What is the coldest temperature for an air conditioner?

A question sometimes asked by people considering domestic air conditioning systems for their home is what the coldest temperature is for an air conditioner? Just how low can you set the temperature when you’re operating your air conditioning unit for it to work effectively and efficiently.


Will running AC in cold weather damage it?


Running an air conditioner in cold weather, perhaps during a British winter, is never a good idea. Air conditioners that contain condensing units are not designed to be run in cold weather at all. The units contain heavy grade oil that lubricates the compressor. This oil works best in warm conditions and during cold weather it becomes thicker. This means that it won’t be lubricating the compressors properly.


If an AC compressor contained a lighter grade oil, then it would work more efficiently in the winter but would present problems during the summer when it could heat up to the point where it wouldn’t provide enough lubrication.


Another potential problem with using an air conditioner in very cold weather is that if condensation forms on the cooling coil, it may then freeze causing damage to the unit.



What temperature is too cold for air conditioning?


As a general rule of thumb, HVAC manufacturers usually recommend that users don’t operate units for prolonged periods of time if the temperature is below 16-18 degrees Celsius. If you wish to test your unit then you should wait until the temperature has reached 16c for a few days beforehand. This allows the oil to warm up and should ensure that there’s no ice built-up on the condenser.


Most modern units will be fitted with a sensor that prevents the system from running in the cold, but older units often do not. With this in mind, it can be advisable to test, maintain and carry out any repairs of your unit once the risk of very cold weather has passed.



Setting the air conditioner temperature


If you’re setting your air conditioner in cooling mode, doing so at lower than 21C will normally be regarded as too cold to have much impact and is generally wasteful of electricity. Likewise, if you’re attempting to heat a room that’s already at 24C, this too is an inefficient and costly use of an air conditioning system.

Generally speaking, most people set their central heating thermostat at around 22C, so setting your air conditioner to the same temperature is sensible.



A regular servicing and maintenance service


Regular servicing and maintenance of your air conditioning unit can extend its life and improve its performance. At Enviro Chill, we offer affordable maintenance packages for both domestic and commercial installations.


Call 0151 2851818 or contact us online.