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Mr. Heater F260560 Big Maxx MHU80NG Natural Gas Unit Heater, 80,000 BTU, Black

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$473.10

$ 99 .00 $99.00

In Stock

1.Style:Heater


About this item

  • Your purchase includes One Mr. Heater Big Maxx Natural Gas Heater with 2 angle brackets & Liquid Propane conversion kit | Thermostat, hose & regulator not included
  • Heater dimensions – 29.33” L x 15.50” W x 26.37” H | Coverage area – 2000 Sq. Ft. | Performance – 80,000 BTU | Amps – 2.3 | Voltage – 120 V | Min 8 ft. clearance from floor to base of unit
  • For use with natural gas | Category 1 vertical, category 3 horizontal venting
  • Powered exhaust allows for vertical or horizontal venting | Spark ignition features self-diagnostic control module
  • This heater offers the operating versatility and safety that you have come to expect from Mr. Heater | Limited 3 year warranty on parts and burners


If you are looking to turn your garage or barn into a work space you can use all year-round, you will have to find a safe quiet and reliable heat source. This 80,000 BTU Natural Gas Unit heater is the way to go. It uses a built-in electric high velocity fan to pull cool air into the rear of the heater, across a heat exchanger, then forcing warm air into the surrounding areas. These heaters only require 115v AC power and can be vented vertically or horizontally - please check local codes and restrictions. With a mounting clearance of only 1 inch, the supplied brackets, external access to power, and thermostat connections - installation is a cinch. With the Durable Spark ignition and robust factory standard self diagnostic control module, we can offer a 3 year factory warranty on all parts and burners and a 10 year warranty on any defects in the heat exchanger. This heater offers the operating versatility and safety that you have come to expect from Mr. Heater.


Magicolor
2025-09-04 10:59:44
Delivered quick, installed and works great. Keeps the entire garage hot and sometimes we need to take out coats off if we are in the garage. It is well below zero and this keeps up with a 2 large two car garage. My gas bill did go up but it sure beats the propane tanks and smell.
Ayman othman
2025-08-28 12:12:53
Its heat up my outdoor patio like really good also its simple to controll it .. the only thing dont install it unless you know what you exactly doing
Nancy Finnerty
2025-08-07 15:35:30
Great heater, great value. Put it to use in my three car detached garage. The garage is fully insulated and thus the heater warms it easily. Some complained it was loud/noisy, I did not find that to be true. Instructions easy to follow for an experienced Do It Yourself. I am very pleased with it's performance and value, you will be too.I needed a propane conversion kit, it was not in the box, I think it fell out perhaps because the box showed up pretty beat up. The heater was damaged a bit, cosmetic mostly. But I did call help desk at Mr. Heater and they were very helpful and sent a propane conversion kit within the week. Got it installed without a problem.Would have given 5 stars if the packaging had been better. Mr heater could design better packaging. Hope they do.You won't be disappointed.
Jason S. Cooper
2025-08-02 17:14:18
This heater has been more effective than I anticipated. The installation wasn’t bad (I did it all by myself) and I had it up and running in three days. Two of those days were running the thermostat and ventilation pipe. I had contacted a couple heating companies prior to this purchase and they all wanted to charge me $1800 for a similar unit. Great buy!
David C.
2025-07-30 14:00:28
This is my second Mr Heater, I have a 50 btu unit as well. The 50k worked for 3 weeks before it stopped working and this one worked for about 1 minute. I fired it up and it worked perfectly. T'he next day the fan would not kick on. Have already been on the phone on hold for about 45 min before leaving a call back number. They will call back, ask me some questions, then say they are sending out a new circuit board, which is what my other one needed also. I'm being generous by giving them a 3 star review, but i'm keeping in mind the cost of the unit which is a really good value. I really like the heater, I just don't know if i can depend on it. Every time i've been on hold with them the recording says they are receiving unusually heavy call volume. Since they clearly know they are selling an unreliable product, it would be nice if they would hire more service tech advisors. I probably spent 3-4 hours with my other heater between time on hold, diagnostic time and actually replacing the circuit board. If you don't like working on stuff you might want to look at a different brand. If you do decide to purchase one just plan on doing your own diagnostics and repairs.Update 1/29/2020- Have been on the phone 3 times doing diagnostics on this heater. It is working but the problem now is that it cycles on and off about every 30 seconds to 2 minutes. I have been asked to checked the voltages in and out of the circuit board and check the pressures sn column of water. The last guy had me disconnect the pressue switch and bypass it. The heater ran for several minutes while he stayed on the phone so he sent me out a new switch. I installed it and it is still cycling. Back on the phone for the long hold and unusual call volume. They called back after a couple of hours and said they were sending me a new control board.3/25/2020 Installed new control board. Heater still cycles on and off. I'm not getting back on the phone with this company again. Still heats my shop, just not nearly as efficiently as it should. Not very happy overall. Paid new price for a brand new heater and Ive wasted hours of my time for something that has never worked properly and never will.
fghtds
2025-07-12 10:50:40
Just got finished with the install. Test ran it for about 15 minutes. I think it’s going to work great in my 40 x 60 shop this winter. Note: several of the negative reviews stated that it would run for a short time then shut off. I had this problem too. The back pressure sensor is really sensitive. I had made a grill for the outside vent. Apparently I didn’t drill enough 3/8” holes in it. I found a better one and it quit tripping the ‘back pressure’ code. Also, I’ll bet a least a couple of those negative reviews were trying to run it on propane with the NG jets in it. They look the same and have the same 3 numbers. Just in a different order.
Jeffrey A. Davies
2025-07-11 16:47:01
Heats all 3of garage stalls
rod farrell
2025-05-30 14:03:46
Easy install, very compact for size
Magicolor
2025-04-27 18:10:27
Delivered quick, installed and works great. Keeps the entire garage hot and sometimes we need to take out coats off if we are in the garage. It is well below zero and this keeps up with a 2 large two car garage. My gas bill did go up but it sure beats the propane tanks and smell.
Ayman othman
2025-04-23 11:59:22
Its heat up my outdoor patio like really good also its simple to controll it .. the only thing dont install it unless you know what you exactly doing
Nancy Finnerty
2025-04-21 14:50:52
Great heater, great value. Put it to use in my three car detached garage. The garage is fully insulated and thus the heater warms it easily. Some complained it was loud/noisy, I did not find that to be true. Instructions easy to follow for an experienced Do It Yourself. I am very pleased with it's performance and value, you will be too.I needed a propane conversion kit, it was not in the box, I think it fell out perhaps because the box showed up pretty beat up. The heater was damaged a bit, cosmetic mostly. But I did call help desk at Mr. Heater and they were very helpful and sent a propane conversion kit within the week. Got it installed without a problem.Would have given 5 stars if the packaging had been better. Mr heater could design better packaging. Hope they do.You won't be disappointed.
Jason S. Cooper
2025-04-06 14:45:14
This heater has been more effective than I anticipated. The installation wasn’t bad (I did it all by myself) and I had it up and running in three days. Two of those days were running the thermostat and ventilation pipe. I had contacted a couple heating companies prior to this purchase and they all wanted to charge me $1800 for a similar unit. Great buy!
David C.
2025-02-25 10:53:56
This is my second Mr Heater, I have a 50 btu unit as well. The 50k worked for 3 weeks before it stopped working and this one worked for about 1 minute. I fired it up and it worked perfectly. T'he next day the fan would not kick on. Have already been on the phone on hold for about 45 min before leaving a call back number. They will call back, ask me some questions, then say they are sending out a new circuit board, which is what my other one needed also. I'm being generous by giving them a 3 star review, but i'm keeping in mind the cost of the unit which is a really good value. I really like the heater, I just don't know if i can depend on it. Every time i've been on hold with them the recording says they are receiving unusually heavy call volume. Since they clearly know they are selling an unreliable product, it would be nice if they would hire more service tech advisors. I probably spent 3-4 hours with my other heater between time on hold, diagnostic time and actually replacing the circuit board. If you don't like working on stuff you might want to look at a different brand. If you do decide to purchase one just plan on doing your own diagnostics and repairs.Update 1/29/2020- Have been on the phone 3 times doing diagnostics on this heater. It is working but the problem now is that it cycles on and off about every 30 seconds to 2 minutes. I have been asked to checked the voltages in and out of the circuit board and check the pressures sn column of water. The last guy had me disconnect the pressue switch and bypass it. The heater ran for several minutes while he stayed on the phone so he sent me out a new switch. I installed it and it is still cycling. Back on the phone for the long hold and unusual call volume. They called back after a couple of hours and said they were sending me a new control board.3/25/2020 Installed new control board. Heater still cycles on and off. I'm not getting back on the phone with this company again. Still heats my shop, just not nearly as efficiently as it should. Not very happy overall. Paid new price for a brand new heater and Ive wasted hours of my time for something that has never worked properly and never will.
fghtds
2025-02-03 16:19:21
Just got finished with the install. Test ran it for about 15 minutes. I think it’s going to work great in my 40 x 60 shop this winter. Note: several of the negative reviews stated that it would run for a short time then shut off. I had this problem too. The back pressure sensor is really sensitive. I had made a grill for the outside vent. Apparently I didn’t drill enough 3/8” holes in it. I found a better one and it quit tripping the ‘back pressure’ code. Also, I’ll bet a least a couple of those negative reviews were trying to run it on propane with the NG jets in it. They look the same and have the same 3 numbers. Just in a different order.
Jeffrey A. Davies
2025-01-21 09:04:10
Heats all 3of garage stalls
rod farrell
2025-01-18 18:46:31
Easy install, very compact for size
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