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Lennox G26 Furnace

2.6 of 5 stars 15 reviews | #15 of 26 Furnaces
Updated: Dec 16, 2018 | Read more about Lennox Furnaces | G26 Warranty

Overview of G26

The Lennox G26 (discontinued) is a high-efficiency gas furnace offering 92% AFUE. This model was offered in in 4 different models with downflow and horizontal options.

The G26 was equipped with Lennox's SureLight ignition system, which featured easy on board diagnostics with LED lights and was made of durable, silicon-nitride for long-lasting home heating.

Fully insulated cabinets and heating capacities of 50,000 to 125,000 BTUH are additional components of this unit.

Furnace Filters for the Lennox G26

Air Flow Configuration Cabinet Width Filters
All 16 1/4" 1 14x25x1 filter
All 21-1/4" 1 20x25x1 filter
All 26-1/4" 1 20x25x1 filter

Consumer Reviews of the G26

  • Very Satisfied
  • Somewhat Satisfied
  • Neutral
  • Somewhat Unsatisfied
  • Very Unsatisfied
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5 of 5 stars Lima,OH
Date created: 2018-12-16


19 years old trouble free, I just replaced flame sensor and igniter by myself, mainly because I felt the flame sensor was kicking it off sometimes, it has 2 led lights and trouble code info on manual.

1 of 5 stars New England
Date created: 2017-01-06

CO Event and cracked heat exchanger

Thank heaven we added a co detector in our home and I encourage everyone to do the same! Had a co event that required a fire department response to evacuate the home and ventilate to remove dangerous co levels. Gas company said they never saw such high readings from a furnace. Furnace maintained annually by gas company and they were surprised at high levels of co output and internal cracks that leaked. When Lennox contacted they assume no responsibility and claim that any warranty had expired less than 60 days ago. This is a good news story where no one was injured. Who knows what would have happened without a detector. Resulted in a solemn promise by my family never to own a Lennox product again. I would urge you not to buy as well.

5 of 5 stars Arthur Canada
Date created: 2016-11-11

G26 has proven to be reliable

Had the furnace installed in 2002. The furnace that came with the house was a piece of junk can't remember the brand but it wasn't a high efficiency. Only had one issue in 2014 and that was water getting into the blower. I am on a maintenance plan which I think is a good idea for any furnace. We have a 1200 sq. Ft house and the furnace does a good job keeping it warm. I dislike that I can't operate the blower motor in the summer to help circulate the colder air from the basement. (May be an installation oversight I don't know). I would buy another Lennox.

5 of 5 stars Oxford,OH
Date created: 2016-10-05

No problems

I got my G26 Lennox furnace installed in 1999 (17 years ago) under the "Pulse Program", for the tidy sum of $640.00, and have never had a problem with it! Just replaced it due to its age, to insure trouble free service throughout the winter. If this new "Merit Series 14ACX" works as good as the last one, I will be very happy!

1 of 5 stars Indiana
Date created: 2015-11-15

Do you like pain

Run like hell from this Lennox furnace. I've got a new born baby in the house and this junk of a furnace is always down. Heat exchanger, pressure switch, induction fan, water leaks and more, except heat. Run like hell from this brand. Again, look at the other reviews and buy another brand unless you like pain, thanks.

1 of 5 stars Newark, OH
Date created: 2012-12-27

Save yourself the headache, avoid Lennox

We have 2 Lennox g26q3 furnaces at in our local Historical Society Museum, plus three more Lennox furnaces in an other building. To put it short - they are junk; poorly designed and built with cheap components. The two g26q3 furnaces both fail 2-3 times a year, typically on a holiday. (I've become really good at repairing them). The two newer Lennox furnaces, (different models) at the other facility typically fail once a year. The only one that rarely has an issue is the 25 year-old "inefficient" furnace. The whole "high efficiency" design is a joke, because you will spend more on parts and service than you will save on your gas bill!

1 of 5 stars Michigan
Date created: 2012-01-17


I have had to fix it every year since I had it. Turns out the dealer was very unreputable and went out of business soon after installation. I have done all repairs myself and every year I repair something new on it. I would never buy another lennox product ever!

1 of 5 stars PA
Date created: 2011-10-26


Not sure what exact one, but I am for sure it is a g26. 7 years ago my parents had carbon monoxide all through their house due to a heat exchanger cracking and now 7 years later it cracked again and was leaking carbon monoxide again all through the house. So now they have to sit in the cold with no heat until this part comes in, which they haven't even ordered yet (been 2 days)! Not only do my parents live there but so does my 88 year old grandma and 2 year old niece. Called Lennox corporate and complained because the part is still under warranty but what about the over $500 repair fee that it costs?! Their answer to this was.... That's your problem not ours..

5 of 5 stars Charlotte, NC
Date created: 2010-01-14

Lennox G26

I live in Charlotte NC and I've had a Lennox g26 for 11 years without a single hiccup. Perfectly quiet. It's mounted in a basement, so it's at a pretty constant temperature and reasonable humidity. I could see where a unit mounted in an attic could have service life issues here.

5 of 5 stars
Date created: 2009-10-15

Home owner

I had a lennox g26 installed in my home 12 years ago and I have been very satisfied with it. I have never had a repair of any kind, I simply replace the filters regularly. This 40,000 btu unit replaced a 120,000 btu unit and though it has longer cycle times, it has never failed to keep us warm.

1 of 5 stars
Date created: 2009-04-10

Furnace from Hell

When I built my house in 1997 I installed a Lennox Elite g26. It has never worked for more than a few months at a time and has never made it through an entire heating season. Two circuit boards, heat exchanger, fan motor have all been replaced. Last year a wiring harness caught fire due to a short in a plugged connection. For the first 10 years the dealer replaced the parts and fixed it at no charge to me. Each time it was fixed we thought that would be the end of our trouble, only to have it go out again in a few months. Now they want to charge to fix it. It broke this past January, cost me almost $200 to fix it. Now in April it is leaking exhaust fumes into the house setting off carbon monoxide detector, so we shut it off. I have had it and won't pay to fix this lemon. We asked Lennox to give us a new furnace, no reply as of yet.

1 of 5 stars Jones, MI
Date created: 2009-03-05

Lou Simmons

Purchased a complete System, Heat Pump/Air and a propane high efficiency g26q3-75-5 furnace. I have a four zone system. Heat exchanger failed this past winter. Serviceman switched power off to furnace in mid Jan. Lennox dealer ordered replacement but wanted $510.00 for labor. Lennox warranty states free replacement for the heat exchanger but will not supply heat exchanger to home owner nor will the Lennox dealer who has my heat exchanger supply it to another licensed installer. Lennox is protecting the Lennox dealers. Never buy Lennox again. Wish I new of a unit that would be a direct replacement and get rid of the Lennox junk.

5 of 5 stars St. Louis, MO
Date created: 2008-12-18

Lennox G26

Installed a Lennox G26 14 years ago and have been very pleased with this unit. VERY energy efficient, I think even more than it is rated. Have had two parts replaced. An ignition switch and a blower control motor. I have noticed, over the years, the combustion air induction motor has gotten louder, with a sort of "vibration" sound. I guess after 14 years it may be dirty and/ or wearing out. The cost for the Lennox replacement part is about $250. Not sure how much labor would be to replace it. I plan to do it my self, as it seems easy. So all in all, I've been very pleased with the efficiency and have had just two problems over 14 years. I've had a service/maintenance agreement on the unit for most of the 14 years: heating checked once in the winter and a/c in summer.

1 of 5 stars Salt Lake City, UT
Date created: 2008-02-23

During the ten years since I had this furnace installed (a G-26 model I believe) I have had a failure every year. The first three years I got warranty coverage then the installer went out of business so I pay again and again. I've replaced the blower motor two times; the low pressure switch; the draft inducer motor; the circuit board (which has apparently failed again so I'm looking to replace the furnace instead). The flame sensor needed cleaning every 6 weeks until one repairman jury rigged a non-standard sensor that really works about 4 years ago and the igniter was replaced a couple of winters back. I added it up and I've payed for this furnace 3 times in 10 years. No More.

1 of 5 stars minnesota
Date created: 2008-01-19

I have owned a Lennox G26 for 12 years and finally decided to give up on it. It has been nothing but trouble since the day it was installed and is in need of constant repair. Chose Trane this time because of consumer reviews.

Other G26 Reviews

Although many HVAC contractors support Lennox products online, some consumer posts reflect disappointment and frustration with the G26. A consumer on finds the LED diagnostic lights not very useful when trying to diagnose a system error. Simple fixes, consumers say, are made more complicated because the lack of activity on the board.

A conversation thread on highlights repairs, failing components, and hard-to-deal with repairmen. also has many repair questions about the G26. From faulty ignitions to blowing cold air, consumers are unsure how to fix the unit without calling a professional.

Question and Answer


What is the efficiency of the lennox G23Q3/4-100-2


80% AFUE

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Lennox G26 Model Numbers

The G26 is available in different models which vary in efficiency and capacity.

Model Number AFUE BTUs per Hour
G26Q2-50* 92.3 50,000
G26Q3-4-100* 92.3 100,000
G26Q3-4-125* 92.3 125,000
G26Q3-50* 92.4 50,000
G26Q3-75* 92.3 75,000
G26Q4-5-100* 92.3 100,000
G26Q4-5-125* 92.3 125,000
G26Q4-5-75* 92.3 75,000

G26 Warranty

The G26 was equipped with Lennox's basic warranty. The product did not require registration and is automatically eligible for receive a lifetime limited heat exchanger warranty and 5-year limited covered components warranty.

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