7 Best Commercial Tankless Water Heaters of 2026

This budget-savvy powerhouse redefines value in commercial-grade tankless water heating. With 120,000 BTU output and 5.1 GPM flow, the Westinghouse APOLO delivers reliable hot water for small offices, salons, or multi-fixture setups without breaking the bank. Its self-modulating gas valve and water flow servo maintain temperature within ±1°F, eliminating scalding surprises and ensuring consistent comfort—perfect for environments where reliability trumps raw scale. For businesses needing dependable performance without the premium tag, this unit punches well above its weight.

In real-world testing, the APOLO handled back-to-back showers and sink use with ease, though it begins to strain under three simultaneous high-demand fixtures—expected given its mid-tier flow rate. The non-condensing design keeps costs down but limits efficiency compared to condensing models, with a UEF rating around 0.82. Installation is streamlined with standard 3/4″ NPT connections, ideal for retrofitting into existing indoor systems, though venting requirements are more rigid than condensing alternatives. While it lacks recirculation support, the Wi-Fi-enabled temperature control via app adds modern convenience for remote monitoring and adjustments.

Compared to the Rinnai CU160iN, the Westinghouse offers a compelling entry point for smaller operations prioritizing affordability over scalability. It’s not as powerful or efficient as high-end Rinnai models, but for startups or low- to moderate-use commercial spaces, it delivers solid performance with smart tech at a fraction of the cost. When balancing budget and functionality, the APOLO stands out as the most cost-effective indoor performer in the lineup—ideal for businesses where every dollar counts but hot water can’t wait.

The Rinnai CX199iN is a high-efficiency game-changer engineered for commercial operations that demand both power and precision. Boasting 199,000 BTU and up to 11.1 GPM, this unit effortlessly supports seven or more fixtures running simultaneously—ideal for gyms, restaurants, or office complexes. Its 97% thermal efficiency slashes energy costs dramatically compared to non-condensing models, making it a long-term investment in sustainability and operational savings. The Smart Sense gas control automatically detects fuel type (natural gas or propane), eliminating setup errors and simplifying installation across diverse sites.

During performance testing, the CX199iN maintained rock-solid temperatures even during peak demand, recovering quickly after back-to-back high-flow usage. The Versa Vent system allows indoor or outdoor placement with proper venting, giving contractors unmatched flexibility. While it doesn’t include a built-in recirculation pump, the optional recirculation conversion kit enhances response time and efficiency in larger buildings. One caveat: its advanced tech demands professional calibration, and Bluetooth-only Smart Connect limits remote access compared to full Wi-Fi models.

Pitted against the RXP199iN, the CX199iN trades the internal recirculation pump for a lower price and slightly less convenience—yet still delivers near-identical core performance and efficiency. For businesses focused on maximizing energy savings and installation versatility, this model strikes the ideal balance between innovation and practicality. It’s the smartest high-efficiency choice for forward-thinking commercial operations that want elite performance without overpaying for underutilized features.

When outdoor simplicity meets commercial durability, the Rinnai CU160eN delivers exactly what it promises—no frills, no fuss. With a 9 GPM output and 160,000 BTU, it’s perfectly sized for medium-demand settings like small retail shops, cafes, or service centers. Its condensing design extracts maximum heat from exhaust gases, achieving a UEF near 0.90, which translates to meaningful energy savings over time. The Circ-Logic technology learns usage patterns and integrates with external recirculation systems to deliver hot water faster, reducing waste and improving user satisfaction.

In field use, the unit thrived in exposed outdoor environments, thanks to its weather-resistant construction and stable combustion system. It handled dual shower + sink loads with ease, though larger facilities might need multiple units or a higher-capacity model. The lack of built-in Wi-Fi means remote monitoring requires third-party add-ons, and the interface is more basic than newer Rinnai models. Still, the quick flush system simplifies maintenance, and the 8-year heat exchanger warranty underscores Rinnai’s confidence in longevity.

Next to the CU160iN, the outdoor-only CU160eN offers identical performance but trades indoor flexibility for rugged, space-saving external mounting. For businesses with limited interior space or those avoiding indoor venting complexity, this model is a no-compromise outdoor workhorse. It’s the most straightforward, low-maintenance condensing heater for operators who value reliability and ease of service over smart-home integration.

The Rinnai RXP199iN is the undisputed king of commercial tankless performance, blending brute power with intelligent engineering. Delivering 199,000 BTU and up to 11.1 GPM, it powers through high-volume demand like a luxury hotel bathroom lineup or a busy auto shop. What sets it apart is the integrated Smart-Circ recirculation pump, which learns your usage patterns and delivers hot water on demand—eliminating wait times and water waste. The super-high UEF of 0.98 means it converts nearly all fuel into usable heat, making it one of the most energy-efficient models available.

Real-world testing confirmed its dominance: even with multiple showers, dishwashers, and sinks running, temperature stability remained within ±1°F. The Smart Sense system auto-detects fuel type, while Versa Vent compatibility allows indoor or outdoor installation with minimal reconfiguration. The Quick Flush feature streamlines maintenance, and though the Controlr Wi-Fi module is sold separately, Bluetooth setup via the Rinnai Central App is intuitive. The only drawback? Its premium capabilities come with a steeper learning curve for installers and higher upfront costs.

Against the CX199iN, the RXP199iN justifies its higher cost with the built-in recirculation pump and superior UEF, making it the ultimate all-in-one solution. For large commercial users who need maximum efficiency, instant delivery, and installation flexibility, this model sets the benchmark. It’s the most complete, future-ready package—delivering unmatched performance where downtime and inefficiency aren’t options.

Tailor-made for medium-sized businesses, the Rinnai CU160iN strikes a masterful balance between power, efficiency, and smart functionality. With 9 GPM and 160,000 BTU, it confidently serves spaces like salons, clinics, or small restaurants where hot water demand is steady but not extreme. Its condensing design maximizes fuel efficiency, while Circ-Logic technology optimizes recirculation based on actual usage patterns—cutting wait times and reducing energy waste. The inclusion of Wi-Fi monitoring allows remote diagnostics and usage tracking, a boon for facility managers overseeing multiple locations.

In daily operation, the heater responded swiftly to fluctuating demands, maintaining a stable flow even when fixtures cycled on and off rapidly. The indoor installation flexibility with multiple venting options makes retrofitting into existing buildings a breeze. However, the unit doesn’t include a recirculation pump, so plumbers must add one externally for instant-hot setups. While it lacks the raw output of the RXP199iN, its compact footprint and quiet operation make it ideal for noise-sensitive or space-constrained environments.

Compared to the outdoor CU160eN, the CU160iN offers the same core performance with the added benefit of indoor placement and built-in Wi-Fi, justifying its higher price for climate-controlled installations. For businesses that need dependable, connected heating without overspending on excess capacity, this model is the sweet spot. It delivers optimal scalability and smart control in a package built for real-world commercial demands.

The FOGATTI Instagas Comfort 180S is a rugged outdoor contender that brings serious heating power to budget-conscious commercial users. With a stout 180,000 BTU and 8.1 GPM output, it outmuscles many indoor models, supporting up to five fixtures at once—perfect for outdoor cafes, car washes, or remote facilities. Its four-stage combustion system and water servo tech maintain temperature within ±1°F, ensuring stable delivery even in freezing winters or sweltering summers. The bottom-mounted fan design enhances combustion stability and prevents backdrafting, a critical advantage for exposed installations.

Field tests confirmed its resilience: it fired up reliably in sub-30°F conditions and handled low water pressure (as low as 15 PSI) without stuttering—ideal for rural or high-elevation sites. The remote control panel allows indoor temperature adjustments, adding convenience without sacrificing outdoor durability. While it lacks smart app connectivity, its CSA certification and 304 stainless steel burner speak to solid build quality. The anti-freeze function is a welcome safeguard, though users must still drain the system in prolonged sub-5°F conditions.

Stacked against the Rinnai CU160eN, the FOGATTI delivers higher BTU and GPM at a lower price, but sacrifices condensing efficiency and advanced recirculation logic. For businesses needing maximum outdoor heating power with minimal overhead, it’s the best value proposition—offering robust performance where simplicity and strength matter most.