> Those 2-in-1 filters do exist but cost more. And many are scams because they don't have enough volume of activated carbon.
Any filter with a little bit of carbon added is going to be useless after a few days, or maybe even hours.
The only VOC filters that work have multiple pounds of carbon, with the good filters having upwards of 10-20 pounds. It also has to be replaced regularly.
You can safely put a washer and dryer on the upper floor of a house if you add a proper floor drain, but you’re unlikely to see anyone add a floor drain in new construction because buyers aren’t looking for it. Now multiply that by everything a buyer isn’t looking for and you’re talking real money.
European here, we've always been placing washer/dryer stacks in our bathrooms without needing floor drains. We have machines with a system called Aquastop [1] that stop the water flow if the machine detects a leak inside the system.
The real activated carbon filters have 10s of pounds of carbon. The little black foam thing that comes with those 2-in-1 carbon filters is useless.