My HVAC has started to smell: what could it be?

My HVAC has started to smell: what could it be?

By | 2018-07-05T06:26:48+00:00 June 25th, 2018|News|0 Comments

With the warmer weather you will have turned the air conditioning on in your home or office to make your surroundings more comfortable. In some cases, particularly where the unit has not been operating over the winter months, you may notice a smell coming from it. While this is not unusual, it will need to be investigated and dealt with before it becomes worse and there are certain instances where it could be dangerous. Our aim this month is to help you identify what may be causing any odours so that you can either deal with them or get an experienced engineer in to tackle them.

A musty or mouldy smell

Possibly the most common smell to come from an HVAC unit, a mouldy or musty odour is usually the result of a build-up of mould within the unit. This happens because of the condensation associated with running your air conditioning. When it cannot drain away properly, mould will build and lead to this odour. While it is not a serious problem for the unit, any mould spores that are present can be blown into your home and they are harmful to people as they can exacerbate allergies where they are present or lead to respiratory problems. If you can see the mould, clean it well and the problem will go away. If you cannot, call an engineer who can do it for you. You can keep the unit running while you wait for the engineer to come, but don’t delay calling them out.

An electrical smell

Often the result of settled dust over the winter which is now burning off, this will go away within half an hour if it is what is causing the smell. Alternatively, it could be due to overheating. If it does not disappear quickly, then turn the unit off.  The filters may need cleaning or replacing, or it could be a problem related to the wiring.  Contact us to book a callout, for an engineer to look at the unit.

A rotten eggs or gas smell

Both are the result of gas in which case you should turn the unit off, open the windows for ventilation, and call an engineer. If you are getting a strong odour of rotten eggs you should leave the house as well so that you are not breathing it in while the air coming in from the newly-opened windows ventilates the house.

An oil smell

This could either be the result of an oil leak or a problem with the oil burner. Both will need attention from a professional, but if you can see any oil pooling anywhere it will help them to pinpoint the problem.

Smell of dirty socks

It could be your teenager’s dirty gym kit, or it could be your HVAC system. With small homes, units are sometimes installed in tight spots with limited air so ventilation is a problem. The smell of dirty socks comes from a build-up of organic material which cannot be burned off if units have limited ventilation and can’t reach their optimum temperature. A trained professional will help you to identify and repair the problem.

If you notice any unusual odours from your HVAC unit let us know. One of our JP Air Conditioning professionals will come out to you to diagnose the problem. If we cannot fix the problem during the callout, we will then provide a quote for the recommended repairs. Call us on 020 8333 1191 or drop us a line at to make an appointment.

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