Best Commercial Tankless Hot Water Heaters for Businesses and Buildings
For facilities that demand reliable, scalable hot water with minimal energy waste, commercial tankless units offer on-demand performance, compact footprints, and flexible installation. This guide highlights five top options from trusted brands, focusing on flow rates, fuel type, and advanced controls. Compare units below to identify the best fit for restaurants, offices, multi-bath installations, or industrial spaces.
Selected products overview (summary table)
| Product | Brand | Flow (GPM) | BTU | Fuel | Key Feature |
|---|---|---|---|---|---|
| A. O. Smith Tankless Water Heater | A. O. Smith | Up to 10.0 | 199,000 | Natural Gas / Propane | X3 Scale Prevention Technology |
| NEW Rinnai RX199iN | Rinnai | Up to 11.1 | 199,000 | Natural Gas / Propane | |
| Rinnai CX199iN | Rinnai | Up to 11.1 | 199,000 | Natural Gas / Propane | |
| Westinghouse APOLO Outdoor | Westinghouse | Up to 8.1 | 180,000 | Natural Gas / Propane | |
| APUS 190,000 BTU Outdoor | APUS | Up to 8.1 | 190,000 | Natural Gas |
A. O. Smith Tankless Water Heater
A. O. Smith ProLine XE tankless unit delivers continuous hot water with a high-capacity input of 199,000 BTU and a practical flow rate up to 10.0 GPM. This model features X3 Scale Prevention to minimize mineral buildup and a copper heat exchanger noted for rapid, stable temperature performance. It is easily converted between natural gas and propane, enabling flexible installation across commercial settings. The unit supports high efficiency operation with a Uniform Energy Factor (UEF) up to 0.81, helping reduce ongoing energy costs in busy commercial environments.
Key points: compact indoor footprint, robust heat exchanger material, flexible fuel conversion, and scalable output for small to mid-size commercial applications.
NEW Rinnai RX199iN Condensing Tankless Water Heater
This versatile model supports indoor or outdoor installation with Versa Vent and both natural gas and propane compatibility through a Smart Sense control system. With up to 11.1 GPM and 199,000 BTU, it provides ample capacity for multiple fixtures concurrently. The RX199iN emphasizes energy efficiency with a high UEF of 0.98 and offers a Quick Flush feature for maintenance. A WiFi-ready controller (ControlR) enables remote monitoring and adjustments, though the module is sold separately.
Key points: flexible installation, high efficiency, smart features, and robust performance for medium-to-large commercial loads.
Rinnai CX199iN Condensing Water Heater
Rinnai CX199iN combines commercial-grade efficiency with installation flexibility. Its 199,000 BTU input allows up to 11.1 GPM, supporting multiple outlets simultaneously. The unit uses a Smart Sense gas control system and Versa Vent compatibility for both propane and natural gas, with an optional conversion kit for recirculation. With a thermal efficiency of 97%, it emphasizes lower energy costs. Outdoor-ready configurations are practical for businesses seeking streamlined ventilation and versatile placement.
Key points: high efficiency, versatile installation, and energy-conscious operation suitable for commercial use with or without recirculation upgrades.
Westinghouse APOLO Outdoor Natural Gas Tankless
The APOLO Outdoor model delivers up to 8.1 GPM with 180,000 BTU, designed for outdoor installation and remote operation to manage temperature precisely. Its self-modulating gas system helps maintain consistent water temperatures with a ±1°F variance, supporting 3–5 fixtures simultaneously. This unit is well-suited for outdoor kitchens, small commercial facilities, and multi-outlet applications where weatherproofing and outdoor placement are advantageous.
Key points: outdoor-ready, precise temperature control, and strong simultaneous-use capacity for mid-sized commercial needs.
APUS 190,000 BTU Outdoor Tankless Water Heater
APUS offers a robust outdoor tankless solution at 190,000 BTU with a maximum flow of 8.1 GPM. It emphasizes smart control through WiFi and a remote control option, delivering precise on-demand heating with a stability of ±1°F. The unit is designed for whole-house performance and can support multiple outlets while maintaining efficiency. Its 0.79 GPM minimum flow helps ensure reliable operation even with lower water pressure in commercial installations.
Key points: outdoor-ready design, smart control integration, and reliable performance under varied demand scenarios.
Buying Guide: Key Purchase Considerations
- Flow requirements: Assess peak simultaneous usage. Commercial settings often require 8–12+ GPM; select units rated for that range or higher to avoid cold-water sandwiching and short cycling.
- Fuel type and availability: Natural gas is common in commercial spaces, but propane can provide flexibility where gas lines are limited. Consider conversion options if fuel sources may change.
- Ventilation and installation: Condensing models typically require venting; determine indoor vs outdoor installation, space constraints, and venting compatibility (Versa Vent systems are common in modern units).
- Efficiency and operating cost: Look for high UEF/thermal efficiency figures and features like modulation, quick flush, and min/max flow controls to optimize energy use and equipment lifespan.
- Maintenance and serviceability: Choose units with accessible maintenance features (flush capabilities) and widely available service networks for commercial properties.
- Remote monitoring and controls: WiFi or app-based controls enable centralized management across multiple units, helpful for facilities with distributed hot water needs.
- Installation flexibility: Consider models with outdoor options, compact footprints, and compatibility with optional recirculation kits to improve hot water delivery times.
- Durability and warranties: Commercial-grade units often come with extended warranties; confirm coverage for parts and labor in your region and for continuous operation scenarios.
When selecting a commercial tankless water heater, balance peak demand against installation realities, maintenance capabilities, and total cost of ownership. The models above provide a spectrum of capacities, fuels, and control options designed to meet various business needs while prioritizing efficiency and reliability.