#1 Best Gas Furnace Efficiency to Buy in a Hot Climate

What Type of Furnace Efficiency Should I buy for my HVAC System when I live in a warm climate?

Furnaces are the long forgotten child of the HVAC system for home owners in cities like Houston TX.  This is apparent when comparing the fall vs the spring tune up seasons.  During Springtime customers are ~twice as likely to schedule their maintenance than in fall.  Why is this? Isn't the answer obvious?  It is hot'n'herrr.  This difference in behavior probably stems from fear.  The fear of losing A/C in the summer time is far greater than losing your heat in the winter.  Furnaces also last longer than Coils and Condensers in souther states.  This thinking however can cloud your ability to make a proper choice when looking to purchase a new furnace.  In fact, your furnace is INTIMATELY involved with the cooling of your home.  Even more so it is involved with the cooling efficiency of your home.  Extremely important factors to consider.



The basic breakdown of residential furnace choices come from two different elements that effect system efficiency - AFUE and Motor Type (variable, single, modulating etc). 

AFUE is Annual Fuel Utilization Efficiency.  This is a measure of a gas furnace's efficiency in converting fuel to energy.  This is represented by a Percentage.  The higher the AFUE the higher the efficiency.  Put simply, an 80% Gas Furnace converts 80 cents worth of gas fuel purchased directly into heat with 20% 'wasted'.   Typical furnace efficiencies on the market for home owners include 80%, 90% & 95%.  

The 80% AFUE Furnace is the most commonly purchased rating in Southern Climates(USA)

The AFUE does NOT effect the cooling efficiency BUT the type of blower motor in an furnace DOES.  Why? Because the blower motor sends air through your home during both the heating AND the cooling cycle.  Your furnace is the driver of air into your home during all seasons.  Therefore the more efficient the motor the less energy used during the A/C.  Standard motor types include. Single Stage, Two Stage and Variable(modulating). 

Single stage units only have one setting ALL ON or ALL OFF.  Where as in a Two Stage or Variable speed the system can operate at full blast but can also drop down and provide more even and consistent air.  This has both efficiency and comfort benefits.  More run time = more potential for removing humidity from the home.  It is also quieter.


80% AFUE (minimum) w/ Variable Speed


TRANE XC80 & Ruud RGPE. Both are 80% AFUE and Two Stage.  Each can be matched with Air Conditioning equipment to reach cooling efficiencies exceeding 16 SEER.

Trane XC80 Furnace comparison
RGPE ruud gas furnace

If you live in a warmer state like TX, CA, FL.  80% AFUE efficiency is sufficient.  However, do yourself the service of acquiring a minimum of 2 stage in order to reach for higher cooling efficiencies.  Of course these furnaces must be matched properly to cooling equipment to reach maximum SEER & EER.

Contact us with more questions OR Call Mission for Furnace or AC Repair Houston

AC Repair 77005


David LewisComment