I have been trying to find some help with a residential air exchange/ventilation system for our home for some time now, figured perhaps someone here on GBA might be able to steer me in the right direction, or at least help me figure out a few specs if I end up having to do this myself as a homeowner, without any background in construction or engineering whatsoever.

Residence is approximately 2200 sq ft, climate 3B on the map, Los Angeles County. Newly constructed in 2016, purchased after completion. The plan was to make this place as green as possible before moving in, but I had no idea how bad the offgassing would be. Unfortunately, the majority of the home consists of high VOC and formaldehyde-containing materials, most of which I am trying to now remove/replace or seal as practically as possible. Removed all the formaldehyde insulation in the attic and have been running commercial sized HEPA/charcoal filtered scrubbers for over a month now. Formaldehyde levels alone came down 50% since these efforts and general offgassing, however, the levels are still too high for the IAQ to be healthy or habitable for someone sensitive like myself.
Based on the TO-15 testing, I was able to identify that another major culprit for the poor IAQ is the existing interior paint and cabinetry. The solution I found online to deal with the cabinets is to seal them with the AFM safecoat polyureaseal BP, as I’m told that will greatly reduce the offgassing of formaldehyde and VOCs. And as for the interior paint on the walls (turned out to be a high VOC Glidden formula), I figured I could have all the existing paint sanded off, while everything that isn’t wall is covered with some poly and plan on keeping the HEPA/Charcoal scrubbers exhausting under negative containment simultaneously. Since the materials and paint all came back negative for lead and asbestos (I did these tests as a precaution, as a previous 2010 remodel of a newly tiled shower surprisingly came back afterwards as positive for lead at our last home), I am unaware of any harm in sanding down to the drywall or down to the orange peel or rough -whatever that textured layer is called between the paint and drywall itself. Maybe even wet-sand it off if VOC release during sanding is a major concern? Then, after the paint is sanded off, AFM new wallboard formula and primer/paint could replace it, as I’m told their Hard Seal is in there somewhere too and that these products are zero VOC. I figure this way I won’t be adding anything toxic, and that the hard seal in there will at least prevent offgassing of anything missed or left behind. I’ve only gotten as far as the idea, as I have yet to discuss this with anyone knowledgeable in VOC removal or VOC paint removal techniques. The abatement contractor I’d used before said he is willing to do the sanding and painting for me if I can tell him exactly what to do, since it really sounds the same to him as removing lead-containing paint, but I want to be sure I’m barking up the right tree with this approach first. The alternative was to seal the walls with just AFM safecoat hard seal( over the existing VOC paint) or just the transitional primer (that has the hard seal in it too) but I do not want to worry about VOCs on my walls ever again if avoidable.

And this all brings me to the ventilation system…the paint, the cabinets, and the insulation seem easy enough to remedy. The very stinkly laminate flooring I’ve yet to figure out, might remove and polish the concrete slab below if I have to. But the reality is that everything else in the house that cannot be removed practically or sealed will continue to offgas and leaving the windows open all the time is simply not practical either (nor will it be greatly effective, based on what I’ve been reading).
I’ve read every single article on GBA in the ‘how to do everything’ Ventilation section, and after supplementing that reading with some additional online research, I feel pretty confident that I need a balanced system with an ERV and dedicated ducts. Possibly a dehumidifier if I find I need it, but that can be sorted out later as it need not be a part of the actual Ventilation system.. Now that I’ve tried running the existing exhaust fans in the house continuously, I realize there just isn’t much fresh air coming in and the continued off-gassing I cannot avoid remains a concern. I have consulted an OSHPD inspector, who agreed that the IAQ levels are not healthy for anyone, let alone someone with sensitivities, and have since been trying to find anyone with the expertise to help me figure out how to plan and put this together. Most HVAC companies have told me they aren’t experienced with these systems (even some that sell ERV/HRV units), and the few companies that were knowledgeable said they only take on higher-value projects like colleges, hospitals, etc. (not residential). And, again, my own abatement contractor offered to help if I couldn’t find anyone, but his own HVAC contractor said they have never done anything like this before and would need a third party engineer or someone with extensive experience to fill the knowledge gap if they were to try. The permit application requires an engineer anyway to sign off on the system prior to the permit being issued, and I haven’t managed to find anyone in Southern California willing or able to take this on that services the LA area in California. So, any suggestions on where I might need to look next? Or is this something my contractor and I could try to DIY without causing problems? My gut says the answer to the latter is a big ‘no’ but if I can’t find someone to help with this, I’ll have to figure something out. Cannot move in until I can breathe in there without becoming ill. Appreciate any advice and thank you for taking the time to read this.