Furnaces, Air Handlers, & Heat Strips
Let's start with efficiency ratings. Twenty to thirty years ago, furnaces were about 65% efficient. What this means is that 65 cents of every dollar you spent for gas actually went to heat the home, the remainder literally went up the flue. Today's basic units a better - 80% efficiency is what the government requires currently. Again, this means 80 cents of every dollar spent for gas actually goes to heat the home, twenty cents goes up the flue. The furnace which provides the highest efficiency rating is a three stage, variable speed furnace which provides 95% efficiency in most situations. A two stage furnace (which is also available with an 80% furnace) is a furnace which runs on a lower BTU (British thermal unit) level unless conditions call for the highest BTUs available (when it's colder - the unit works harder to keep you comfortable). Variable speed means the unit has a variable speed blower. The blower can adjust itself to the amount of CFMs (cubic feet per minute) that are needed to maintain airflow requirements - it's like a dimmer switch on your lights. Variable speed increases your comfort and can produce an additional 1% - 2% energy savings. Running a variable speed blower takes about the same amount of energy as running a 60 watt light bulb. There are many combinations of efficiency, stages and speeds for consumers to choose from - a lot like choosing the options on a car.
An air handler is the indoor coil and blower for an all electric application. Heat strips are installed in air handler to create the resistant heat. An air handler can also be used without heat strips for cooling only applications (with a boiler for example).
To research individual models, features and combinations, please visit www.americanstandardair.com,