The most efficient furnace that is on the market today is not confined to a single brand. There are a number of manufacturers that have natural gas furnaces that exceed 95%. 95.5% to 96% are the top numbers in the field. The difference in efficiency is negligible. It is the difference in installation and maintenance that really brings the efficiency to where it needs to be.
Using a process developed by the National Comfort Institute called HeatMaxx we have tested a great many gas furnace installation here in Southern California. We are currently averaging an efficiency for these forced air heating systems right around 67%. This means that if you install a 96% AFUE furnace that is 100,000 btus of gas input and it is operating at 67% efficient you have an effective efficiency of (0.96 x 0.67 = 0.6432) 64.32%.
The reason is very clear and it has very little to do with the furnace manufacturer. Sure, some of the gas valves are set wrong from the factory. Sure, sometimes the blower speeds are set wrong. Sure, sometimes the factory perfect condition testing doesn’t match up to reality. But, the real problem is that only one part of the system was replaced or fixed.
And would you expect it to perform like a Ferrari? That is exactly what is typically happening. Much of the ducting hat we see has no insulation on it or as little R2. The joints are leaking and the ducting is nearly always undersized. The air leaving the bonnet of the furnace is a very warm 130 degrees, but the time it reaches the interior of the home on the last duct run the air temperature is closer to 100 degrees. Upwards of 1/3 of the heating ability of the furnace is lost through poor ducting design, poor ducting installation, leaks in the joints and connections and heat loss through inadequate insulation. This is normal!
We just have to find out where they are. Give us a call and we will come to you and perform a full system HeatMaxx evaluation and show you where the problems with your system are and what you can do to fix those problems.