Finding the right gas heater involves balancing fuel type, BTU output, venting requirements, and safety features. The table below summarizes seven top gas heaters across categories: unit heaters, infrared and blue-flame space heaters, a portable propane model, and a high-capacity tankless water heater for whole-house hot water.
| Product | Brand | Type / Key Spec |
|---|---|---|
| Mr. Heater Big Maxx MHU80NG | Mr. Heater | Natural Gas Unit Heater / 80,000 BTU |
| Mr. Heater Big Maxx MHU50NG | Mr. Heater | Natural Gas Unit Heater / 50,000 BTU |
| ProCom MN300HPA-B Plaque Heater | ProCom | Ventless Infrared / 30,000 BTU |
| Dyna-Glo IR30NMDG-1 | Dyna-Glo | Infrared Wall Heater / 30,000 BTU |
| Mr. Heater Portable Buddy MH9BX | Mr. Heater | Portable Propane Radiant / 4,000–9,000 BTU |
| ProCom ML100TBAHR Blue Flame | ProCom | Ventless Propane Blue Flame / 10,000 BTU |
| Rinnai RX199iN Tankless | Rinnai | Condensing Tankless Water Heater / 199,000 BTU |
Mr. Heater Big Maxx MHU80NG
Designed for large spaces, the Mr. Heater Big Maxx MHU80NG is a natural gas unit heater delivering 80,000 BTU and rated for up to 2,000 sq. ft. The package includes the heater, two angle brackets, and a liquid propane conversion kit. Thermostat, hose, and regulator are not included. Unit dimensions are 29.33″ L x 15.50″ W x 26.37″ H.
Venting options are Category 1 vertical or Category 3 horizontal, and installers must maintain a minimum 8 ft. clearance from floor to base of unit. Electrical specs show 120 V and 2.3 amps for the fan and controls. This model suits garages, workshops, and commercial bays requiring high output and hard-mounted installation.
Mr. Heater Big Maxx MHU50NG
The MHU50NG is a natural gas unit heater rated at 50,000 BTU, designed to heat up to 1,250 sq. ft. It features powered exhaust and supports both vertical and horizontal venting. The heater provides outside access to the thermostat, A/C terminals, and gas connection to simplify maintenance without dismantling the unit.
This model targets medium-sized garages, workshops, and light commercial spaces where a balance of output and compact size matter. As a hard-mounted unit, installation should follow venting codes and clearances. Use of a compatible thermostat is recommended for automatic temperature control and energy management.
ProCom MN300HPA-B Infrared Plaque Heater
The ProCom MN300HPA-B is a ventless natural gas infrared plaque heater providing up to 30,000 BTU and heating capacity up to 1,200 sq. ft. It operates without electricity and uses a push-button Piezo ignition. Manual control offers three heat settings: Low, Medium, and High.
Safety features include an Oxygen Depletion Sensor (ODS) with automatic shut-off. The ventless infrared design radiates heat to people and objects rather than primarily heating air, making it suitable for garages, workshops, or supplemental zone heating where venting is impractical. Local codes and indoor air quality considerations should be checked before ventless installation.
Dyna-Glo IR30NMDG-1 Infrared Wall Heater
The Dyna-Glo IR30NMDG-1 is a natural gas infrared wall heater delivering up to 30,000 BTU intended for spaces up to 1,000 sq. ft. It uses infrared technology to radiant-heat objects and occupants, which can feel warmer at lower ambient air temperatures compared to convective heaters.
This model is natural gas ready and does not permit fuel conversion. Wall-mount installation positions the unit to radiate heat across a room or workspace. Consider clearance requirements, mounting height, and local codes for venting or ventless configurations when planning installation.
Mr. Heater Portable Buddy MH9BX
The Portable Buddy MH9BX is a compact propane radiant heater offering adjustable outputs from 4,000 to 9,000 BTU and suitable for spaces up to 225 sq. ft. It delivers radiant, sun-like warmth by directly heating objects and people, making it effective for small enclosed areas, tents, or job-site shelters.
Safety systems include an improved tip-over safety switch that audibly engages if the unit is jostled, and a Piezo igniter for matchless start-up. This model is intended for portable use with propane cylinders and should be used per the manufacturer’s guidelines regarding indoor safety and ventilation.
ProCom ML100TBAHR Blue Flame Space Heater
The ProCom ML100TBAHR is a ventless propane blue flame space heater delivering 10,000 BTU and heating up to 300 sq. ft. It includes a thermostat control that cycles the burner to maintain a set temperature and comes with a wall mount for semi-permanent placement.
This model is specified as not for sale in California or Canada and operates on liquid propane only. Blue-flame heaters produce convective heat that warms air, offering a different feel compared to infrared models. Verify local regulations and indoor air-quality considerations for ventless propane appliances before installation.
Rinnai RX199iN Condensing Tankless
The Rinnai RX199iN is a condensing tankless water heater powered by natural gas or propane with a max output of 199,000 BTU and up to 11.1 GPM, suitable for high-demand residential applications. It installs indoors or outdoors with compatible venting hardware and features a Smart Sense gas control for fuel flexibility.
As a condensing, high-efficiency unit (UEF ~0.98), it offers continuous hot water for multiple fixtures and includes features like Quick Flush and an intuitive interface. This unit represents the gas-heating category for domestic hot water rather than space heating and requires professional installation for venting, gas connections, and compliance with local codes.
Buying Guide
Choosing the best gas heater depends on the intended use: space heating versus water heating, fixed versus portable installation, fuel availability, and local code requirements. The sections below outline key purchase considerations and compare important features across heater types.
Fuel Type And Availability
Determine whether natural gas or propane is available at the installation site. Natural gas is common for permanently installed unit heaters and tankless water heaters, while portable models typically use propane cylinders. Some units include or allow a conversion kit, but many manufacturers restrict fuel conversion, so verify compatibility before purchase.
BTU Output And Coverage
Match BTU output to the space size and insulation levels. High-output unit heaters (50,000–80,000 BTU) are designed for large garages and commercial bays. Mid-range infrared and blue-flame heaters (10,000–30,000 BTU) suit workshops, shrugs, and supplemental indoor rooms. Portable units (4,000–9,000 BTU) are for small areas and quick spot heating.
Heating Technology: Infrared vs Blue-Flame vs Radiant
Infrared heaters radiate heat to people and objects, producing perceived warmth quickly without heating all the air. Blue-flame and convection heaters warm the air which then circulates. Radiant and infrared models are often preferred for drafty spaces or directional heating; blue-flame units can be more uniform for enclosed rooms.
Venting, Installation, And Placement
Vented unit heaters and tankless systems require appropriate venting and clearances. Category-rated venting (Category 1 vs 3) and minimum clearance heights affect placement. Ventless (unvented) heaters avoid flues but impact indoor air quality and may be restricted by local codes. Always consult local regulations and a qualified installer for gas line sizing, venting, and placement.
Safety Features And Indoor Air Quality
Key safety features include Oxygen Depletion Sensors (ODS), tip-over switches, flame failure protection, and automatic shut-off. Ventless appliances produce combustion byproducts and can affect indoor air quality; adequate ventilation and carbon monoxide detection are essential. For occupied living spaces, prioritize units with robust safety certifications and documented installation requirements.
Controls, Thermostats, And Efficiency
Electronic thermostats and built-in controls improve comfort and efficiency by reducing run time. Condensing tankless water heaters deliver high efficiency for domestic hot water needs. For space heaters, variable heat settings, thermostatic control, and programmable operation support energy savings. Confirm electrical requirements for powered fans or control modules.
Portability And Use Case
Portable propane heaters offer flexibility for temporary or remote heat needs and are useful for camping, construction sites, and isolated work areas. Fixed unit heaters and wall-mounted infrared models suit permanent installations. Choose based on whether you need zone heating, full-room heating, or point-spot heating.
Maintenance, Reliability, And Warranty
Review maintenance requirements specific to the technology: burner cleaning, vent inspections, and periodic safety checks. Condensing tankless water heaters require flushing to prevent scale. Verify manufacturer warranty coverage, availability of replacement parts, and authorized service channels to limit downtime and support long-term reliability.
Comparisons And Trade-Offs
– High-BTU unit heaters (e.g., 50k–80k) provide the greatest area coverage but require professional venting and clearance planning.
– Infrared heaters deliver direct warm sensations and may be more efficient in spaces with high ceilings or drafts.
– Ventless blue-flame and plaque heaters simplify installation but may be limited by indoor air quality and local codes.
– Portable propane radiant heaters are flexible and inexpensive to deploy but are limited to small areas and require careful ventilation when used indoors.
| Consideration | Best For |
|---|---|
| High BTU Unit Heaters | Large garages, workshops, commercial bays |
| Infrared / Plaque Heaters | Directional heating, drafts, high-ceiling spaces |
| Blue-Flame Ventless Heaters | Small rooms where venting is impractical (check codes) |
| Portable Propane Heaters | Job sites, tents, temporary heating |
| Tankless Gas Water Heaters | Continuous domestic hot water for whole-house use |
