minimum oxygen concentration for combustion

Doctomology is 395 pages of simple knowledge. Most people are paying anywhere from $27-$197 dollars for a similar books, with the same information. The Marketers that are selling you these books are crooks. They thrive on peoples dreams of becoming rich. This in my opinion is very unscrupulous of them, and should not aloud. Please go to my site or other site you'll find this book everywhere, and download it for free. My gift to my fellow Marketers beginning. A tighter built home means less outside air infiltrating in the home, which means less oxygen to use for combustion within the furnace. As the furnace burns fuel and oxygen for combustion, it "eats up" surrounding air, which has to be "made up" with fresh air. If air cannot type in the home as easily anymore, this can cause serious issues. As the surrounding air is utilized for combustion, rather than substituted with oxygen, a negative pressure inside the space can happen. This could create combustion problems for the furnace, plus burn up fresh air for anybody inside the home.