AC in very unhealthy air quality area

June 29, 2023 3:11 AM

We are in a very smoky area, and people in my household have respiratory ailments. What if anything can we do to help maximize better indoor air through our central air conditioning?
posted by ojocaliente to Home & Garden (8 answers total)

Set the fan to continuous operation and replace the filter more often? That’s really about it.
posted by Thorzdad at 3:41 AM on June 29, 2023 [3 favorites]

Get the best filters that your system will support. MERV 13 if possible.
posted by rockindata at 3:56 AM on June 29, 2023 [8 favorites]

You could leave the A/C as-is, and build one of these
posted by superelastic at 4:08 AM on June 29, 2023 [6 favorites]

nthing to change your HVAC filter if you haven't recently, and upgrade to the best it'll support.
posted by chiefthe at 4:32 AM on June 29, 2023

You may burn your HVAC system out if it is older and you put too-dense high-end filters in it. This is a decent write-up on what filters can and can't do and what your system is probably meant to run on. In Los Angeles we kept a hoard of extremely cheap filters to use during wildfires, changing them every day or two. We also ran a humidifier near the indoor air return vents to make the dust stickier, but we were dealing with very low humidity. I think if I ran one here in Wisconsin it'd make water drip off the ceilings.

They do make a sort of spongelike pre-filter material you can put in your air return vents. I think they have to be too porous to really help here - it can be good for protecting the internal systems from large objects like pet hair. You definitely run the risk of over-blocking airflow and damaging the equipment.

Building a filter box with a fan, if that's something you can swing, will help. We also did that in LA, though today I am sitting huddled up to the room-sized air purifier I just unboxed because it was smaller and easier. If you run any kind of air filter, you can either run it near the people or near the air returns so that you are pre-cleaning the air going through the ventilation system.
posted by Lyn Never at 5:34 AM on June 29, 2023 [5 favorites]

Buy an air purifier if you can find one.
posted by theora55 at 9:32 AM on June 29, 2023 [4 favorites]

Unless you are in a modern condo or apartment building, your central AC likely is not designed to draw in any outside air. It recirculates & cools the air already inside the house. So the strategies for good air quality are really the same as a house with no central air - keep doors and windows shut (easier with AC) and run an air filter.

Typically the filter on your AC itself is meant to protect your AC, not clean the air. Too much restriction on the air intake can cause poor performance and reduced lifetime. Modern ACs may be a little different so check the manual for your AC. But a separate HEPA filter does a good job.
posted by muddgirl at 9:45 AM on June 29, 2023 [1 favorite]

Nthing constructing a corsi-rosenthal box or even using one box filter and fan to create a “clean air room”.
posted by sparringnarwhal at 5:22 PM on June 29, 2023