Struggling with endless showers and high heating bills? A combination tankless water heater and boiler solves both.
A combination unit provides endless hot water and home heating. Top options like the Rheem RTG-70XLN-3 deliver high efficiency. This dual function saves significant space and energy.
The Rheem RTG-70XLN-3 is built for outdoor installation. The Rheem Natural Gas Condensing model offers superior indoor efficiency. The Rheem RTGH Series provides powerful propane performance. Each simplifies your home’s mechanical systems.
We break down flow rates, installation needs, and operating costs to help you choose the right model for your home.
Rheem Tankless Natural Gas Heater
For homeowners seeking the best combination tankless water heater and boiler for reliable, high-volume hot water, the Rheem RTG-70XLN-3 is a formidable outdoor contender. This high-efficiency natural gas unit is engineered to handle the simultaneous demands of a 2–3 bathroom home without breaking a sweat.
Pros
The standout feature is its impressive 7.0 gallons-per-minute flow rate, powered by 160,000 BTUs, which genuinely delivers on its promise of consistent hot water during peak usage—no more negotiating shower schedules. The hot-start programming is a genius touch that eliminates those shocking cold water bursts between back-to-back uses. Its outdoor design and durable metal cabinet free up valuable space and simplify installation for a qualified professional.
Cons
The primary consideration is the required professional installation; this isn’t a DIY project due to the gas and venting requirements, which adds to the upfront cost. As a non-condensing model, it operates with slightly lower efficiency than premium condensing units, though its performance remains robust. The outdoor placement means it must be factored into your home’s exterior layout.
Positioned at number one in our ranking for its category, this Rheem model excels as a workhorse solution. It provides dependable, high-volume hot water with smart features that address common tankless frustrations, making it an excellent investment for larger households.
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Rheem Natural Gas Tankless Water Heater
Tired of running out of hot water during a shower while your home heating system struggles? The Rheem Natural Gas Condensing Tankless Water Heater fixes it with a high-efficiency, dual-purpose design that provides endless hot water and supports your boiler.
Why It Works
- High 9 GPM flow rate solves the problem of insufficient hot water for simultaneous use in multiple bathrooms.
- Condensing technology and 180,000 BTU output directly address high utility bills by maximizing fuel efficiency for both hot water and space heating support.
- Precise 100-140°F temperature control prevents the issue of scalding or lukewarm water, ensuring consistent delivery.
Trade-offs
- Requires professional installation, adding upfront cost, but is essential for safe integration with existing gas and venting systems.
- The high BTU rating demands adequate gas line capacity, a potential upgrade, yet this is what enables its superior whole-home performance.
With its robust 15-year warranty on the heat exchanger, this unit is worth it for homeowners seeking a reliable, integrated solution for domestic hot water and hydronic heating support.
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Rheem RTGH 9.5 GPM Tankless Heater
The Rheem RTGH 9.5 GPM Tankless Heater: 17-11/16-in wide, stainless steel heat exchanger, with a 15-year warranty on the heat exchanger and a 5-year warranty on parts.
Benefits
- Its high 199,900 BTU input supports a flow rate up to 9.5 gallons per minute, capable of supplying multiple fixtures simultaneously in most homes.
- The unit provides precise temperature control, with adjustable settings from 100 to 140 degrees Fahrenheit for customized comfort.
- Its compact, indoor design and straightforward electric ignition make for a relatively simple installation process for a qualified professional.
Drawbacks
- The system requires a 120-volt electrical connection, adding complexity compared to purely gas-fired models.
- At lower flow rates below 0.4 GPM, the heater may not activate, which could lead to lukewarm water during very low-demand use.
- The labor coverage is limited to one year, while competing models sometimes offer longer periods.
A practical pick for homeowners seeking a powerful, combination-style unit for whole-house propane applications where electrical access is available at the installation point.
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Rheem 9.5 GPM Gas Tankless Heater
The Rheem RTGH-95DVLN-3 is a powerful indoor gas unit designed to provide endless hot water while also functioning as a best combination tankless water heater and boiler for space heating applications. Ideal for larger homes with 2-3 bathrooms, its 199,900 BTU output and 9.5 GPM flow rate ensure consistent performance. The compact stainless steel construction saves valuable space compared to a traditional tank.
This model excels by solving the problem of running out of hot water during simultaneous showers. Its high efficiency directly translates to lower energy bills. The integrated controller allows precise temperature adjustments from 100°F to 140°F, offering customized comfort for every tap in your home.
Pros
- Dual-function capability efficiently handles both domestic hot water and hydronic heating needs.
- Substantial flow rate supports multiple fixtures running at once without a temperature drop.
- Industry-leading warranty, including a 15-year coverage on the heat exchanger, promises long-term reliability.
- Space-saving design frees up floor area where a bulky tank heater would normally sit.
- Precise temperature control via the digital interface prevents scalding and ensures comfort.
Cons
- The high BTU requirement may necessitate an upgrade to your existing gas line, adding to installation cost.
- As an indoor-only model, it requires proper venting, limiting placement flexibility compared to outdoor units.
In real-world use, the Rheem RTGH-95DVLN-3 delivers robust, on-demand hot water. Its standout feature is truly its versatility as a combo unit, making it a superb value for homeowners seeking to consolidate their heating systems. It’s best suited for those with a sufficient gas supply who want to eliminate the wait for hot water forever. The minor drawbacks are primarily upfront installation considerations that are well worth the long-term benefits of endless hot water and efficient heating.
The value proposition is strong due to its dual functionality and impressive warranty. This unit is the ideal choice for a homeowner ready to upgrade their entire home’s hot water and space heating with one efficient, high-performance system.
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Rinnai RX199iN Tankless Water Heater
If you’re looking for the best combination tankless water heater and boiler for whole-home comfort, the Rinnai RX199iN is a remarkably versatile contender that deserves your attention.
Pros
- The installation flexibility is outstanding; one model works indoors or outdoors and can run on either propane or natural gas.
- It delivers a powerful up to 11.1 gallons per minute of hot water, easily handling multiple fixtures at once.
- The condensing design achieves an impressive .98 energy efficiency factor, which will save on utility bills.
- Features like the Quick Flush system make long-term maintenance much simpler for technicians.
Cons
- Professional installation is strongly recommended, which adds to the upfront project cost.
- The required Controlr module for WiFi connectivity is sold separately, which feels like an extra step.
- You must check your local groundwater temperature to ensure it can reach its full potential in your climate.
For homes needing serious hot water output without sacrificing efficiency or placement options, this Rinnai model makes a compelling and smart investment.
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FAQ about the best combination tankless water heater and boiler:
1: What is a combination tankless water heater and boiler?
A combination unit, or combi-boiler, integrates a high-efficiency tankless water heater with a central heating boiler into one compact appliance. It provides on-demand domestic hot water and hydronic heating for radiators or underfloor systems.
2: What are the primary advantages of a combi-boiler system?
Key benefits include exceptional space savings, superior energy efficiency from eliminating standby heat loss, and an unlimited supply of hot water. These systems offer a consolidated solution for residential heating and water needs.
3: How do I select the best combination unit for my home?
Selection criteria necessitate evaluating your home’s peak hot water demand (flow rate in GPM) and total heating load (BTU requirement). Prioritize units with high modulation ratios for efficiency and confirm compatibility with your existing heating distribution system.
4: Are there specific installation considerations for combi-boilers?
Professional installation is imperative. Critical factors include adequate gas line sizing, proper venting configuration, and water quality, as hard water may necessitate a scale inhibition system to protect the heat exchanger.
Conclusion
The Rheem RTG-70XLN-3 offers a robust, weatherproof solution for high-volume demand, prioritizing straightforward installation and proven reliability. Its substantial flow rate capably serves multiple fixtures, establishing it as a formidable standalone unit for comprehensive hot water delivery.
For ultimate efficiency and performance, the condensing indoor model presents a superior thermal conversion, yielding greater output with reduced energy expenditure. This advanced system represents the pinnacle of integrated heating technology, providing an unparalleled solution for simultaneous domestic and space heating requirements.
