7 Common HVAC Issues and Their Causes

Heating, Ventilation and Air Conditioning – or HVAC systems – are a common and integral part of the modern home. These systems are responsible for cooling, warming and aerating the home, office or commercial space, as required. HVAC systems usually require little maintenance for their smooth and efficient running. Though typically very reliable, they can have their own unique sets of problems. This can often be a costly or stressful experience, particularly if the issues aren’t dealt with quickly.

While a proper cleaning and maintenance procedure can assist in ensuring the HVAC system remains functional, safe and efficient, there are a number of issues to look out for such as:

– Odours
– Inexplicable increases in power bills
– Inconsistent heating and cooling
– Odd noises
– System failure or inadequacy
– Reduced airflow
– Air conditioner won’t turn off

When HVAC systems are causing any of the above difficulties, it’s best to fix it or have it seen by a professional as soon as possible to reduce further problems and expenses. Ensuring a quick response to HVAC issues can save money and reduce the maintenance required, but knowing where to start can be complicated. Below are outlined these 7 Common HVAC Issues and what might be causing them.

1. Odours

When a HVAC system suddenly delivers strange smells, this can be due to unclean filters or mould. Running the air conditioner causes condensation to build and if it doesn’t drain out of the unit, mould and mildew can occur. This can cause unpleasant musty smells. Unclean filters can also clog up the system and blow dust and other particles into the air, creating an odour.

2. Inexplicable increase in power bills

Poor maintenance and clogged filters can cause the HVAC system to work harder than necessary in order to cool the space. This inefficiency can cause a dramatic rise in electricity usage, reflected in an increase in power bills. To avoid this, HVAC systems should be monitored and the filters should be replaced quarterly.

3. Inconsistent heating and cooling

Often overlooked when HVAC issues arise, the thermostat can be a common cause of inconsistent heating and cooling in the space. When the thermostat is malfunctioning or in need of repair, it can cause inconsistent temperatures throughout each room, causing some rooms to be warm, while others are cool.

4. Odd noises

If a HVAC system is making irregular or unexpected noises, the reasons could range from mild to serious. A humming sound is often seen as the least serious issue, while vibrations can mean piping or other parts have come loose, which can often lead to expensive repairs. A rattling sound can mean that something has gotten into the system, either inside or outside.

5. System failure or inadequacy

Leaking refrigerant can cause your HVAC system to function poorly, or even not function at all. The refrigerant is required by the condenser unit inside the air conditioner in order for it to properly and efficiently cool. If refrigerant leaks from your system, this may cause the condenser to overwork, resulting in costly issues and even system failure.

6. Reduced airflow

A reduction in airflow can be caused by something as simple as dirty fans. Blower fans shift the air around the ducts. If the blower motor is slow or the fan is dirty, airflow can be hindered and cause less airflow throughout the space.

7. Air conditioner won’t turn off

A common issue with HVAC systems is the inability to switch off the air conditioner. This can be caused by a contactor that needs to be replaced. The contactor is the go-between the air conditioner and the thermostat. When it’s faulty, but the thermostat is in working order, the air conditioner may not turn off. A simple way to be sure is to switch off the power to the property and see if this is the only way that the air conditioner will turn off.

Though HVAC systems can cause problems, they are typically a low maintenance system that adds value to a home. With appropriate maintenance of the system, regular replacement of parts and servicing by a professional, the HVAC system can run continuously and efficiently. If serious problems arise, it is best to consult with a professional.

The above hvac maintenance insights are proudly shared by the hvac experts from

A post by Kidal D. (6134 Posts)

Kidal D. is author at LeraBlog. The author's views are entirely their own and may not reflect the views and opinions of LeraBlog staff.

One Comment

  1. Excellent article. Can be much more reasons for the problems with HVAC system. Since the system consists of: ventilation system, air conditioning and heating system. These systems have their own “special” problems in their correct work. For ventilation and air conditioning system, the main problem is a dirty filter. Then the quality of air purification is significantly reduced. For heating systems, there are two main problems: 1. Pipes. They can flow. 2. Water heater. It can work in the wrong mode, or have technical problems. Therefore, the diagnosis of problems is best entrusted to professional engineering companies.

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