Along with our new Trane xli21L we had the Trane CleanEffects 1200 whole house filter installed. My wife swears that when sunlight is shining through the living room windows, we do not seem to have anywhere near as much floating dust particles visible as before.
Not hardly a scientific measure, but she says she feels better. As for me, I can't feel any difference from our previous heat-pump with 4 inch filter and this filter.
Back in '75-77 we were stationed in Ankara, Turkey (USAF). Due to the extensive use of coal for heating in all the buildings and the fact that the city is like in a bowl, surrounded by mountains, level of pollution during winter is one of the highest in the world. The AF issued us electronic precipitators and they did a pretty good job at filtering large coal particles in the air. We had to wash the filters in running water and you could see the blackish water running out. Whenever it snowed, you could see the coal particles in the snow flakes. Must of the time the snow flakes where grayish, instead of pure white.
Nice place during summer, but glad we got out of there without any serious respiratory problems, after being there for two whole years.
I just finished a job last week sealing the return air chase, ducts at plenum and supply boxes at floors.
Homeowner's complaint of allergies, dust and high RH.
She left me a message on my house phone today that the RH was lower, hadn't dusted but once since I left and that the filter was actually getting dirty.
prior to the sealing of the R/A chase there was a lot of air bypassing the filter.
the wall where R/A grill was installed was open to the attic. gaps between 2x's in corners
of chase, and where R/A plenum was attached to top of chase there was a 1/2 tp 3/4"
supply boxes picked up off attic floor, ducts not mastic sealed to plenum.
this may not be your situation, but I always look at infiltration, return and duct leakage
when trying to clean the air that is conditioned and entering the living space.
oh and they had that damn cellulose...that was her dust issue..only it wasn't dust
but fine particles of cellulose (newspaper treated with borate).
not a big fan of uv lights.
are the ducts and R/A sealed?
what type of insulation??
sorry to hear your family is having this issue, and hope you can
easily resolve it.
The cure of the part should not be attempted without the cure of the whole. ~Plato