Boilers, furnaces, and water heaters need adequate fresh air to function properly. Here's how to prevent problems.

Try breathing through a soda straw. It takes effort, and you'll probably get dizzy soon. A fuel-burning boiler, furnace, or water heater can also end up gasping for air when installed in a very tight house or a confined space. The appliance won't get dizzy, but it can't burn its fuel properly -- resulting in reduced efficiency, and possibly...

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