HVAC Troubleshooting: Why is My AC Rattling?

Posted on: August 8, 2016

When you hear your AC rattling, it is a good indicator that something has gone awry with your HVAC system. Ignoring the issue will create expensive repairs, so make sure you schedule a maintenance, tune up, or repair appointment with a licensed HVAC contractor. There are several situations that could cause a rattling noise – it could be an easy fix such as tightening screws, or it can be an indicator of malfunctioning parts which can become very expensive if gone unrepaired.

Debris

When the filter has not been changed for a while and becomes clogged, dirt, sticks, leaves, gravel and other types of debris can enter the AC cabinet and get knocked around. A dirty AC filter can cause serious damage to the AC’s parts/components along with a variety of other issues, and should be fixed immediately to prevent any more debris from entering.

Panels

Poor installation or aged AC parts can cause screws to become loose, which cause the panels on the cabinet to unfasten. This is common with old HVAC systems, which should be maintained at least twice a year.

Fan

Rattling caused by the fan within the AC unit could be from the blades themselves can becoming loose, especially in older AC models. Luckily, fan blades are easily replaceable. If the fan is misaligned due to debris or age, it will progressively get worse and eventually cause the fan to stop functioning. Dirty blades can also cause noise, so it is important to keep the blades clean and make sure your AC filter is changed regularly.

Motor

The compressor is the ‘heart’ of HVAC system, and when its parts become loose it can cause a total system breakdown. This is more common with older HVAC systems. When the noise increases from the compressor, it is usually a strong sign the compressor’s hardware needs replacing.

Installation

An unstable AC unit is a common source of rattling noise. Improper installation can cause parts to be more susceptible to damage. The noise could be from the damaged parts or by the AC unit or the platform not lining up with a window sill. Re-installation can easily fix the rattling if you notice loose/shifty parts.

Preventative maintenance can fend off unwanted repair bills and inconvenient HVAC malfunctioning during the months you use it the most. Call us today to learn more about our Precision Tune Up Program or to schedule an appointment for repair with one of our NATE-certified technicians!