Lennox Merit Furnaces | FurnaceCompare®

Lennox Merit Furnace Overview

The Merit furnace series includes three models of gas furnaces all currently produced by Lennox: the ML180, the ML193 and the ML195. The ML180 has an AFUE rating of 80 percent, the ML193 achieves an AFUE of 93 percent, and the ML195 has an AFUE of 95 percent. All models have a sealed blower compartment. In addition, the ML180 has an aluminized steel heat exchanger, while the ML193 and ML195 have a heat exchanger manufactured from stainless steel.

Furnace Filters for the Lennox Merit

Air Flow ConfigurationCabinet WidthFilters
All14-1/2″14x25x1 (bottom)
16x25x1 (side)
All17-1/2″16x25x1 (side)
16x25x1 (bottom)
All21″16x25x1 (side)
20x25x1 (bottom)
All24-1/2″16x25x1 (side)
24x25x1 (bottom)

Questions about this model?

Consumer Reviews of Lennox Merit


  • Very Satisfied
  • Somewhat Satisfied
  • Neutral
  • Somewhat Unsatisfied
  • Very Unsatisfied
  • #2 of 29 Lennox Furnace
  • 60% of customers recommended

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Lennox Merit Furnace Reviews

"Not a fan of Gas Furnaces!"

2.0 rating
Somewhat Unsatisfied

I moved into my house a year and 3 months ago. For the first few months it was summer and I did not use my furnace. Once fall and cold weather hit it was time to turn the furnace on. I have a gas furnace and have only had electric in the past. That being said, I wish I still had an electric furnace! My furnace gets the job done, mostly, but I do not love it. For one thing, it’s about 14 years old, so I know that it is getting closer to its last legs. I don’t like the gas aspect of it, as when it clicks on it has to light the pilot light. I have issues with it actually lighting. At times my furnace will click on four or five times until it finally lights. As one can imagine, this is quite loud. Even when it’s lighting properly and only doing it once, it is a loud process. It has at times woke me up from sleep! So far I have never had to repair it, but I know given its age the time is coming. When I have to replace it, I would have no problem going with the Lennox brand again, but I would most definitely prefer an electric furnace. I would recommend the brand to a friend, but not the particular model of gas furnace. Go with electric!

Lafayette, IN

"Will Never Buy Lennox Again"

1.0 rating
Very Unsatisfied

Faulty Pressure Sensor Switch 1.5 Year Old Furnace Brand new Lennox ML195UH worked great for the first 1.5 years of ownership. Yesterday the furnace failed. Turned out to be a faulty pressure sensor switch. Part was covered by warranty however the couple hundred dollar service bill to come replace the part was not. Service tech mentioned this has been an ongoing problem with this model of furnace. Poor quality control, even worse research and development. Will never buy the Lennox brand again.


"Furnace review"

5.0 rating
Very Satisfied

There are so many things to like about this unit. It is smaller in size, quiet, and energy efficient.

Alliance, Ne

"Considerable difference in the heating bill"

5.0 rating
Very Satisfied

I purchased my furnace from Lynden Sheet Metal of Lynden, Washington. I have had it in my house for about 4 to 5 months and so far, the difference in the heating bill over last year at the same time is considerable. It isn’t that noisy and seems to be operating perfectly. The service was great and prompt. Thank you.

Ferndale, WA

"Merit 80%"

5.0 rating
Very Satisfied

Had a complete Lennox furnace and ac put in by a qualified company that has been around for years, they are so confident in their equipment they put a 15 year parts and labor warranty on the units. These are very quiet you almost can’t hear them run. Great product. I do believe that like everything furnaces do break down however most of the issues are due to not being sized or installed properly. Furnaces do require the technician to set the limits and fan speeds based on your return and duct work. Improper set up will cause premature failure in critical components.


Other Merit Reviews

A thread on gardenweb.com weighs the pros of installing a Lennox Merit ML180 furnace versus one of several proposed American Standard models. At least one expert writes in favor of the ML180, but adds that the homeowner opt for the most efficient single-stage unit available to provide even heating throughout this large home. Other experts protest that the Lennox quote comes from a contractor working with a large discount store.

A new homeowner asks for a comparison between the Lennox Merit series and two Carrier equipment bids on hvac-talk.com. The contractor responds that the products are similar enough that the consumer should make a decision based on who is the better installer. The homeowner feels the Lennox installer has been the more knowledgeable. The expert recommends that the consumer negotiate for a 10-year labor warranty on the Merit series, citing the short warranty as the biggest drawback.

Another post on gardenweb.com reveals a homeowner replacing his 40-year-old Lennox furnace. The consumer has received quotes for three different option in Lennox’s Merit series. The experts feel that Lennox offers a good product, and encourage the customer to select a higher-end option, such as a 90-percent efficient variable-speed furnace, as they suggest he’ll see a return on his investment as he plans to stay in the home at least another 10 years.

Question and Answer


What causes an alternate blinking upon start up?


If the lights are an alternating slow flash then it could be “burners failed to ignite or lost flame 5 times during single heating demand”. If the lights are an alternating fast flash then it could be an “improper main ground”. OR: Line voltage below 90 volts. To see more on the diagnostic codes see page 44 in the manual.

Lennox Merit Model Numbers

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

Model Number AFUE BTUs per Hour
ML193DF045P36B-* 93 44,000
ML193DF070P36B-* 93 66,000
ML193DF090P48C-* 93 88,000
ML193DF110P60C-* 93 110,000
ML193UH045P36B-* 93 44,000
ML193UH070P24B-* 93 66,000
ML193UH070P36B-* 93 66,000
ML193UH090P36C-* 93 88,000
ML193UH090P48C-* 93 88,000
ML193UH110P48C-* 93 110,000
ML193UH110P60C-* 93 110,000
ML193UH135P60D-* 93 132,000

Merit Warranty

Lennox offers a 20-year limited warranty on the heat exchanger in its Merit series products, as well as five-year limited parts and compressor warranties. In addition, the company offers an extended warranty for the ML195 furnace which bumps its 20-year heat exchanger warranty to a limited lifetime offer, and the five-year parts coverage up to a 10-year limited parts guarantee. The extension is available to units ML195DF and ML195UH that are registered online within 60 days of installation.

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