Best Tankless Water Heaters: 5 Editor’s Picks for Every Home & Climate
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If you’re moving to tankless, three things matter most: right-size flow (GPM) for your climate’s temperature rise, venting/installation fit (PVC vs. stainless, indoor vs. outdoor), and a warranty you can live with. I picked five strong, widely available models that balance output, efficiency, and long-term support.
How I researched
I compared 2025 spec sheets/manuals and reputable testing write-ups, prioritized whole-home flow at a 60–70°F rise (colder-climate reality), verified UEF/efficiency, venting, minimum activation flow, certifications, and residential warranty terms, and noted recirculation options and electrical load for electric units. I weighed flow stability, efficiency (UEF), ease of venting/recirc, and ownership costs/durability (heat-exchanger materials, support).
Top picks
Rinnai RU199iN — Best for most gas homes (indoor, natural gas)
A high-efficiency, 199k BTU condensing unit that reliably covers multi-bath homes in cold climates.
Why it wins: Excellent efficiency and broad 15k–199k BTU modulation deliver steady hot water; recirc-ready via Circ-Logic if you add a pump.
- Endless Hot Water: Our tankless hot water heaters offer unlimited whole-home hot water flow and come equipped with Circ-Logic for pairing with an external pump to reduce wait time for hot water via scheduled or on-demand recirculation
- Energy and Space Efficient: The tankless design of this small hot water heater saves on space and conserves energy as it heats only when necessary
- Optimal Water Pressure: With a hot water flow rate of up to 11 GPM, this tankless water heater provides a powerful, constant stream that can accommodate up to 7 appliances at once
Pros
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High UEF with cold-climate output
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Wide modulation steadies temps across seasons
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Compact “suitcase” footprint for indoor install
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Large pro support network
Cons
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No built-in pump; add-on for recirc
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Wi-Fi control requires an accessory
Social proof
Strong owner sentiment on performance and build; see reviews on Amazon.
Trade-offs / Who should skip
If you want built-in recirculation, Rinnai’s RUR line or similar “A-series” models fit better; otherwise this is the sweet spot for efficiency and output.
Scores: Performance 4.8/5 · Flow rate 4.8/5 · Ease of Use 4.5/5 · Value 4.6/5
Rheem RTGH-95DVLN-3 — Best for easy PVC venting and compact depth
A super-efficient 9.5 GPM condensing model with simple venting and a slim 9.8-inch depth.
Why it wins: Strong efficiency, long PVC/CPVC/PP vent options, and a clear 15/5/1 warranty from a familiar brand.
- Flow rate of 0.4 - 9.5 GPM
- Available temperature settings range from 100 to 140F (default setting of 120F)
- Includes electric ignition
Pros
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Condensing efficiency with ENERGY STAR class performance
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Long vent runs with common materials
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Slim depth helps tight mechanical spaces
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Low activation flow helps low-flow fixtures
Cons
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Max flow a notch below 11 GPM units
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Wi-Fi/recirc add-ons cost extra
Social proof
Broad homeowner adoption and easy installs; see reviews on Amazon.
Trade-offs / Who should skip
Great for remodels needing long PVC runs. If you need built-in recirculation, pick a unit with an integrated pump.
Scores: Performance 4.6/5 · Flow rate 4.4/5 · Ease of Use 4.6/5 · Value 4.6/5
Noritz NRC661-DV-NG — Best compact condensing for 1–2 baths
A 120k BTU indoor, direct-vent condensing unit that’s efficient and space-savvy.
Why it wins: Solid 12/5/1 warranty and compact size make it a smart downsized pick where ~6.6 GPM fits.
- Endless hot water
- Can be vented with Schedule 40 PVC Pipe and Fitting
- High Efficiency
Pros
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Efficient condensing, PVC-vent friendly
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12-year heat-exchanger warranty
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Compact for closets and utility rooms
Cons
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6.6 GPM suits smaller homes
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Hard water may require treatment
Social proof
Praised for compact installs and reliability; see reviews on Amazon.
Trade-offs / Who should skip
If you run two showers plus laundry in cold climates, size up to a 180–199k BTU model.
Scores: Performance 4.2/5 · Flow rate 3.9/5 · Ease of Use 4.5/5 · Value 4.6/5
Stiebel Eltron Tempra 24 Plus — Best electric whole-home (warm climates)
A 24 kW, UL-listed electric unit with Advanced Flow Control that throttles flow to maintain set temperature.
Why it wins: No venting, 99% electric conversion, and proven reliability—great where gas/venting is impractical. Requires 2×50A breakers (240 V).
- Digital temperature control. Voltage : 240 Volt or 208 Volt
- Proven reliability
- No venting required
Pros
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Vent-free; indoor install almost anywhere
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Advanced Flow Control aids temp stability
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UL-listed; straightforward maintenance
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Quiet operation
Cons
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Heavy electrical load; panel upgrades likely
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Lower GPM in cold-water regions
Social proof
Well-reviewed for simplicity and reliability; see reviews on Amazon.
Trade-offs / Who should skip
If incoming water is very cold or your home needs >3–4 GPM at a high rise, a 199k BTU gas model will outperform.
Scores: Performance 4.0/5 · Electrical load 3.5/5 · Ease of Use 4.7/5 · Value 4.4/5
Takagi T-H3-DV-N — Best value 199k BTU workhorse
A fully condensing, Ultra-Low NOx 199k BTU indoor unit with a robust heat-exchanger design.
Why it wins: High output with a 15/5/1 warranty; proven platform that’s service-friendly and altitude-rated.
- Endless hot water, On-demand usage, Compact, Space saving, Energy conservation
- Computerized safety features, No pilot light to have to worry about
- Safety features include freeze, overheat, surge protection, and troubleshooting diagnostic codes
Pros
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High output for multi-bath homes
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Ultra-Low NOx compliant
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Solid 15/5/1 warranty
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Broad parts availability
Cons
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App/Wi-Fi control not standard
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Recirc requires external components
Social proof
Popular with pros for durability and serviceability; see reviews on Amazon.
Trade-offs / Who should skip
If you want native recirculation hardware, consider an “A/RUR” style model instead.
Scores: Performance 4.6/5 · Flow rate 4.6/5 · Ease of Use 4.3/5 · Value 4.7/5
Quick compare
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Rinnai RU199iN — Best for most gas homes: High efficiency, strong cold-climate flow; add pump for recirc.
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Rheem RTGH-95DVLN-3 — Best for easy PVC venting: Long PVC runs, compact depth; 9.5 GPM class.
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Noritz NRC661-DV-NG — Best compact 1–2 bath: Condensing, smaller footprint; best for modest demand.
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Stiebel Tempra 24 Plus — Best electric whole-home: No venting, 2×50A breakers; best for warmer climates.
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Takagi T-H3-DV-N — Best value 199k workhorse: High output, ULNox compliant; add-on recirc.
Buying guide
1) Size for your climate and fixtures
Tankless output depends on temperature rise and flow. In cold-water regions (≈60–70°F rise), a 199k BTU condensing unit is the safe pick for two showers plus a sink; 9–10 GPM models match many 2-bath homes. Check the GPM vs. rise charts before you buy.
2) Condensing = simpler venting
Condensing gas units exhaust cooler flue gas so you can often use Schedule-40 PVC, CPVC, or polypropylene with long runs. That can save install complexity vs. non-condensing stainless venting.
3) Recirculation—nice to have
If short wait times matter, choose models with built-in recirc or ensure the unit supports external pumps and scheduled recirc (e.g., Circ-Logic). Built-in buffers help reduce “cold-water sandwich.”
4) Water quality matters
Many warranties exclude scale damage above certain hardness. If you’re in hard-water territory, budget for treatment and annual flushes.
5) Electric vs. gas
Electric is vent-free and highly efficient but requires substantial service (Tempra 24 Plus needs 2×50A at 240 V). In cold climates or high-demand homes, gas condensing usually delivers more usable GPM.
6) Warranty & support
Typical residential coverage is around 15 years on the heat exchanger, 5 years on parts, and 1 year on labor for top gas brands. Register your unit and follow water-quality/installation requirements.
7) Incentives
ENERGY STAR-certified gas tankless units may qualify for federal credits or local rebates—check your specific model and utility.
FAQs
Q: What size should I pick for a 2-bath home in a cold climate?
A: Look at the 70°F rise row in the manufacturer’s chart. If you need ~5–6 GPM simultaneous, a 180–199k BTU condensing unit is safer than mid-range models.
Q: Can I vent with PVC?
A: Most condensing gas models allow PVC/CPVC/PP with specific length/elbow limits. Always follow the installation manual.
Q: Do I need a dedicated recirculation line?
A: Some systems use a dedicated return; others use crossover valves at the far fixture. Models with built-in recirc make this easier; others support scheduled recirc with an external pump.
Q: What about warranties?
A: Typical formats are 15 years (heat exchanger) / 5 years (parts) / 1 year (labor) for residential gas tankless. Electric warranties vary; confirm your manual and register the unit.
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