One of the fastest ways to improve the air quality of the home is to remove combustion from the house. The burning of fossil fuels is unnecessary, costly, bad for your family, and bad for the environment. In the Bay Area, heating and cooling needs are typically milder than in other climates with bigger seasonality shifts. With a tight building envelope, those needs are reduced even more. This solution could be as simple as a mini-split and electric stove, or as unique as a geothermal floor, radiant heating, or whole-home hydronics.