Commercial gas heaters serve warehouses, garages, restaurants, and multi-unit facilities with high-output, reliable heat. Below is a concise comparison of five commercial-grade gas heating solutions selected for performance, installation flexibility, and industry suitability.
| Product | Type | BTU / Flow | Installation |
|---|---|---|---|
| Rinnai CX199iN | Condensing Tankless Water Heater | 199,000 BTU / 11.1 GPM | Indoor/Outdoor, Natural Gas or Propane |
| Rinnai CU160eN | Condensing Tankless Water Heater | 160,000-ish Equivalent / 9 GPM | Outdoor Tankless, Natural Gas |
| Mr. Heater Big Maxx MHU80NG | Unit Heater | 80,000 BTU | Wall Or Ceiling, Natural Gas |
| Reznor UDXC-150 | Ceiling-Mount Garage/Warehouse Heater | 150,000 BTU (Dual Output Levels) | Ceiling Or Wall, Natural Gas |
| American Standard D-100-270-AS | Storage Water Heater (Commercial) | 270,000 BTU / 100 Gallon | Indoor Commercial Water Heater, Natural Gas |
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Rinnai CX199iN Condensing Tankless Water Heater
This Rinnai condensing tankless unit is sized for commercial hot water demand with 199,000 BTU and up to 11.1 GPM. It supports both natural gas and propane via the Smart Sense gas control and is installable indoors or outdoors using the Versa Vent and RX-OVC vent cap for outdoor setups.
Key features include 97% thermal efficiency for lower energy consumption and an optional conversion kit to enable recirculation, improving hot water management for multiple fixtures and reducing wasted energy. The compact tankless form saves mechanical room space compared with storage boilers or tanks.
Suitable Applications: Multi-tenant buildings, commercial kitchens, and facilities requiring high continuous hot water flows and flexible fuel or venting options.
Rinnai CU160eN Commercial Tankless Heater
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The CU160eN is an outdoor commercial condensing tankless water heater designed to deliver up to 9 GPM at commercial demand levels. Its space-saving design installs on exterior walls to free interior mechanical space.
Notable features: Circ-Logic recirculation patterns to reduce wait time for hot water, multiple venting options for installation flexibility, and Wi‑Fi monitoring capabilities for remote performance tracking. The unit heats only when needed, optimizing energy usage for businesses with intermittent hot water needs.
Suitable Applications: Restaurants, small laundromats, remote mechanical rooms, and facilities that prefer outdoor appliance mounting to reduce indoor venting infrastructure.
Mr. Heater Big Maxx MHU80NG Unit Heater
The Mr. Heater Big Maxx MHU80NG is an 80,000 BTU forced-air unit heater intended for garages, workshops, and similar commercial spaces. It includes mounting brackets and can convert for propane with the included kit, though thermostat, hose, and regulator are not included.
Product details emphasize area coverage up to roughly 2,000 sq. ft., 120 V operation for fan power, and clearances that must be respected for safe installation. Venting categories provided include Category 1 vertical or Category 3 horizontal configurations depending on site requirements.
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Suitable Applications: Open shops, garage bays, service areas where direct forced-air heat and quick warm-up are priorities.
Reznor UDXC-150 Ceiling Mount Commercial Heater
The Reznor UDXC-150 is a 150,000 BTU natural gas heater with two firing levels for adaptability to changing conditions: low fire ~87,150 BTU and high fire ~124,500 BTU. The unit achieves about 83% thermal efficiency and is designed for ceiling or wall mounting with suspension points.
It features a low-static propeller fan for quiet forced-air distribution and a horizontal Category 1 B-venting kit option. The UDXC series targets industrial spaces such as warehouses and workshops where distributed overhead heat and robust output are needed.
Suitable Applications: Large-span areas that benefit from overhead heat distribution, including manufacturing bays and large garages.
American Standard D-100-270-AS Commercial Water Heater
This American Standard commercial storage heater is a heavy-duty 100-gallon unit with 270,000 BTU input, constructed for longevity with an inner Dura-glas lined tank fired at 1,600°F and four sacrificial anode rods for corrosion protection.
Insulation uses non-CFC foam to maximize heat retention. The tank approach provides a buffer for high peak demands or processes requiring large volumes of stored hot water, making it a different solution compared with tankless condensing products.
Suitable Applications: Facilities with large intermittent hot water draws, institutional kitchens, laundries, and systems where storage capacity improves resiliency and peak handling.
Buying Guide For Commercial Gas Heaters
Selecting a commercial gas heater requires matching heating technology to the facility’s operational profile. This buying guide outlines the key factors to evaluate and compares different perspectives to aid a facility manager or contractor.
Tips for Getting the Best HVAC Prices
- Prioritize Quality Over Cost
The most critical factor in any HVAC project is the quality of the installation. Don’t compromise on contractor expertise just to save money. - Check for Rebates
Always research current rebates and incentives — they can significantly reduce your overall cost. - Compare Multiple Quotes
Request at least three estimates before making your choice. You can click here to get three free quotes from local professionals. These quotes include available rebates and tax credits and automatically exclude unqualified contractors. - Negotiate Smartly
Once you've chosen a contractor, use the proven strategies from our guide — How Homeowners Can Negotiate with HVAC Dealers — to get the best possible final price.
Heat Type And Application
- Space Heaters / Unit Heaters (e.g., Mr. Heater, Reznor): Designed to deliver forced-air or radiant heat directly into workspaces. Best for warehouses, garages, and areas where quick warm-up and direct heating are needed.
- Water Heaters (Tank Or Tankless) (e.g., Rinnai, American Standard): Provide hot water for processes, sanitation, or domestic-style needs. Tankless condensing units favor continuous flow and energy efficiency; large tanks offer buffering for peak loads.
- Infrared / Radiant Options: Not covered in the five selected units but relevant where direct object heating is desired without large air movement.
Capacity And Output
- BTU Rating vs. Space: Match BTU output to the heated volume and expected temperature rise. Manufacturers provide coverage estimates—verify against building heat loss calculations.
- Flow Rate For Water Heaters: For tankless units, confirm GPM at expected incoming water temperatures. Higher GPM supports multiple simultaneous draws.
- Multi-Level Output: Units with staged firing (e.g., Reznor) help adapt output to milder days and improve efficiency.
Efficiency And Operating Cost
- Thermal Efficiency: Condensing tankless units (Rinnai models) can reach high efficiencies (mid-to-high 90s %), reducing natural gas consumption for water heating.
- Standby Losses: Storage tanks incur standby losses; well-insulated tanks mitigate this. Tankless units eliminate standby loss but may require higher initial cost and complexity.
- Energy Management: Features like recirculation controls and Wi‑Fi monitoring enable demand-driven operation and remote diagnostics to lower operating costs.
Installation And Venting
- Indoor vs Outdoor Mounting: Outdoor-rated tankless units (Rinnai CU160eN) minimize indoor venting needs but require weather protection and appropriate clearances.
- Venting Category: Confirm venting category and clearances for unit heaters. Some units support both vertical and horizontal venting to fit site constraints.
- Gas Supply And Piping: Verify gas line sizing for peak BTU demand and ensure proper regulators and conversion kits if changing fuel type.
Reliability, Serviceability, And Lifespan
- Materials And Corrosion Resistance: Commercial tanks with glass-lined interiors and sacrificial anodes (American Standard) extend service life in hard water or aggressive environments.
- Access For Maintenance: Ceiling-mounted or compact units must still allow access for burners, filters, and controls. Factor in service clearances when planning installation.
- Parts Availability: Choose manufacturers with broad service networks and easily sourced replacement parts for quicker turnaround.
Safety And Compliance
- Oxygen Depletion Sensors & Safety Shutoffs: Required on ventless or indoor gas heating appliances; ensure the unit includes necessary safety interlocks.
- Clearances And Code Compliance: Follow local mechanical and fuel gas codes for clearances, vent termination, and combustion air.
- Professional Installation: Commercial gas appliances typically require licensed technicians for safe, code-compliant setup and commissioning.
Comparison Perspectives
- Energy Efficiency Perspective: Condensing tankless units provide the best fuel-to-heat efficiency for water heating, reducing long-term gas consumption.
- Peak Demand Perspective: Large storage tanks handle simultaneous high peaks without needing oversized piping or complex control logic.
- Space And Venting Perspective: Outdoor-mounted tankless units minimize indoor mechanical footprint; ceiling-mounted forced-air heaters reduce floor obstruction in large open spaces.
- Operational Flexibility Perspective: Units with staged firing, recirculation, or Wi‑Fi controls adapt more easily to variable business schedules and can lower operating costs.
Final Selection Checklist
- Confirm required BTU output and, for water heaters, required GPM.
- Verify venting options and available installation location (indoor/outdoor, ceiling/wall).
- Assess fuel type availability and whether conversion kits are needed.
- Review efficiency ratings and features such as recirculation and remote monitoring.
- Plan for maintenance access, local code compliance, and professional installation.