When they say a lot of them, they mean, a LOT: "Realistically, you would need hundreds of plants in any one room in your home to compensate the CO2 emissions from just one person."
Because that would require a lot of plants.
A human exhales about 2.3kg CO2 per day. So that's 12/(12+216)2.3kg or 630g of carbon. A plant maybe absorbs 1g a day? Lets say a bit more... You probably need somewhere in the range of 500 indoor plants.
And I am to remember that they only absorb CO2 when photosythesising. When it is dark they are still respiring and producing CO2 with the humans
a number I found quickly says a greenhouse full of crops consumes 0.12-0.24 kg CO2 per hour per 100m²
I don't think those numbers are applicable to house plants. Crops grown in a greenhouse are specifically grown to increase their mass in as short a time period as possible. Regular house plants usually don't increase their mass that much (you don't really want them to), they don't get nearly as much energy and nutrient input as greenhouse crops.
I thought "you'd need a large apartment worth of plants per person" was bad enough already, without caveating it on plant type
only during daytime. At night they also dump out CO2.
Plus you need a lot.
you’ll probably need a lot of them. or actual trees.
Algeae. Bubble your exhaust through some water, gain back some of your heat too. Maybe produce Hydrogen on the side. You could feed animals with the excess algaea.