While it’s true that heavy snow and sub-zero temperatures are not ideal operating conditions, some of the most common problems can be easily avoided.

In this post, we have outlined some of the most common problems people experience with their air conditioning in cold weather. We give you tips on how to act in the event of a fault and explain what you need to worry about, as well as what you don’t.

Winter Air Conditioning ProblemsWinter Air Conditioning Problems

The most common fault we see during the winter is poor heating duty, which is sometimes caused by equipment being insufficient to operate at low ambient temperatures.

This problem often arises from installers selecting incorrectly-sized or unsuitable units for the job.

To counter these issues, air conditioning manufacturers are working hard to develop systems that can perform at increasingly low ambient temperatures, without loss of capacity. Advances are being made all the time and air conditioning is becoming increasingly efficient during the winter months.

Generally speaking, manufacturers can now claim that new models can operate in heating mode down to -10ºC. However, putting it in such simple terms can be slightly misleading.

If, for example, you had a unit that produces 10kW heating at 5ºC, you could expect at least a 30% drop in efficiency if the temperature fell to -10ºC. There will be extra strain on your units but the temperature rarely gets that low in the UK.

Another common fault we encounter is high-pressure trips. These sometimes display on controllers as a common error.  When in heating mode, this particular trip is caused by dirty filters, which only reinforces the need to get your air conditioning units regularly cleaned and maintained.

Common False Alarms

Another issue with air conditioning units in the winter is that they can appear to develop problems without actually doing so.

Commonly, people see water leaking from their outdoor condensers and assume that something is wrong. However, while it may look disconcerting, particularly when the condensers are surrounded by melting snow and ice, it’s perfectly normal for that to happen when in heating mode.

The only time it becomes an issue is when there is a public walkway or footpath beneath the condensers. The leaking water can turn into a slipping hazard if it freezes. It’s important to divert the water and allow it to drain into a safe area.

Condensers are also more noisy than usual when the weather is cold, therefore if you notice additional noise, it’s unlikely to be anything to worry about.

When running in heating mode, air conditioning units stop producing heat from time to time. This allows the system to enter defrost mode, which is necessary to prevent ice and frost building up in the condenser coil. If you are not sure what is happening, it can be a worry, but wait to see if they start producing heat again before calling someone out.

Air Conditioning Problems in WinterPreventing Faults in Winter

There are several things you can do to prevent problems developing during the winter and a few quick fixes to try if anything does go wrong.

Always keep your units free from obstruction, making sure your system doesn’t have to work any harder than is necessary. That goes for outdoor and indoor units.

Make sure nothing is blocking indoor vents or air discharge points, enabling your system to run as efficiently as possible.

Set your controllers to a sensible temperature, bearing in mind the outdoor conditions. 23ºC is a reasonable temperature for normal working offices, while 30ºC (which we do come across from time to time) is excessive and puts unnecessary strain on your system.

One other thing to do when it is cold is to position the louvers on the indoor units as vertically as possible, ensuring heat is forced down quickly into the room.

If you encounter a fault code, our first suggestion is to switch off mains power, leave for 10 seconds and then restart. Most faults require manual resets, and, more often than not, they will resolve any trivial error codes.

It’s the first thing an engineer will try when they come out and it’s always more expensive that way! If you do need to phone in, make a note of your fault code as this helps us quickly determine roughly what the problem is.


If you are experiencing problems with your air conditioning, whether it’s the result of the cold weather or anything else, get in touch on 0141 773 3355.