4 HVAC Odors - A Guide to Identifying and Eliminating Them

Your home’s heating, ventilation, and air conditioning (HVAC) system is a functional appliance that makes your life more comfortable. Since this unit provides you and your family with so much convenience, it should undergo regular maintenance and repair.

Sometimes, you may encounter problems with your HVAC system, such as a nasty odour coming from your unit. This can happen due to a wide range of reasons, including a dirty air filter or mould. To determine the real cause of your issue, here are some common HVAC odours and the ways on how to identify and get rid of them for good:

  • Mouldy or musty smell

One of the most common odours in HVAC units is the smell of mildew or mould. This occurs when there is a lot of condensation within your air conditioner and the moisture accumulated and gets trapped into the ducts, causing mould to form.

If there is a musty smell coming from your HVAC unit, you can easily manage the odour by searching the mould buildup’s location first. Make sure to clean it up thoroughly as soon as you spot the mould. For best results, consider hiring our HVAC technicians and seek help from our top-notch air conditioner repair in London, Ontario. We assure that your odour problem won’t occur again.

  • Rotten egg smell

The smell of rotten eggs or sulfur coming from your HVAC unit indicates a natural gas leak. When left unaddressed, this could lead to a more serious problem. Because of this, you have to take this seriously, open your windows, get out of your house right away, and call a gas company immediately. 

Feel free to reach out to our professionals who specialize in HVAC maintenance in London. We will provide you with an exceptional service by heading to your place as soon as possible, identify the cause of the rotten egg smell, and ensure this won’t be a recurring problem.

  • Gas smell

When you smell like gas is burning when you first turn on your heater, this could be a sign of a  leak at your pipe fitting or within your unit. This is caused by the dust getting burned off when the furnace is turned on. Make sure to call your HVAC technician right away and avoid attempting to address this problem on your own. This issue requires the expertise of a knowledgeable and skilled professional to find the leak and have it fixed in no time.

  • Electrical odours

Your HVAC unit can emit an unpleasant smell when your air filter gets too dirty. As a result, the airflow can get restricted and overheat the electric resistance heaters. Fixing this issue can be done by first turning your unit off and cleaning your air filter. Afterward, turn your electricity off at the master switch. When the problem persists, call an HVAC technician to assess your situation and make necessary repairs.


Troubleshooting your HVAC unit that produces a stinky smell can indicate a concern that could turn serious or dangerous when left neglected. Follow the steps mentioned above and get in touch with an experienced HVAC technician as soon as possible to ensure your safety and expand your system’s lifespan.

Get the best services heating and cooling in London, Ontario by turning to Donaldson Heating & Air Conditioning. We offer residential service and replacement, new home construction, and light commercial and agricultural services. Contact us today to request a quote!