Trane Gas Furnace Efficiency FactorsTrane Gas Furnace Efficiency Factors – This is a Trane gas furnace. It is also called a Trane 90 plus gas furnace because it offers efficiency levels up to 90 percent plus AFUE (rating). Gas or oil furnaces generally cannot achieve efficiency at 100% because of impurities in the fuel including moisture. This is the reason why no fossil fuel furnace sold has a rating of up to 100%.

This biggest impurity in many fuels is moisture which is difficult to remove because it is in the distribution and storage places where the fuel is distributed and stored. If these impurities were removed from the fuels before they have been introduced to the furnace the cost of the fuel would be much higher and the cost to benefit ratio would not be effective.


Trane Gas Furnace Efficiency Factors – Additional Efficiency Factors

Fuel purity cannot be overcome without costly and excessive filtering that makes the savings factor useless. Whether it is a Trane gas furnace or a Goodman gas furnace this factor cannot be overcome. The fuel you buy from the gas company through a pipeline is what it is. There are other factors you can do to make sure you get the most out of the efficiency of the HVAC system. External factors to the HVAC system refer to your home. The windows and doors. Infiltration and exfiltration factors must be taken into account when looking at efficiency factors is important. Infiltration is outside air coming into the structure.

Exfiltration is the air in your home, making its way out of the structure. That all has to do with insulting factors for the structure. The tighter the house the more efficiency you will save for heating and cooling. Within the HVAC system, there are also efficiency factors not related to the equipment. In this case, it’s a gas furnace or the heating system we are discussing. The external factor from the gas furnace itself is the ductwork.

Trane Gas Furnace Efficiency Factors | Additional Efficiency Considerations

You can have a 90 plus gas furnace and get efficiency, but if your ductwork is bad or your house has is drafty windows and doors with bad insulation in the walls, you will not gain so much as far as efficiency is concerned. Of course, it should be better than the older furnace but to increase efficiency for the whole system take care of other factors in addition to getting the new high efficient furnace. That is a good reason before you have a high-efficiency gas furnace installed that you look at the big picture and have an effective plan in place to fix drafty windows and doors and add insulation to your home or business.

Overall Factors/Evaluation | Trane Gas Furnace Efficiency Factors

It is also a good reason to do a complete evaluation of the entire HVAC system, including the ductwork. Leaking ductwork will cause you to lose the efficiency of the whole system because the conditioned or heated air from the high-efficiency furnace is not being delivered to the room where it is needed. Instead, it is wasted in the space where the ductwork is located. The conditioned air should be delivered into the room and not in the attic or under the house. Give serious consideration to these factors, and you will not regret it, especially when you the gas or electric bill.

Tweaks for Efficiency | Trane Gas Furnace Efficiency Factors

Furnace Efficiency and Ductwork

Ductwork is a part of the HVAC system that delivers the conditioned air throughout the home. The conditioned air is paid for by you through the furnace heating the air. You pay for the gas and the electric heat and move the air. If the ductwork is leaking the conditioned air, you are losing money. It may be in small increments but it’s lost money spent unnecessarily on conditioning the air lost. Over time, that can equate to lots of money that could have otherwise been saved.

Lastly, homeowners are always interested in replacing an old furnace but typically ignore the ductwork. The ductwork is even ignored when recommendations are made to repair it or replace it. The repair can include fixing holes/leaks and reinsulating the ductwork. Additionally, it is important that the ductwork is sized properly. Most HVAC contractors can easily figure out sizing and pressure requirements based on the size of your HVAC equipment. Lastly, why would you spend lots of money on a new high efficient furnace and have bad, leaky ductwork?

Infiltration and Exfiltration and Furnace Efficiency

This goes with insulation in your house and good tight doors and windows. Energy-efficient windows and doors will make your home tighter. Fewer drafts and less heat lost. That equals more comfort for you and puts less of a load on the furnace. Additionally, aside from doors and windows, insulation in the ceiling will help save money on utility bills. Older homes in historic districts need to be checked for insulation in the walls. In some places, insulation was not used in the walls. Insulation can be blown in through a hole and then sealed making your walls more resistant to heat loss and heat gain.

Furnace Efficiency and Humidity

Raising the humidity in your home will make you feel warmer. When you run the gas furnace the air expands. This results in dryer air. Low humidity levels will make you feel colder giving the feeling that you need to raise the set point on the thermostat. A whole-house humidifier can raise the humidity levels in the heated air coming from the furnace. This means you can be just as comfortable with the thermostat setpoint of 68°F over no whole-house humidifier and the thermostat setpoint of 74°F.

Conclusion | Gas Furnace Efficiency Factors

As you can see there is much more to having true energy efficiency and an energy-efficient gas furnace than just buying a top AFUE furnace. Take the extra steps and get superior energy efficiency, save energy and utility costs.


High Performance HVACTrane Gas Furnace Efficiency Factors


95% Plus AFUE Gas Furnace


Low AFUE Furnace


Good Tight/Sealed Duct Work


Bad Leaky Duct Work


Efficient Doors and Windows


Leaky Doors & Windows


Great Efficiency/Comfortable with Low Gas Bill


Cold/Uncomfortable with High Gas Bill

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