Gas furnace systems are gradually becoming the preferred way to heat houses the world over. There are multiple causes for this and all of them are fairly evident. Gas furnaces provide a level of convenience and comfort that has made them this much popular along with the fact that the standard of living and purchasing power of humans across the world is consistently improving. These heating systems run without a lot of maintenance and work when compared against earlier versions of furnaces or even fireplaces. Furthermore, these systems are more efficient in terms of heating and fuel efficiency, even though cost volatility of natural gas is a hindrance. There are a variety of gas furnaces that are available to a consumer. There are two ways in which gas furnaces can be categorized; one is on the basis of their working and the other is based on their efficiency. The following is a list of most common types of gas furnace systems and their features.

1) On The Basis Of Their Functioning:

a. Central heating systems:

Gas furnace systems of this type distribute warm air to the whole house. This gas furnace can be divided into two parts, i.e., the first part which does the heating and the second part which undertakes the heat distribution process. The level of heating can be managed in this system through a thermostat that is installed along with a fan that does the distribution.

b. Forced air:

This is the most common type of gas furnace system that is found in the world today. This type of gas furnace is considered to be relatively more fuel efficient than the earlier one. The main concept behind this system is that the air inside the house is pulled in by the machine and heated to be redistributed in the house forcibly. In some cases, these systems also pull in air from outside the house which keeps the air in the house from getting stale and allows ventilation.

c. Condensing furnace:

This is considered to be the most efficient type of gas furnace system. These furnaces come equipped with condensers which prevent excessive heat loss from exhausts. The heat is gradually trapped from the exhaust and reused.

2) On The Basis Of Efficiency:

a. Standard efficiency:

These are no longer produced commercially but can still be found functioning in some small commercial buildings and homes. The fuel efficiency of these systems is around 50 to 79 percent. These use a single heat exchanger.

b. Mid efficiency:

These types of systems are in reality just a modification of the standard efficiency systems and hence provide just a little amount of improvement in terms of efficiency. Their fuel efficiency on an average is between 80 and 85 percent. Similar to standard efficiency systems, these also use a single heat exchanger.

c. High efficiency:

These are extremely efficient gas furnace systems that have been recommended by governments and environment based organizations all over the world. Their fuel efficiency is around 90 to 97 percent. The extra fuel efficiency is obtained due to the inclusion of a second heat exchanger that can recover around 10 to 17 percent of the heat produced.