The AFUE (Annual Fuel Utilization Efficiency) is a unit that determines the percentage of fuel turned into heat, and the amount of gas that has been exhausted. Appliances like furnaces, boilers, and water heaters are measured on their efficiency with the help of this unit. Most gas furnaces of modern times usually have a rating of 90 - 95% AFUE. This means that 90 - 95% of the fuel is utilized to maintain a warm room temperature, while 5 - 10% turns out as the exhausted portion of the gas.
Therefore, the efficiency of the furnace increases with increasing AFUE, resulting in maximum benefit with minimal loss. Note that according to state law, the least permissible AFUE rating for a gas furnace must be 78%, while the maximum is kept as 97%. The AFUE rating is an important factor that must be unfailingly considered when consumers decide to invest on a gas furnace.
Advantages of Using Gas Furnaces with High Efficiency Rating
# These furnaces make use of electronic ignition technology, unlike the standard forced air furnace, which uses a pilot light. The pilot light is one of the main reasons of fuel wastage, which results in the low AFUE rating in standard furnaces. This is because the pilot light is in a mode of continuous burning, irrespective of whether the furnace is being used or not. The electronic spark ignition, or the 'hot surface', on the other hand saves energy, as it gets activated only when the furnace is engaged.
# Significantly efficient gas furnaces fall in the category of condensing furnaces. They make use of an additional heat exchanger that extracts any heat from the exhausted gases, and condenses it into water. The remaining exhausted gases escape from your home as cool air, due to the condensing surface. This process of cooling off the exhausted gas saves the cost of installing a heat resistant flue. The cool air can be vented through a plastic pipe. The air-borne pollutants released in the process are also reduced. Unlike the traditional furnaces, high efficiency furnaces do not require a chimney.
# These furnaces are built with automatic vent dampers. When the burners are not in use, or they are off, these dampers restrict unnecessary use of fuel by closing the fuel pipe. The improved thermal efficiency is due to the pulse combustion technology, which is a major contributing factor in making today's gas furnaces score high on the AFUE rating. Pulse combustion is basically a periodic combustion of fuel in gaseous, liquid or solid form. And the best feature of this process is that it is self-activated.
# Induced, and regulated amount of air flowing through the system improves efficiency. The regulation of the air also provides a safe combustion.
Top Gas Furnaces on the Market
- American Standard Platinum ZV Furnace
- AS Freedom 95
- Bryant Evolution 96 Gas Furnace
- Carrier Infinity 96 Gas Furnace
- Heil VC97 QuietComfort Furnace
- Lennox SLP98V Variable-Capacity Gas Furnace
- Trane VX Gas Furnace
- Trane XL 2-Stage Furnace
High efficiency gas furnaces, undeniably, cost more than the traditional ones, given their features like variable air blowers and variable heat outputs, to name a few. Having said that, it is understandable that the higher AFUE an appliance has, the more expensive it will be.
But you can consider it as a profitable investment if your house is in a constant need of warm air, and especially when you are looking forward to a lifetime usage of the furnace. And for the same reason, it is necessary that you go for products with long warranty period, and those that suit your house needs. To add, the savings that you can make with their use, will definitely be worth the sum you have spent initially.