#1 Home Improvement Retailer

Internet # 305089828

Model # MHU50NG

Store SKU # 1007544730

50,000 BTU Black Big Maxx Natural Gas Unit Space Heater

$452.79
Apply Now
Pay $402.79 after $50 OFF your total qualifying purchase upon opening a new card. 
Apply for a Home Depot Consumer Card
  • Indoor 50,000 BTU forced air propane or natural gas unit heater
  • Heats up to 1,667 sq. ft., or approximately a 3-car garage
  • Ceiling mounted forced air unit heater for garages, barns, etc.
  • View More Details

Free & Easy Returns In Store or Online

Return this item within 90 days of purchase.

Read Return Policy

Ask about this product

Get an answer now with AI

AI-generated from the text of manufacturer documentation. To verify or get additional information, please contact The Home Depot customer service.

Product Details

About This Product

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 50,000 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 115 V AC power and can be vented vertically or horizontally - please check local codes and restrictions. With a mounting clearance of only 1 In., 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.

Highlights

  • Ceiling-mounted forced air unit heater turns garages, barns, and workshops into heated workspaces
  • Compatible with standard 24-volt or new Wi-Fi enabled thermostats (sold separately)
  • 50,000 BTUs heat up to 1,667 sq ft, or approximately a 3-car garage
  • Spark ignition features self-diagnostic control module
  • Return Policy
  • California residents
     see Prop 65 WARNINGS

Product Information

Internet # 305089828

Model # MHU50NG

Store SKU # 1007544730

Specifications

Dimensions

Product Depth (in.)

24 in

Product Width (in.)

25.5 in

Details

Area Heated (sq. ft.)

1667 sq ft

Color

Gray

Color Family

Gray

Control Type

Mechanical

Features

Quiet Operation

Fuel Rate (gallons/hour)

0 gal (US)/min

Fuel Tank Capacity (gal.)

0 gal

Heat rating (BTU/hour)

50000 Btu/h

Heater Type

Natural Gas

Heating Method

Forced Air

Ignition Type

Continuous Spark

Indoor/Outdoor

Indoor

Location Use

Garage

Maximum Temperature Setting (F)

0 °F

Number of Heat Settings

1

Portable Heater Features

Thermostat

Power/Fuel Type

Natural Gas

Product Weight (lb.)

59.08 lb

Returnable

90-Day

Room Size

Extra Large

Runtime (hours)

0 hr

Vent Type

Ventless

Warranty / Certifications

Certifications and Listings

CSA Certified

Manufacturer Warranty

3 Years parts, 10 year Heat Exchanger

Questions & Answers

Does this unit include a propane conversion kit
ByAug 6, 2026
1 Answer | 
Answer This Question

Thank you for your inquiry. Yes, this unit comes with a conversion kit, so you can run it on propane or natural gas. Have a great day!

By|Aug 7, 2026


    What voltage amps for the 125,000 heater?
    ByJun 8, 2026
    1 Answer | 
    Answer This Question

    Thank you for your inquiry. This heater requires 3 amps of power. Have a great day!

    By|Jun 9, 2026


      Does this need dedicated electrical circuit
      ByJun 3, 2026
      1 Answer | 
      Answer This Question

      Thank you for your inquiry. Yes, this heater should be wired in on its own circuit. Have a great day!

      By|Jun 4, 2026


        Can this be converted from Natural gas to propane?
        ByApr 13, 2026
        2 Answers | 
        Answer This Question

        My garage is 12ft wide, 20ft long,9ft ceiling how many sq ft is that

        By|Apr 23, 2026

          Thank you for your inquiry. Yes, this heater includes a conversion kit if you would like to switch to propane. Have a great day!

          By|Apr 14, 2026


            need it to be lp gas
            ByMar 31, 2026
            1 Answer | 
            Answer This Question

            Thank you for the inquiry. These heaters come with a conversion kit inside. Have a great day!

            By|Mar 31, 2026


              Does the fan shut off once temp the thermostat is set to is reached
              ByDec 6, 2025
              1 Answer | 
              Answer This Question

              Thank you for your inquiry. Yes, the fan will run for a few minutes after the heat shuts down, and then will stop itself until the heater starts back up. Have a great day!

              By|Jun 27, 2026

                (1)

                Can you vent this into a chimney that has a liner?
                ByDec 1, 2025
                1 Answer | 
                Answer This Question

                Thank you for your inquiry. Yes, this heater can be vented into a lined chimney. For full instructions on how to do so, consult the heater's owner's manual. Have a great day!

                By|Dec 2, 2025


                  Can I splice the vent into a 6" wood stove pipe in order to vent outdoors?
                  ByNov 17, 2025
                  1 Answer | 
                  Answer This Question

                  Thank you for your inquiry. No, you should not combine the venting for those two heaters. Have a great day!

                  By|Nov 18, 2025


                    Viewing 1-8 of 104

                    Customer Reviews

                    4.4 out of 5

                    • 4.4 out of 124 reviews
                    • 85% recommend this product
                    Filter by:
                    Showing 1-10 of 124 reviews
                    50000 BTU Mr Heater Big Maxx
                    I bought it in 2020 for $300+. Installed it by myself. Pretty easy to install if you know what your doing. Hanging it on the ceiling was a little challenging by myself, could have used a buddy. At this time I have used the heater for 5 winter seasons in ND. I have had no issues with it and I am very happy. I use it to heat my 20' x 24' shop that I built. Can't believe the prices on the current models.
                    by
                      • Recommended
                      This customer chose to rate the product and not provide text.
                      by
                      • Verified Purchase
                      The box was beat up when it was delivered. The fan motor was not installed and lose. Found the bolts in the bottom of the box. Removed the fan shroud and remounted it. Fan blade was bent a little. Glad we saw it before we installed the heater on the ceiling. This is a two man project to mount. Hooking it all up was straight forward. Fired right up and has been running good. Not as quite as some said. All in all I’m happy with everything.
                      by
                      • Verified Purchase
                      This customer chose to rate the product and not provide text.
                      by
                      • Verified Purchase
                      I have not installed yet, all indications it will work great
                      by
                      Care of delivery is terrible. Box smashed and unit dented. It is a shame that the shipping in this country is so bad. "Just give my your money and shut up" is the philosophy of big business any more.
                      by
                      Response from Mr. Heater Product ExpertAug 5, 2026
                      We are very sorry for the shipping inconvenience. It is certainly frustrating when an expensive purchase arrives with shipping damage. Please call s at 1-855-663-0660 so we can evaluate the situation and help to determine the best course of action to resolve this as quickly as possible. Enerco
                      • Verified Purchase
                      1 found this review helpful
                      The heater was initially out of stock but I was able to request notice when it became available. Home Depot sent me an email letting me know my item was back in stock and available to order. The Heater was hundreds less than elsewhere and has been operating flawless. In short. Great service, fast shipping, and amazing deal. Definitely would recommend both the heater and Home Depot to family and friends
                      by
                      easy and quick to install; easy to convert to propane; fired right up
                      by
                      • Verified Purchase
                      Don't, Just Don't!
                      I have one about 3 years old in Michigan, for a small attached home greenhouse. Keeps failing, they've replaced gas valve pressure valves etc. The owner of the residence is away for the winter. Parts take forever to receive by the HVAC servicer. And this has been an ongoing since November. I installed a camera pointing at a temperature gauge. It works when it wants to. Most of the time I have to go over there flip the switch to get it to reset. Spend the extra money and buy a better product.
                      by
                      Response from Mr. Heater Product ExpertFeb 2, 2026
                      Thank you for your review and feedback. We'd like to speak to you about your experience with this unit. Please give us a call at 1-855-663-0660. Enerco
                        • Recommended
                        No
                        I have a 50,000 bigmaxx garage furnace, 2nd year of running it, when it operates good heater, i have a problem with it every year, and if you need to have hvac come and service it another 300.00 dollars shot, this unit cost 500.00 dollars, so my experience with this heater has been bad and if it goes out goes out again then I will be looking at a commercial heater, so my review is if you can afford a little more money on a garage heater that's the path I would take .
                        by
                        Response from Mr. Heater Product ExpertJan 5, 2026
                        Thank you for your review and feedback. We'd like to speak to you about your experience with this unit. Please give us a call at 1-855-663-0660. Enerco
                          • Recommended
                          Showing 1-10 of 124 reviews

                          Compare Key Features

                          current item

                          Product Snapshot

                          Ideal for homeowners looking for powerful heating, making garage transformations easier.
                          Ideal for supplemental heating needs, this heater boasts 30, 000 BTU output, dual fuel options, and a user-friendly design.
                          Ideal for drafty or windy areas like loading docks and mechanic bays, this heater provides instant, cost-saving comfort. Built for durability with a 10-year burner assembly warranty.
                          Ideal for transforming garages or workshops into year-round workspaces, this heater offers powerful forced air heating with a 125, 000 BTU output, ensuring optimal warmth and comfort even in large areas.

                          Heating Capacity (BTU)

                          50, 000 BTU
                          30000
                          60, 000 BTU
                          125, 000

                          Heating Method

                          Forced Air
                          Radiant
                          Radiant
                          Forced Air

                          Oxygen Depletion Sensor

                          Tip-Over Shut-Off

                          Indoor/Outdoor Use