Gas Furnace Efficiency

Technology is constantly evolving to create more efficient heating systems that can reduce emissions and derive more energy from fuels. If you have a gas furnace heating system that is more than 15 to 20 years old, you might want to consider going for a replacement soon. Modern gas furnaces are much more efficient compared to the older ones.

Investing in a new gas furnace is well worth it, considering the money it will save you in the form of lower fuel bills in the future. So, if you have made up your mind on choosing a new gas furnace, you need to know how to determine gas furnace efficiency. After all, efficiency is the most important factor when purchasing any machine ranging from a car to any household appliance like the water heater. In this Buzzle article, I will show you how to determine the efficiency of a gas furnace, by studying its specifications.

How Do Gas Furnaces Work?

Before we talk about the efficiency of a furnace, it would be instructive to know how gas furnaces work. A gas furnace draws in air from inside the house and separates all dust and large particulate contaminants using air filters. This filtered air is then passed through a heat exchanger, powered by natural gas combustion and then this warm air is circulated through vents, back in the house.

The emissions created due to natural gas combustion are removed through special vents and directed out of the house. Modern high efficiency furnaces are designed to utilize the heat that is contained within these exhaust gases too, which makes it possible to substantially enhance efficiency.

How to Determine Gas Furnace Efficiency?

Knowing the efficiency of a gas furnace is extremely simple. Every gas furnace manufacturer must specify the AFUE (Annual Fuel Utilization Efficiency) rating, quoted in percentage. By knowing the AFUE percentage rating of gas furnaces, you can compare them to choose one with high efficiency.

Old gas furnaces from the 1960s and 1970s have an AFUE rating ranging from 65% to 75%, while modern furnaces can provide an efficiency rating of more than 90%. If you do the math, a 15% to 20% enhancement of efficiency translates into a saving of thousands of dollars in heating costs over a year. So, it makes abundant sense that you go for a gas furnace with enhanced efficiency.

High efficiency gas furnace prices are substantially higher than furnaces, that have lower than 80% AFUE rating. Of course, you need to consider the economics of buying a new high efficiency gas furnace, before you purchase one. It makes sense to go for a system with high efficiency, in cold climates, where it's frequently used.

That way, you can recover the investment made in these expensive furnaces over a short period of time. If you live in temperate climate, it doesn't make economical sense to go for a high efficiency furnace, with its high cost, when you are going to use the system for a very limited time, over the course of a year.

All you have to do is check the annual fuel-utilization-efficiency (AFUE) rating percentage, when choosing a gas furnace. More the efficiency, higher is the furnace cost. However, you can recover the extra cost in the long term, as the high efficiency brings down your spending on energy bills. Paying more now for a high efficiency furnace, rather than settling for a low efficiency furnace which is going to cost you more in the long term, makes sense.