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Goodman GMT Furnace

2.9 of 5 stars 7 reviews | #7 of 20 Furnaces
Updated: Dec 29, 2015 | Read more about Goodman Furnaces | GMT Warranty

Overview of GMT

The Goodman GMT furnace is a discontinued gas furnace that can achieve an AFUE of up to 80 percent. Documents for the GMT reveal that it was first manufactured in 2001, and as late as 2003. The Goodman GMT furnace can be installed either horizontally or vertically, which provides more installation options. The multi-speed blower is sound-insulated for quiet operation, and the heat exchanger is fabricated from aluminized steel. A control board provides diagnostic information should any problems arise with the furnace.

Furnace Filters for the Goodman GMT

Air Flow Configuration Cabinet Width Filters
All 14" 1 14x25x1 filter
(bottom air return)
1 18x25x1 filter
(side air return)
All 17-1/2" 1 16x25x1 filter
(bottom air return)
1 18x25x1 filter
(bottom air return)
All 21" 1 18x25x1 filter
(bottom air return)
1 20x25x1 filter
(side air return)
All 24-1/2" 1 18x25x1 filter
(bottom air return)
1 24x25x1 filter
(side air return)

Consumer Reviews of the GMT

2.9 2.9 of 5 stars 7 reviews
  • Very Satisfied
  • Somewhat Satisfied
  • Neutral
  • Somewhat Unsatisfied
  • Very Unsatisfied
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2 of 5 stars Saint Johns, MI
Date created: 2015-12-29

Nickel and diming me

My furnace is 12 years old and I have to have it fixed every 6 months. Not happy, I'm going broke.

1 of 5 stars Yardville, NJ
Date created: 2014-12-26

Worst furnace ever made!

We had our Goodman furnace installed by George Davis Plumbing & Heating, located in Trenton, New Jersey, in the winter of 2007. The furnace worked fine that winter and we were happy with our purchase. But then our problems started the following year and every year after. And then, after about 3 years, we had to call for repairs on the furnace two and sometimes three times a season. And always on the coldest nights of the year. I would imagine this furnace has cost us about three times the cost of the heater when we first purchased it just in the repairs. Between ignition switches, regulators, mother boards, and every other thing that went bad on this furnace, it is the most unreliable and costly appliance we have in our home. In fact, right now the furnace is not working at 11:30 pm. I will have to call for repair tomorrow morning. In the meantime, I am running on electric plug-in heaters. So please do not buy anything made by Goodman if you want to be warm on cold winter days.

1 of 5 stars Trenton,MI
Date created: 2014-03-09


I wouldn't install a Goodman / Janitrol or as we refer to our old furnace as Junkatrol. This company should not be in business any longer. Even consumer report lists them as Bottom of the proverbial barrel! Bought a Payne furnace to replace it, Best furnace ever!

5 of 5 stars Henrietta, MO
Date created: 2013-03-26

I'm very satisfied with my furnace

I have a Goodman Furnace which I had professionally installed in my home in 2009 (4 years ago) by a licensed hvac Installer. This is the 2nd home I've owned that I had a Goodman Furnace installed in. And I've always had reliable trouble-free service from Goodman Furnaces & ac units. They are the best. Since I had this Goodman furnace installed in my current home in 2009, my gas bill is only about $48 per month during the winter months.. which is less than half of what it cost to operate the aged Trane Furnace that was originally in this house. In the past 4 years that I had my Goodman Furnace installed, I never had any trouble with it. My new Goodman Furnace runs excellent and keeps my home warm & toasty..despite freezing 20 degree winter nights. I recommend Goodman Furnaces & ac units to everyone I know.

5 of 5 stars pierre
Date created: 2012-10-08

All good

I had this unit installed in 2007. I have had no issues or breakdowns. I am very pleased.

1 of 5 stars OAK CREEK
Date created: 2012-01-10


Sure it has a warranty -- but that doesn't mean I enjoy knowing the service tech's dog and kid's name because he is here almost weekly. Simply put, I was tricked into thinking this was a good furnace.

5 of 5 stars Wichita, KS
Date created: 2008-12-13

Goodman 80% gas split system

Installed our system almost 5 years ago. No problems with the units. I used all Goodman components right down to the Lines and cased coil. I am running a 90,000 btu gmt series furnace probably 2003-2004 vintage. And a 13 seer cplq 3.5 Ton condenser unit. Furnace has run great with no problems. a/c unit lost the 2 phase hi voltage contactor but it was my own fault, and during a power outage last summer we tried running the unit with too small a generator. I ended up "chattering" the contactor to death! Parts are very affordable for this furnace if anything were to ever fail. You simply can't go wrong with one of these. The only thing I would change is my home is set up for high static pressure ducting from an old Coleman blend-aire unit. Installed back in the 50's I wish Goodman had a unit with a blower designed to overcome the high static pressures. 3 inch home run venting to all registers from the main plenum. I might upgrade in a few years if a product comes available to suit my needs. But overall I paid $1500 for a complete system at Johnstone Supply. Can't beat that price anywhere Bar none!!! Good Luck and I hope my comments help someone to make the right choice to buy a Goodman.

Other GMT Reviews

A Goodman GMT furnace owner writes to because his furnace repeatedly blows a fuse after it runs for a short time. The experts respond that it is possibly a problem with the wiring, and he should consult an experienced HVAC technician. However, the owner reports that he searched other forums and found that the limit switch was touching the heat exchanger and becoming too hot, causing it to short out. He moved the limit switch slightly, which solved the problem.

A thread on details a discussion about a Goodman GMT gas furnace that will not ignite. Several furnace owners write in that they have had similar problems. One person replies that they cleaned the flame sensor with fine-grain sandpaper, and it corrected the issue.

Another Goodman GMT owner posts a question on about having to clean the flame sensor several times a season to keep the furnace running. An HVAC contractor suggests checking the power wires. The owner responds that this information has helped him locate the recurring problem, and he will be installing a new power wire.

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Goodman GMT Model Numbers

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

Model Number AFUE BTUs per Hour
GMT045-3 80 45,000
GMT070-3 80 70,000
GMT070-4 80 70,000
GMT090-3 80 90,000
GMT090-4 80 90,000
GMT090-5 80 90,000
GMT115-5 80 115,000
GMT135-3 80 135,000
GMT140-5 80 140,000

GMT Warranty

Goodman offers a 20-year warranty on the heat exchanger of the GMT furnace, and a 5-year warranty on all the remaining parts.

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