Advice please for enhancing air conditioning filtration?...So I don't die from toxic mould.

Forums › Home Workshop DIY › Advice please for enhancing air conditioning filtration?...So I don't die from toxic mould.

kenkeniff

628 posts

Ultimate Geek

#138853 19-Jan-2014 13:54

I've been noticing a lot of dust in the air at my apartment (even after vacuuming regularly) and generally not feeling so well so decided to inspect the air conditioning system;

The air conditioning unit is situated in the roof cavity by our door and sucks up a lot of dusty air through the doorway from the apartment hallway;

Filter removed:

The unit has a 4-layer metal mesh filter with aluminium frame which only catches very large particles and lets most of the dust through into the system:

The air exits two ceiling air diffusers;

I've just finished cleaning the air conditioning fan, filter, air diffusers and toxic-looking mould from the shafts above the diffusers.

I want to install some filters (like a washable HEPA filter) that will actually catch all the dust and cr@p and remove it from the air instead of just blowing it around the place.

What do you think is the best way to go about this?

The metal filter has a bit of room in the frame where I could stuff some filter fabric in to act as another filtering layer however I'm not sure where to get this from.
Unless I can just get a better filter to replace it (measures 225x840x12mm) however also not sure where to get this from.
I also have the option of adding some filters or some sort of filtering fabric to the air diffusers however I'm not sure how any of these option will affect the performance of the air conditioning unit.

RunningMan

8961 posts

Uber Geek

#969647 19-Jan-2014 14:10

I'd replace or supplement the aluminium mesh filter with some sort of HEPA filter, so the supply to the unit is filtered, rather than filtering at the outlets.

Any heat pump supplier that installs ducted units should be able to assist - quite possibly off the shelf if it's a standard size.

The filter in my system is approx the same dimensions and has a sticker from these guys

http://www.safe.co.nz/filters/flat-panel-filters.html

You could try this company - never used them, so don't know what they are like.

http://www.filtercorp.biz/

kenkeniff

628 posts

Ultimate Geek

#969709 19-Jan-2014 17:40

Thanks, I'll give them a go.

I wonder it there's any sort of spray you can get that will stop the mould growing inside the air ducts (and is safe to breath)?

gazbo

89 posts

Master Geek

#969711 19-Jan-2014 17:53

There are mould resistant paints but that would be difficult to apply. The best method is to keep the area dry.

There are over 200 different black moulds found in NZ but only one is toxic (stachybotrys atras). And that needs a relative humidity of close to 90% to initiate growth but only 70% to sustain it once initiated. It also consumes cellulose so needs wood fibre based products like gib to survive so is unlikely to be in your vents.

kenkeniff

628 posts

Ultimate Geek

#969712 19-Jan-2014 17:58

gazbo: There are mould resistant paints but that would be difficult to apply. The best method is to keep the area dry.

There are over 200 different black moulds found in NZ but only one is toxic (stachybotrys atras). And that needs a relative humidity of close to 90% to initiate growth but only 70% to sustain it once initiated. It also consumes cellulose so needs wood fibre based products like gib to survive so is unlikely to be in your vents.

We have the air conditioning on cold 24/7 (as the building maintains incredibly hot hallways which heats up all the rooms) so the ducts do seem to be constantly exposed to condensation however ironically the rest of the apartment seems very dry.

The black lining you see in the last photo is some sort of fibre-sponge so not sure if it can be painted. I was thinking of 'Exit Mould' or something like that but not sure if that would be smart to put in the air system.

RunningMan

8961 posts

Uber Geek

#969720 19-Jan-2014 18:53

I would have expected the condensation to form inside the unit when on cooling, and drip out through the drain. There isn't a blocked drain or similar which is keeping the condensation inside perhaps?

kenkeniff

628 posts

Ultimate Geek

#969730 19-Jan-2014 19:31

RunningMan: I would have expected the condensation to form inside the unit when on cooling, and drip out through the drain. There isn't a blocked drain or similar which is keeping the condensation inside perhaps?

Possibly, but condensation also forms on the air diffusers, presumably because they are colder than the surrounding air.

kenkeniff

628 posts

Ultimate Geek

#969892 20-Jan-2014 10:04

RunningMan: I'd replace or supplement the aluminium mesh filter with some sort of HEPA filter, so the supply to the unit is filtered, rather than filtering at the outlets.

Any heat pump supplier that installs ducted units should be able to assist - quite possibly off the shelf if it's a standard size.

The filter in my system is approx the same dimensions and has a sticker from these guys

http://www.safe.co.nz/filters/flat-panel-filters.html

You could try this company - never used them, so don't know what they are like.

http://www.filtercorp.biz/

Just spoke to Safe.co.nz who will make up a custom washable filter for <$40 which is pretty good. Cheers

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BTR

1527 posts

Uber Geek

#969908 20-Jan-2014 10:49

Do you own your apartment or are you renting? If renting call you landlord to sort it out.

kenkeniff

628 posts

Ultimate Geek

#969912 20-Jan-2014 10:55

BTR: Do you own your apartment or are you renting? If renting call you landlord to sort it out.

Renting in a Hotel. They do service the filters every now and then however they choose to use these types of filters so they don't have to do it too often (as they don't catch much dust).

I don't think I'll have much luck from the landlord so don't mind paying $40 for a healthy set of lungs considering I work from home a lot.