Air handlers and furnaces aren't typically used side by side in Kitchener. If you use a furnace, you likely won’t need to consider an air handler.
Air handlers are typically used with heat pumps and manage airflow across your house. Some units also provide extra heating and cooling pieces to support the heat pump.
A furnace works in a different manner by blowing heated air into your vents, which send it around your house. As furnaces use combustion chambers to produce hot air, they don't need some of the parts you'll see in a standard air handler.