Furnaces did not change their basic design for years, a design which is modeled after how a stove works: you burn a fuel, and the smoke created by burning the fuel escapes your house through a vent pipe after providing some heat to your home. A furnace differs from a stove in that it uses a heat exchanger to extract heat from the exhaust created by combustion. A condensing furnace differs from this typical design in that it doesn't vent exhaust out of your house through a vent pipe, and there is a good reason for this.
The Problem with Venting Exhaust out of Your House
When you burn a fuel, a lot of the heat thus created resides in the exhaust. The heat exchanger in a conventional furnace absorbs some heat from the exhaust gases. The fan in your furnace then pushes the air inside your home over your exchanger, which both cools the exchanger as it warms the air flowing over your furnace. The problem with the conventional design is that it leaves some heat in the exhaust gases. You still have to pay for the fuel to create the heat, but it vents out of your home. A conventional mid-efficiency furnace will not achieve better than 83% efficiency and can have an efficiency as low as the fifties. In other words, at best you are throwing away $15 for every $100 you spend.
Isn't Exhaust Toxic?
The exhaust created by burning fuel can be toxic. Thus, you can't have it filling up your house. A condensing furnace still creates exhaust, but it has a second heat exchanger. This allows the furnace to absorb so much heat from the exhaust gases that the exhaust converts back to a liquid. This liquid exhaust can then be drained out of your furnace through a tube dedicated for that specific purpose. If you pair two heat exchangers with a modulating motor, you can achieve an efficiency rating of up to 98%. Remember that a conventional heating system will have a furnace connected to a duct system. To get a 98% efficient system, you need a 98% efficient condensing furnace. The furnace is the key component in the system that allows you to save a lot of money over the life of your system.
A condensing furnace will cost more to install than a conventional furnace. Most homeowners will have no choice but to finance no matter which furnace they choose. As long as your financing costs do not total more than the amount of money you stand to save on your heating costs, you should save more money in the long run with a condensing furnace. If you decide that a condensing furnace is worth the money, contact a company like Bill's Heating & Air Conditioning to have one installed today.