Mr. Heater Big Maxx Natural Gas Unit Heater - Powerful Garage Heat

Our review of the Mr. Heater Big Maxx Natural Gas Unit Heater finds it best suited for homeowners and hobbyists who need reliable, high-output heat for garages, barns, and workshops. The main reason to buy is its straightforward, high-capacity performance: the unit pushes warm air using a built-in high velocity fan and delivers up to 80,000 BTU for large spaces, while still running on simple 120V household power. Installation is practical with supplied brackets and external access to thermostat and gas connections, making it a practical option for year-round workspace heating.

Key Features

• High output: The 80,000 BTU model heats large areas efficiently, making it suitable for garages and barns up to about 2,000 sq. ft.
• Flexible venting: Powered exhaust allows either vertical or horizontal venting to fit different building layouts and local code needs.
• Simple electrical needs: Runs on standard 120V and draws only 2.3A, so it requires only basic household power for ignition and fan operation.
• Easy installation: Supplied angle brackets and a one inch mounting clearance requirement make wall or ceiling mounting straightforward for most DIYers or installers.
• Conversion kit included: The package includes a Liquid Propane conversion kit for those who need it, adding installation flexibility without extra purchases.

Who It's For

This heater is ideal for people who need dependable, high-capacity heat in unconditioned spaces like garages, workshops, barns, and hunting shacks. It suits owners who want a unit that vents horizontally or vertically, uses natural gas, and connects to familiar 120V power without running heavy electrical circuits.

It is not the best choice for small indoor living spaces, highly noise-sensitive environments, or locations where a lower-output, ultra-quiet heater is required. If you need a purely electric or portable solution rather than a vented natural gas unit, consider alternate heater types.

Pros & Cons

Pros

• High heat output that can maintain comfortable temperatures in large workshop and garage spaces.
• Powered exhaust and venting options provide installation flexibility for different building layouts.
• Includes LP conversion kit and mounting brackets, which adds value and simplifies setup.
• Low electrical draw on standard 120V circuits keeps wiring simple.

Cons

• Noise level is mixed in user reports, so it may be noticeable in quieter settings.
• Thermostat, hose, and regulator are not included and must be purchased separately.

Specifications

Brand	Mr. Heater
Model / Fuel	Natural Gas unit heater (LP conversion kit included)
Output	80,000 BTU (also available 50,000 BTU model)
Coverage Area	Up to 2,000 sq. ft. (80,000 BTU), 1,250 sq. ft. (50,000 BTU)
Power	120V, 2.3A
Dimensions	29.33 L x 15.50 W x 26.37 H in
Clearance	Minimum 8 ft. from floor to base of unit for installation

Our Verdict

The Mr. Heater Big Maxx is a solid choice for anyone converting a garage or barn into a usable workspace who needs substantial, reliable heat without complex electrical work. It offers high BTU output, flexible venting, and useful installation accessories, making it good value for the price; those sensitive to noise or needing a complete thermostat/regulator bundle should plan for a small additional purchase.

Frequently Asked Questions

Can this unit be vented horizontally?
Yes, the powered exhaust supports both vertical and horizontal venting to suit different installations.

Does the heater include a propane conversion kit?
Yes, a Natural Gas to Liquid Propane conversion kit is included in the purchase.

Is a thermostat included?
No, the thermostat, hose, and regulator are not included and must be sourced separately.