Best Gas Air Heaters for Garages and Workshops

Choosing the right gas air heater depends on space size, venting, fuel type, and installation preferences. Below is a concise comparison of five top gas air heaters suited for garages, workshops, and larger indoor spaces.

Product	Type	Max BTU	Coverage / Notes
Mr. Heater Big Maxx MHU80NG	Natural Gas Unit Heater	80,000	Up to 2,000 sq. ft., venting categories 1 & 3
Mr. Heater 125,000 Forced Air	Propane Forced Air	125,000	Portable/forced-air, quieter burner tech
Reznor UDXC-45	Natural Gas Unit / Ceiling Mount	45,000	Ceiling-mount, two output levels, 83% efficiency
Dyna-Glo IR30NMDG-1	Natural Gas Infrared Wall Heater	30,000	Infrared radiation, heats objects and occupants
Comfort Glow 25,000 Direct Vent	Natural Gas Wall Heater (Direct Vent)	25,000	Sealed burn direct vent, heats up to 825 sq. ft.

Mr. Heater Big Maxx MHU80NG Natural Gas Unit Heater

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This natural gas unit heater is designed for larger areas such as garages and workshops. It provides 80,000 BTU and is rated to cover around 2,000 sq. ft. The unit ships with two angle brackets and a liquid propane conversion kit, though thermostat, hose, and regulator are not included.

Key specs: 29.33″ L x 15.50″ W x 26.37″ H, 120 V power draw at 2.3 amps, and venting options for Category 1 vertical and Category 3 horizontal installations. Requires a minimum of 8 ft. clearance from floor to the base of the unit.

Use cases: Stationary ceiling- or wall-mounted heating for medium to large indoor spaces where natural gas is available. Ideal when venting flexibility and higher BTU output are needed.

Mr. Heater 125,000 BTU Forced Air Propane Heater

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This forced-air propane heater delivers 125,000 BTU for rapid warm-up of large, open spaces. It features Quiet Burner Technology, claimed to be 50% quieter than standard propane forced-air models, and includes a 10-foot hose and regulator.

Safety and control: The model incorporates a high-temperature limit switch, which helps prevent overheating. Forced-air units move large volumes of air quickly, useful for spaces with poor insulation or high ceilings.

Use cases: Portable or semi-permanent heating in shops, job sites, and well-ventilated garages where propane fuel and robust airflow are acceptable. Consider ventilation for combustion products when using inside.

Reznor UDXC-45 Natural Gas Unit Heater

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The Reznor UDXC-45 is an indoor natural gas heater tailored for commercial and residential workspaces. Rated at nominal 45,000 BTU with two heating levels, it achieves an 83% thermal efficiency.

Mounting and airflow: Designed for ceiling mount with threaded-nut suspension points, it can also be adapted for wall mounting depending on brackets. It uses a low-static propeller fan for quiet forced-air circulation.

Use cases: Workshop, garage, or light industrial applications that need efficient, ceiling-mounted forced-air heating. The two-stage output suits moderate to cold days and improves runtime efficiency.

Dyna-Glo IR30NMDG-1 30,000 BTU Infrared Wall Heater

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This infrared natural gas heater produces 30,000 BTU and heats by radiating energy to warm objects and people rather than primarily heating the air. Infrared technology can feel more immediate in spot heating scenarios.

Features: The unit is natural gas ready and is not permitted for fuel conversion. It can heat up to 1,000 sq. ft. depending on insulation and ceiling height. Infrared units perform well where directional heat and reduced air movement are preferred.

Use cases: Targeted heating of workbenches, specific work areas, or positions in a garage where warmed surfaces and occupants are more important than uniform ambient air temperature.

Comfort Glow 25,000 BTU Direct Vent Natural Gas Wall Heater

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The Comfort Glow direct vent wall heater offers 25,000 BTU with a sealed burn system and matchless piezo ignition. It is designed to heat up to 825 sq. ft., making it suitable for smaller garages and rooms.

Safety features: A sealed combustion chamber and a safety pilot with an internal pressure regulator help stop gas flow if the pilot extinguishes. The space-saving wall mount reduces floor clutter.

Use cases: Indoor spaces requiring sealed combustion for safety and air-quality reasons, such as smaller attached garages or living-adjacent utility rooms where direct venting to the outdoors is available.

Buying Guide: How To Choose A Gas Air Heater

Selecting the right gas air heater requires balancing several factors: space size, fuel type, venting constraints, installation complexity, and safety features. The sections below outline the key considerations and comparison perspectives.

1. Fuel Type: Natural Gas vs. Propane

• Natural Gas: Often more convenient for permanently installed heaters if you have a gas line. Typically lower fuel cost per BTU and suitable for unit heaters and direct vent systems.
• Propane: Common for portable or temporary forced-air heaters. Requires cylinder storage and ventilation planning for indoor use. Good for high-BTU portable applications.

2. Heating Method: Forced-Air, Infrared, Direct Vent, Ventless

• Forced-Air Unit Heaters: Move warm air across the space quickly, good for large or poorly insulated areas. Consider noise and fan placement.
• Infrared Heaters: Radiant heat warms objects and people directly. Effective for spot heating or areas where you want minimal airflow disturbance.
• Direct Vent Wall Heaters: Sealed combustion protects indoor air quality; ideal when outdoor venting is acceptable and safety is a priority.
• Ventless/Blue Flame: No venting needed but increase indoor moisture and require careful compliance with ODS and local codes.

3. BTU Rating And Space Matching

• Estimate space volume (square feet x ceiling height). Larger, poorly insulated spaces need higher BTU outputs. Examples: 25k–45k BTU for small-to-medium garages; 80k–125k BTU for large workshop spaces or warehouse areas.
• Account for insulation, door openings, and ceiling height—these raise required BTU capacity.

4. Venting And Installation Considerations

• Vented/Direct Vent Units require a path for combustion exhaust outdoors. Check category ratings (e.g., Category 1 vs. 3) and local code requirements.
• Ceiling-Mounted Unit Heaters need proper suspension hardware and clearance; confirm minimum clearances from the manufacturer.
• Portable Forced-Air Units still need attention to make-up air and safe indoor use to avoid carbon monoxide risks.

5. Safety Features And Codes

• Look for oxygen depletion sensors (ODS), automatic shut-off, and sealed combustion where indoor air quality matters.
• Ensure pilot and ignition systems meet local building and gas codes. Consider CO detectors and proper ventilation.

6. Efficiency, Controls, And Comfort

• Two-stage or modulating output can improve comfort and reduce fuel waste compared to single-stage high/low models.
• Thermostat compatibility and remote controls improve usability for fixed installations. Hydronic or heat-exchanger options (water-to-air) may integrate with other systems for efficiency.

7. Noise, Air Movement, And Application Fit

• Forced-air heaters move more air and can be noisy; QBT and low-static fans reduce noise. Infrared heaters provide quieter, directional warmth.
• Consider whether warm-air circulation or radiant heat better matches your work patterns (e.g., stationary bench vs. whole-room use).

8. Maintenance, Serviceability, And Warranty

• Choose units with accessible filters, replaceable components, and clear manufacturer support. Commercial-grade units often have longer warranties and heavier-duty construction.
• Schedule annual inspections for combustion systems and follow local code requirements for gas appliances.

Comparison Perspectives

• Best For Large Open Spaces: Higher-BTU forced-air unit heaters (e.g., 80k–125k) provide rapid air turnover.
• Best For Targeted Spot Heating: Infrared wall heaters direct warmth to people and equipment without heating entire volumes of air.
• Best For Indoor Air Quality: Direct vent sealed-combustion models reduce indoor combustion byproducts.
• Best For Portability: Propane forced-air units are often designed for transport and temporary use but require ventilation planning.

Use this guide to match heater type, BTU output, venting needs, and safety features to your specific space and usage pattern. Always follow local codes and manufacturer installation instructions for gas appliances.