Mr. HeaterF260550 Big Maxx MHU50NG Natural Gas Unit Heater,Black

Hopefully this review is useful for other, it was hard to find real examples of use like this to get an idea of how well this unit will heat my space. I am heating a 21'x33' garage with an 11' ceiling. Walls are insulated at about an R15 but ceiling with unfinished attic above it is not insulated. Overhead garage door is insulated.Here's the data:Outside temp: 28FGarage Inside temp when heater was turned on: 40F30 minutes after heater on inside temp: 53F1 hour after heater on inside temp: 59F2 hours after heater on inside temp: 65FThe heater was able to get the temp inside the garage up to 70F after about 2.5 hours after not being used all day with an outside temp of 20F the other day as well and it keeps things very nice and comfortable.I cannot speak to reliability as I just purchased, but installation was easy (check Menards for their category 3 horizontal venting kit as it is half the price of the manufacturers kit), and the price was insanely good compared to all of the other options. I was quoted $3500 installed for other brand units from several different local HVAC companies and I was out the door installed (had a local company do part of the install) for around $900 total. I put the unit up and ran electrical but had the installer do the gas line and vent kit install.Since the unit was so inexpensive, I did add the 4 year Amazon protection plan. Hopefully it lasts a long time but if it doesn't, at least it will be easy and free to replace.All in all a good value and it gets the job done.

Update Feb 9. 2024Still going strong. Absolutely NO issues..Update: October 17, 2023I flipped the heater on today after leaving it off since sometime in April.. Its been in the low 50's so I just wanted to take the chill out of the garage and sort out my tools for a fall project.The unit fired right up, warmed up the garage, no issues, just did its job. This unit has been very reliable for me, and I continue to recommend this heater for a garage.-------------------------------------------I bought this heater in September of 2019 when I retired. I live in western NY where the winters are long, dark and cold. Since the wife doesn't want to snowbird in the south, I figured I better heat the garage, so I had a place work on projects.If you can run some natural gas lines and stick a vent through the roof, you will love this heater. I stuck a cheap thermostat on it from one of the big box stores, a separate house switch on it to flip it off for the summer months.I have had NO problems with it. It runs for 6 months during the cold months, then I flip it off at the end of April, when October comes, I flip it back on and it fires right up. It doesn't make any vibrating noise like some have said, vents out the garage roof using the double wall vent duct with a hat to keep the snow out. I insulated my garage walls and ceiling with standard R19 from HD, and drywalled it as well. My garage is 24' x 24' x 10' with concrete floor. This unit heats it with no problem. I should have installed one years ago.Also, I did not use an isolation relay to isolate the unit that protects the house wiring from "a pulse" from the unit when the solenoid kicks on and I have experienced no issues with the unit interfering with the house electric. I have broadband internet, smart switches, smart lights, Alexa, etc.. and have experienced no issues.If you're like me, live in the north and have some DIY skills and are sitting on the fence, just pull the trigger and buy it. You'll get a whole new play area for the winter months. :-)

Update 2021: starting second winter with the 50k btu unit. After a 4 month summer nap she fired right up. No issues. Super happy with its performance so far. See my original post below for details.Original post 2020: I’m heating a fully insulated 700sqft shop with an insulated 18ft garage door and 9ft ceilings. I installed the 50,000btu unit 2 days ago. Install of the unit itself it easy. I screwed two 48” 2x6 to the ceiling making sure to hit ceiling joists. I was able to hold the heater in place while a friend lag screwed its brackets to the 2x6’s. I’d recommend using a sheetrock lift, it was all I could do to hold it in place. It calls for 1” of top clearance and 36” of rear clearance. It also recommends 8ft clearance from floor. With 9ft ceilings I’m only 2” from 8ft.Obviously running the gas line and roof vent are the hardest parts. I won’t get into that work other than to say be sure you use 4” B-Vent for the roof vent. Do not use single wall vent pipe.It’s very quiet and works well. It’s a little deceiving because it quiet and doesn’t blow very hard but it heats my space quickly. 10 degree rise in about 15-20 minutes. I left it on overnight last night. It was 30 degrees outside. I set thermostat on 58 degrees. It only ran for a total of 1hr and 49 minutes over 12hrs to maintain that temp. And that is total time, including cycle on and off time, burner lit time would be even less. The Wifi thermostat I recommend below tracks run time.I also purchased a Wifi thermostat from Amazon. It’s the Sensi ST55. It’s an easy 3 wire hookup with this heater and allows you to download their app and control the thermostat from your phone. Very handy to be able to kick up the heat from the house before I head out to the shop. It also keeps track of how long the heater runs daily. Nice to know how hard your working it.I’ll update this post with any changes over the next year.Final thoughts. The performance of any heater is dependent on not only the size of the space you are heating but the condition of the space; insulation, draft, if there’s a ceiling or not, etc. The 50k btu unit works great in my space (as stated in my first paragraph).Hope this helps others with their decision.