When you burn natural gas, a chemical process occurs and exhaust gases form. These gases include carbon monoxide, which can be deadly if you breathe it in. Thus, when you heat your home with a furnace, you need a good way to vent the gases out of your house. The tricky thing about these gases is that due to combusting fuel, they are superheated. Thus, a furnace not only needs to vent the gases out of your home, but it needs to harness the heat in the exhaust. Your furnace's efficiency will have a lot to do with the machinery your furnace uses to extract the heat from the exhaust gases.
Introducing the Heat Exchanger
A conventional furnace will use a piece of metal with holes bored through it to channel exhaust gases toward a vent pipe. As the superheated gases travel through the inside of the heat exchanger, they warm the metal. Your fan's blower then pushes air over the outside of the heat exchanger. As the air passes over the exchanger, the air absorbs some of the heat from the exchanger. What heat is left in the gases will then travel up the vent pipe and out of your house. This system protects you from the dangerous gases, but it leaves some heat left in the gases, which decreases your furnace's efficiency.
Introducing the Heat Exchanger 2.0
The conventional furnace is an outdated design. Newer furnaces will have a second heat exchanger. This second heat exchanger will extract so much heat from the gases that they will cool to the point that they condense back to a liquid. This second heat exchanger should be made from stainless steel so it won't react with the gases when they convert to a liquid. Your furnace will also need a drain pipe, which it can use to channel the exhaust liquid out of your furnace. You will need a drain somewhere close to your furnace to make this work, but if you can make the drain work, you will get much improved efficiency.
Heating a home through the winter can be quite expensive. You should take any opportunity you have to get your bills lower. Installing a condensing furnace represents a significant cost. While you might be loathe to take on the prospect of financing a new furnace, the savings your furnace will help you realize just might cover the cost of the new furnace and still save you money. Talking with a furnace installer, like Kohl Heating & Air Conditioning, will help you get a better idea of how much money you can save.