Are you suggesting that the general atmospheric co2 will be so high air will be unbreathable?
They can rise high enough that general indoor levels (which are usually higher) will be high enough to cause constant cognition problems
Modern building techniques and energy efficient designs can ensure that anyway. Regardless of external co2 levels.
Civilization will collapse first, so no.
It doesn't really matter if it's in your house or not; the problem is global warming that's caused by the greenhouse effect that's caused by the CO2 in the upper atmostphere. I like the cut of your gib though.
Indoor CO2 scrubbers (even just to separate CO2 from inside air and exhaust it outside) would be a great technology right now, since it would allow us to reduce ventilation requirements and thus save on heating/cooling costs.