Is that true that the smoke will get in after a few hours? Over the last few days, as soon as I step outside, I can smell the smoke out there really bad. I thought for sure that if it was smokey in the house, my nose would be used to the smell. I mean, I can see some particles getting into the house, but it has to be far better indoors doesn't it?
Certainly yes, it's better indoors. However long it'll take will depend on how good your insulation is (a lot of older construction in the Bay Area has really poor insulation; after all, we don't have to deal with harsh winters). That said, when it gets really bad outside (AQI >150) for over a few days, it's almost certainly going to get bad inside if you don't have any filtration.
One thing worth mentioning though is that the smoke you smell is volatile organic compounds, and the smoke you see is (I believe) PM10. You're not going to smell or see PM2.5, which is what these HEPA air purifiers are designed to filter. I'm not confident in this, but my intuition is that these smaller PM2.5 particles will find their way into your home more more quickly than the larger PM10 particles will.
