Although Chicago is known as the Windy City, it is in fact less windy than many other major American cities. Average wind speeds range from 8 miles per hour (13 km/h) in late summer to 12 miles per hour (19 km/h) in spring months.
A flue is a duct, pipe, or opening in a chimney for conveying exhaust gases from a fireplace, furnace, water heater, boiler, or generator to the outdoors.
Now, hereâs the difference between standard-efficiency and high-efficiency models. In gas furnaces, there is a component called a heat exchanger. This is where natural or propane gas is converted into heat energy and byproducts produced from the combustion process are vented through the flue system. Well, in a condensing gas furnace, there is more than one heat exchanger. The secondary heat exchanger removes more heat from the combustion gases, which then condense to produce water vapor. Then, cooled flue gas is vented out of the flue system.