Goodman GMT Furnaces | FurnaceCompare®

Goodman GMT Furnace Overview

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 Filter Size(s)
All 14″ 14x25x1 (bottom)
18x25x1 (side)
All 17-1/2″ 16x25x1 (bottom)
18x25x1 (bottom)
All 21″ 18x25x1 (bottom)
20x25x1 (side)
All 24-1/2″ 18x25x1 (bottom)
24x25x1 (side)

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Consumer Reviews of Goodman GMT


  • Very Satisfied
  • Somewhat Satisfied
  • Neutral
  • Somewhat Unsatisfied
  • Very Unsatisfied
  • #5 of 23 Goodman Furnace
  • 42.86% of customers recommended

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Goodman GMT Furnace Reviews

Showing 6-7 of 7 reviews


1.0 rating
Very Unsatisfied

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.


"Goodman 80% gas split system"

5.0 rating
Very Satisfied

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.

Wichita, KS

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.

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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