How to replace AC grille filter?

DIYHomeAU

Hi everyone,

I’m looking for some advice regarding my ducted AC return air grille (Smartgrille type).

I’ve attached photos of the grille and measurements. The size is approximately 495 mm x 365 mm, which doesn’t seem to match standard sizes I can find at Bunnings.

I have a few questions:

• What size filter should I be looking for (or closest standard size)?
• Does Bunnings stock anything suitable, or provide cut-to-size filter sheet with a frame?
• Do I need to buy the filter with a frame, or is just the filter material enough for this type of grille?

Also, I wanted to check — do I actually need a filter here?

I contacted my builder (Henley), and they mentioned a filter is not required, which is why it wasn’t installed. However, I’ve seen other Henley homes (including a friend’s) where a filter is installed in the same type of grille.

So I’m a bit confused:

• Is a filter optional or recommended?
• Are there pros/cons of running without one?

Any advice or product recommendations would be really appreciated.

Thanks in advance!

MitchellMc

Hi @DIYHomeAU,

It’s generally recommended to install at least a mesh filter in your return air grille. While the system will operate without one, running without a filter allows dust and debris to enter the ductwork and build up on internal components like the fan and coil, which can reduce efficiency, increase running costs, and shorten the system’s lifespan. A filter helps keep the system clean and improves indoor air quality, so it’s a worthwhile addition. However, the best source of information would be from the Ducted AC manufacturer.

We have the https://www.bunnings.com.au/stahl-carbon-infused-ducted-air-conditioner-replacement-filter-mat_p0391475 that can be trimmed to fit, which is the easiest and most practical solution. However, any frame to hold it in position would be proprietary and something you'd need to get from the vent manufacturer. Alternatively, you could consider replacing the whole vent for something like the https://www.bunnings.com.au/accord-600-x-400mm-louvered-return-air-filter-grille_p0182005 , that comes with a mesh filter.

Please let me know if you have any questions.

Mitchell