For a whole-home gas water heater, the Rheem RTG-95DVLN-3 is my best overall pick in this lineup because its 9.5 GPM capacity suits higher simultaneous demand better than the smaller indoor units. The Rheem RTG-70XLN-3 stands out for outdoor natural gas installation, while the CAMPLUX AY132G is a portable propane option for outdoor tasks and trips. The key tradeoff is between household flow and installation requirements on one side, and compact portability with lower output on the other. Fuel type, venting, climate, and the number of fixtures in use all affect whether a model will fit. Read on for the full comparison, buying criteria, and guidance by buyer type.
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Key Takeaways
The Rheem RTG-95DVLN-3 has the lineup’s stated 9.5 GPM capacity, making it the strongest fit for homes with overlapping hot-water demand; it still needs a compatible indoor installation.
Outdoor natural gas models such as the Rheem RTG-70XLN-3 avoid indoor vent routing, but their location must suit local weather and installation rules.
The indoor QERPRE and Novieex share 100,000 BTU and 4.3 GPM specifications, so buyers should compare installation requirements, support, and documentation rather than assume the headline capacity separates them.
Portable propane units from CAMPLUX and other compact listings trade household-level flow for mobility; their stated capacities are better suited to limited, outdoor hot-water tasks.
The product list spans natural gas and propane, indoor and outdoor mounting, and capacities from about 1.3 to 9.5 GPM, so choosing by fuel and site compatibility first narrows the field faster than comparing BTU alone.
| gas water heater | Fuel | Flow rate | Heat output |
|---|---|---|---|
| Rheem RTG-70XLN-3 Outdoor Natu | Natural gas | — | — |
| Propane Tankless Water Heater | Propane | 4.76 GPM | — |
| Tankless Propane Gas Water Hea | Propane gas | 2.11 GPM | 40,824 BTU |
| QERPRE Tankless Water Heater N | Natural gas | — | — |
| Novieex Natural Gas Tankless W | Natural gas | 4.3 GPM | — |
| Outdoor Propane Tankless Water | Propane | 1.58 GPM | 40,000 BTU/hr |
| Rheem RTG-95DVLN-3 Indoor Natu | Natural gas | 9.5 GPM at 35°F temperature rise | 199,900 BTU/hr |
| CAMPLUX AY132G Portable 5L Pro | Propane | 1.32 GPM | 34,000 BTU |
| ThermoMate CZ422NG Natural Gas | Natural gas | Up to 5 GPM | 113,000 BTU |
| Rheem RTG Series 8.4 GPM Natur | Natural gas | 8.4 GPM at 35°F temperature rise | 180,000 BTU/hr |
| APUS Natural Gas Tankless Wate | Natural gas | 4.42 GPM | 95,000 BTU |
| VEVOR Indoor Gas Tankless Wate | — | 16 L/min (about 4.2 GPM) | 100,000 BTU |
| Indoor Propane Tankless Water | Propane (LPG) | — | 68,000 BTU per hour |
| Rheem RTG Series 7.0 GPM Natur | Natural gas | 7.0 GPM | 160,000 BTU/hr |
| CAMPLUX AY132 Portable Tankles | Propane | 1.32 GPM | 34,000 BTU |
More Details on Our Top Picks
Rheem RTG-70XLN-3 Outdoor Natural Gas Tankless Water Heater, 7.0 GPM, 160,000 BTU
The Rheem RTG-70XLN-3 is the strongest fit here for households that want natural gas and a higher flow rate: its stated 7.0 GPM at a 35°F rise gives it more capacity than the 4.3 GPM QERPRE and Novieex indoor units. That can make a difference when several fixtures draw hot water, though actual output depends on incoming water temperature and installation conditions. Its outdoor, non-condensing design avoids indoor vent routing, while Hot Start Programming is intended to reduce cold bursts between uses. The tradeoff is placement: the unit must be installed outside, and professional installation is required. I would choose it over the compact propane heaters for a permanently installed, higher-demand home, but skip it if outdoor exposure or the available mounting location is a problem.
Pros:- 7.0 GPM stated flow rate offers more capacity than the 4.3 GPM indoor models in this batch.
- Outdoor installation avoids routing a flue through the home.
- Hot Start Programming is designed to reduce cold bursts between uses.
- Freeze, flame-failure, and overheat protections are specified.
Cons:- Outdoor-only placement can limit installation options and expose the unit to local weather conditions.
- Professional installation is required.
- The stated flow rate is tied to a 35°F temperature rise, so colder incoming water can reduce available flow.
Best for: Households with natural gas service seeking a higher-capacity, permanently mounted outdoor heater for multiple hot-water uses.
Not ideal for: Buyers who need an indoor unit, portable hot water, or a location without a suitable outdoor mounting spot.
- Model:RTG-70XLN-3
- Fuel:Natural gas
- Installation:Outdoor, wall-mounted
- Type:Non-condensing tankless
- Maximum flow rate:7.0 GPM at a 35°F temperature rise
- Maximum output:160,000 BTU/hr
- Uniform Energy Factor:0.82
- Temperature control:Digital LED panel; ±1°F adjustments
- Warranty:15-year heat exchanger; 5-year parts
Our verdict“Choose the Rheem for a higher-demand home with a suitable outdoor location and natural gas service.”
Propane Tankless Water Heater with Digital Display (4.76 GPM, 115,425 BTU)
This propane tankless heater suits buyers who need hot water at a campsite, RV, or outdoor bathing setup rather than a fixed whole-home installation. Its stated 4.76 GPM is more than the 2.11 GPM listed for the smaller 8L Tankless Propane Gas Water Heater, giving it more headroom for outdoor tasks. A digital display and adjustable temperature setting make operation more direct, and the listed protections cover issues including flame failure and low-flow ignition lockout. That flexibility comes with setup demands: it requires a propane supply and outdoor ventilation, and its outdoor-only design rules it out as an indoor household replacement. Compared with the Rheem RTG-70XLN-3, it is easier to situate for temporary use but offers a lower stated flow rate and is not aimed at permanent whole-home service.
Pros:- 4.76 GPM stated flow rate exceeds the 2.11 GPM rating of the 8L portable model.
- Digital display and adjustable temperature setting aid operation.
- Six listed protections include flame-failure cutoff and high-pressure relief.
- Compact design suits outdoor and travel use.
Cons:- Outdoor use only; it is not specified for indoor installation.
- Requires a propane tank and suitable ventilation.
- Its portable format is less suited to a permanent whole-home installation than the Rheem natural gas unit.
Best for: Campers, RV owners, and outdoor bath setups that need portable hot water and already have a suitable propane supply.
Not ideal for: Homeowners seeking an indoor, permanently installed whole-house heater or buyers without a safe outdoor setup and propane tank.
- Capacity:18 L
- Heating power:115,425 BTU/hour
- Flow rate:4.76 GPM
- Temperature range:17°F–113°F
- Fuel:Propane
- Display:Digital
- Installation:Outdoor use
- Safety features:Overheat, dry combustion, antifreeze, low-flow ignition lockout, flame-failure cutoff, high water pressure relief
Our verdict“Pick this model for portable outdoor hot water when propane is available and a 4.76 GPM rating fits your needs.”
Tankless Propane Gas Water Heater 8L 2.11 GPM
At a stated 2.11 GPM, this 8L propane heater prioritizes compact carry and light-duty outdoor hot water over running several fixtures. That lower capacity gives it a distinct role beside the 4.76 GPM portable propane model: the larger unit is the better fit when you want more flow, while this one makes more sense when small size and simple transport matter more. Its 40,824 BTU output and six listed protections support basic camping or RV use, but the limited flow is a real constraint for simultaneous draws. The supplied information also does not establish that it is suitable for indoor installation; ventilation may be needed, and a propane tank is not included. I would treat it as a focused portable option, not a substitute for the 4.3 GPM QERPRE or Novieex home units.
Pros:- Compact 8L format is suited to carrying and storage.
- Propane fuel supports portable outdoor setups.
- Six listed protections include overheat, antifreeze, and flame-fault protection.
- 40,824 BTU output is specified for its light-duty use.
Cons:- 2.11 GPM limits simultaneous hot-water use.
- Propane tank is not included.
- Indoor use may require ventilation and is not clearly established by the supplied product details.
Best for: Solo campers or RV users who need a compact propane heater for one modest outdoor hot-water draw at a time.
Not ideal for: Families, multi-fixture households, or anyone who needs higher flow or a clearly specified indoor installation.
- Fuel:Propane gas
- Capacity:8 L
- Heat output:40,824 BTU
- Flow rate:2.11 GPM
- Maximum temperature:113°F
- Dimensions:11.4 in W × 22 in H
- Safety features:Overheat, dry combustion, antifreeze, low-flow, flame-fault, high water pressure protection
Our verdict“Choose this compact model for light outdoor use when portability matters more than flow capacity.”
QERPRE Tankless Water Heater Natural Gas, Indoor, 100,000 BTU, 4.3 GPM
The QERPRE indoor natural gas heater is a practical fit for buyers who want a fixed indoor unit with temperature controls designed to hold steady. Its stated ±1°F stability and modes for kitchen, bathtub, and seasonal settings offer more operating guidance than the basic specifications provided for the Novieex, which shares its 4.3 GPM rating and 100,000 BTU output. The included vent pipe may simplify sourcing the listed accessory, but it does not remove the need for correct gas and vent installation by a professional. At 4.3 GPM, this is a more modest household option than the 7.0 GPM Rheem outdoor model, and the supplied details caution against use above 2,000 feet. I would favor it when indoor placement and its control modes fit the home; skip it if altitude or higher simultaneous demand is a concern.
Pros:- ±1°F stated temperature stability supports steadier hot-water delivery.
- Kitchen, bathtub, and seasonal modes offer control options.
- Vent pipe is included.
- Compact dimensions and a stated 3.6–110 PSI operating range allow flexible placement conditions.
Cons:- Professional installation is required for gas and venting.
- Not recommended above 2,000 feet.
- Its 4.3 GPM maximum is below the Rheem RTG-70XLN-3’s stated 7.0 GPM.
Best for: Households with natural gas that want an indoor tankless unit with adjustable modes and stated ±1°F temperature stability.
Not ideal for: Homes above 2,000 feet elevation, buyers needing the higher stated flow of the Rheem 7.0 GPM unit, or anyone unable to arrange professional venting and gas installation.
- Fuel:Natural gas
- Installation:Indoor
- Maximum flow rate:4.3 GPM
- Temperature stability:±1°F
- Dimensions:22 in H × 14 in L × 6.5 in W
- Water pressure range:3.6–110 PSI
- Fittings:1/2 in NPT
- Included accessory:Vent pipe
Our verdict“Choose the QERPRE for an indoor natural gas installation where steady temperature control matters and elevation is within its stated limit.”
Novieex Natural Gas Tankless Water Heater, 100,000 BTU, 4.3 GPM, Indoor
The Novieex indoor natural gas heater pairs a wall-mounted form with a stated 4.3 GPM flow rate, making it a space-conscious option for homes replacing a bulky tank. Its 100,000 BTU output matches the QERPRE, so the choice between them is less about headline capacity and more about the supplied details: Novieex lists a 95°F–149°F temperature range, a 1.5–116 psi pressure range, and a one-year warranty, while QERPRE specifies ±1°F stability, preset use modes, and an included vent pipe. The Novieex description claims support for multiple fixtures, but actual simultaneous flow depends on temperature rise and plumbing conditions. Professional installation is required, and the product data also flags altitude above 2,000 feet as a limitation. I would shortlist it for space saving, while buyers who prioritize defined controls may prefer QERPRE.
Pros:- Wall-mounted design frees floor space compared with a traditional tank.
- 4.3 GPM stated flow rate and 100,000 BTU output are suited to moderate household demand.
- Temperature range is specified from 95°F to 149°F.
- Listed pressure range begins at 1.5 psi.
Cons:- Professional installation by a licensed technician is required.
- One-year warranty is specified.
- Performance may be limited above 2,000 feet, and the listing provides no flow rating at a defined temperature rise.
Best for: Homeowners replacing a tank who have natural gas service and want a compact, wall-mounted indoor unit.
Not ideal for: Buyers needing a longer specified warranty, homes above 2,000 feet, or shoppers who prefer the QERPRE’s stated temperature stability and included vent pipe.
- Fuel:Natural gas
- Installation:Indoor, wall-mounted
- Flow rate:4.3 GPM
- Power output:100,000 BTU
- Power supply:110–120V AC, 60Hz
- Water pressure range:1.5–116 psi
- Temperature range:95°F–149°F
- Connection size:1/2 in NPT
- Warranty:1 year
Our verdict“Choose Novieex when compact indoor placement is the priority and its stated capacity suits your household demand.”
Outdoor Propane Tankless Water Heater – 6L 1.58 GPM Portable Gas Water Heater with Handle & Overheating Protection
Low-pressure operation sets this portable heater apart: its stated minimum is 2.5 PSI, below the CAMPLUX AY132G’s 3.0 PSI threshold. That can make it a better fit for a gravity-fed setup, though actual performance still depends on the water source. At 1.58 GPM and 40,000 BTU/hr, it offers more flow than the CAMPLUX’s 1.32 GPM, but neither is intended to supply several household fixtures at once. The 12-pound body, foldable handle, and included shower and gas connections favor campsites and cabins where equipment needs to pack away. Its tradeoffs are real: it is not weather-resistant, and the low-pressure specification does not remove the need for safe, correct gas installation. Choose it for occasional outdoor hot water, not permanent exposed installation.
Pros:- 2.5 PSI minimum water pressure is lower than the CAMPLUX AY132G’s stated 3.0 PSI
- 1.58 GPM flow exceeds the CAMPLUX AY132G’s 1.32 GPM
- 12-pound portable body with foldable handle
- Includes shower head, regulator, and hose adapter
Cons:- Not weather-resistant, so it needs protection from rain and prolonged exposure
- Limited flow suits a single outdoor outlet better than household demand
- Incorrect gas connections can create serious installation hazards
Best for: Campers and cabin owners with a low-pressure water source who want a portable shower setup and can keep the heater sheltered.
Not ideal for: Buyers seeking a permanent outdoor installation or enough flow for simultaneous household fixtures; the unit is not weather-resistant and its output is limited.
- Fuel:Propane
- Flow rate:1.58 GPM
- Heat output:40,000 BTU/hr
- Capacity:6 L
- Minimum water pressure:2.5 PSI
- Ignition:Electronic, powered by two D-cell batteries
- Dimensions:11.8 × 5.3 × 17.3 in
- Weight:12 lb
- Safety certification:CSA approved
Our verdict“Pick this for a sheltered campsite or cabin shower where low-pressure compatibility and portability matter more than whole-home output.”
Rheem RTG-95DVLN-3 Indoor Natural Gas Tankless Water Heater, 9.5 GPM
9.5 GPM at a 35°F rise gives this indoor Rheem the largest stated flow in this batch, making it the strongest fit here for homes with several hot-water draws. The outdoor Rheem RTG-84XLN-3 is easier to place when indoor venting is a concern, but its 8.4 GPM capacity is lower; this model trades that placement flexibility for indoor installation and greater stated flow. Hot Start Programming is intended to reduce cold bursts between uses, while freeze and flame-failure protections add useful safeguards. Its 0.82 UEF is a listed efficiency measure, not a reason to assume it will outperform every alternative on operating costs. Professional installation and a direct-vent setup add complexity, so this is a better match for a planned whole-home installation than a simple replacement anyone can mount themselves.
Pros:- Highest stated flow in this batch at 9.5 GPM and a 35°F rise
- Hot Start Programming is designed to reduce cold bursts between uses
- Wall-mounted form saves floor space
- Includes freeze and flame-failure protection
Cons:- Requires professional installation and indoor direct venting
- At 0.82 UEF, it is a non-condensing model rather than a high-efficiency condensing design
- Its high capacity may be unnecessary for smaller households
Best for: Households with multiple simultaneous hot-water needs, natural-gas service, and a suitable indoor direct-vent installation.
Not ideal for: Buyers who need outdoor placement, want to avoid professional installation, or have modest hot-water demand that does not call for high capacity.
- Model:RTG-95DVLN-3
- Fuel:Natural gas
- Installation:Indoor, direct vent
- Type:Non-condensing tankless
- Flow rate:9.5 GPM at 35°F temperature rise
- Heat output:199,900 BTU/hr
- Uniform Energy Factor:0.82
- Temperature range:Up to 140°F
- Warranty:15 years on heat exchanger; 5 years on parts
Our verdict“Choose this Rheem when a high-demand home needs indoor natural-gas tankless capacity and can support direct-vent professional installation.”
CAMPLUX AY132G Portable 5L Propane Tankless Water Heater
The CAMPLUX AY132G is the smaller-flow choice for campers who want a basic portable hot-water point without moving up to a home-scale heater. Its 1.32 GPM output trails the 6L portable heater in this roundup, which lists 1.58 GPM, and its 3.0 PSI minimum pressure also asks more of the water source. In exchange, the stated package includes a shower head, regulator, hose adapter, and mounting hardware, while two D-size batteries support use away from mains power. Six listed protections cover issues such as flame failure and dry combustion. At 14 pounds, it is portable but heavier than the 12-pound 6L alternative. Treat the 176°F maximum as a specification, not a target for showering; this remains an outdoor, single-outlet appliance.
Pros:- Battery-powered operation supports off-grid use
- Includes shower head, regulator, hose adapter, and installation hardware
- Lists protections for flame failure, dry combustion, and low water flow
- Compact design for portable outdoor use
Cons:- 1.32 GPM flow is lower than the 6L portable heater’s 1.58 GPM
- 3.0 PSI minimum pressure may not suit some gravity-fed water sources
- Outdoor use and a propane supply are required
Best for: Campers and RV owners who want a battery-powered portable shower heater with the core hose and propane accessories included.
Not ideal for: Users with very low water pressure or buyers who need higher flow, weather-exposed permanent installation, or whole-house hot water.
- Model:AY132G
- Fuel:Propane
- Flow rate:1.32 GPM
- Capacity:5 L
- Heat output:34,000 BTU
- Minimum water pressure:3.0 PSI
- Power source:Two D-size batteries
- Weight:14 lb
- Warranty:1 year
Our verdict“Pick the AY132G for a compact, accessory-ready camping shower when its 1.32 GPM flow and 3.0 PSI requirement fit your setup.”
ThermoMate CZ422NG Natural Gas Tankless Water Heater Indoor, Up to 5 GPM
At 5 GPM and 113,000 BTU, the ThermoMate CZ422NG sits between the portable heaters and the larger Rheem models. That makes it a more plausible fit for a smaller household than the 9.5 GPM Rheem RTG-95DVLN-3, while its listed 5 GPM output still calls for checking demand against local incoming-water temperatures and simultaneous use. The compact wall-mounted body and smart LED display give owners a readable way to set temperature and view diagnostics. Its listed 98% thermal efficiency is distinct from its 0.81 UEF, so I would not treat those figures as interchangeable or promise a particular bill reduction. The unit needs professional gas and electrical installation, and its 5 GPM ceiling leaves less headroom than the Rheem options for larger families or multiple fixtures.
Pros:- 5 GPM capacity bridges portable units and larger whole-home models
- Smart LED display supports temperature control and diagnostics
- Wall-mounted dimensions suit tighter utility spaces
- Lists freeze and flame-out protection
Cons:- 5 GPM maximum gives less simultaneous-use headroom than either Rheem in this batch
- Professional gas and electrical installation is required
- Listed 98% thermal efficiency and 0.81 UEF are different measures and should not be conflated
Best for: Smaller households with natural-gas service that want an indoor wall-mounted heater and have demand suited to a 5 GPM maximum.
Not ideal for: Large families or homes that frequently run several hot-water fixtures at once; the higher-capacity Rheem models offer more stated flow.
- Model:CZ422NG
- Fuel:Natural gas
- Installation:Indoor, wall mount
- Flow rate:Up to 5 GPM
- Heat output:113,000 BTU
- Thermal efficiency:98%
- Uniform Energy Factor:0.81
- Maximum temperature:140°F
- Certification:CSA, UL
Our verdict“Choose this ThermoMate for a smaller natural-gas household that wants an indoor tankless unit and does not need Rheem-level flow capacity.”
Rheem RTG Series 8.4 GPM Natural Gas Tankless Water Heater (Outdoor, Non-Condensing)
This outdoor Rheem makes the most sense when a home needs substantial natural-gas capacity but indoor vent routing is awkward. It supplies a stated 8.4 GPM at a 35°F rise, below the indoor RTG-95DVLN-3’s 9.5 GPM, yet its outdoor placement avoids that model’s indoor direct-vent requirement. The 180,000 BTU/hr output and Hot Start Programming are aimed at steady whole-home use, with the control panel listed at ±1°F precision. Its non-condensing 0.82 UEF design is simpler than a condensing configuration, but it does not match the higher efficiency associated with condensing models. You also need a suitable outdoor location, and professional installation remains part of the plan. Compared with the 7.0 GPM Rheem RTG-70XLN-3 elsewhere in the roundup, this model offers more stated flow for heavier concurrent demand.
Pros:- 8.4 GPM flow supports heavier household demand than the 7.0 GPM Rheem RTG-70XLN-3
- Outdoor placement avoids indoor vent routing
- Hot Start Programming is designed to reduce cold bursts
- Digital panel lists ±1°F temperature precision
Cons:- Outdoor location is required
- Non-condensing 0.82 UEF design is less efficient than condensing alternatives
- Professional installation is required
Best for: Households with natural-gas service that need high simultaneous-use capacity and have a suitable outdoor installation location.
Not ideal for: Buyers without appropriate outdoor space or those prioritizing indoor placement or a condensing heater’s higher efficiency potential.
- Model:RTG-84XLN-3
- Fuel:Natural gas
- Installation location:Outdoor
- Type:Non-condensing tankless
- Flow rate:8.4 GPM at 35°F temperature rise
- Heat output:180,000 BTU/hr
- Uniform Energy Factor:0.82
- Certification:CSA certified
- Warranty:15 years on heat exchanger; 5 years on parts
Our verdict“Choose this Rheem when you need high whole-home flow and outdoor installation suits the property better than indoor venting.”
APUS Natural Gas Tankless Water Heater, 95,000 BTU, 4.42 GPM Indoor
The APUS pairs a 4.42 GPM flow rate with temperature control rated within ±1°F, making it a fit for households that value steady output across more than one hot water use. Its 95,000 BTU rating is below the Rheem RTG Series 7.0 GPM, so I’d favor the Rheem for heavier simultaneous demand; APUS is the more compact choice when that larger capacity is unnecessary. The listed 98% thermal efficiency and 36 dB operating noise are attractive on paper, while the LED touchscreen simplifies adjustments. The tradeoff is a two-year warranty, plus the need to drain the unit if it will sit unused in freezing conditions. Its 4.42 GPM rating also does not guarantee two showers at full flow in every climate or installation.
Pros:- 4.42 GPM flow rate suits moderate household demand
- Temperature control specified within ±1°F
- Compact wall-mounted body measures 5.91 inches deep
- Listed 98% thermal efficiency and 36 dB noise level
Cons:- Two-year warranty is limited
- Must be drained during long periods of non-use in freezing conditions
- Lower rated flow than the Rheem RTG Series 7.0 GPM
Best for: Households with moderate simultaneous hot water needs that want precise temperature adjustment in a compact indoor unit.
Not ideal for: Homes that regularly run several high-flow fixtures at once or buyers who want longer stated warranty coverage.
- Fuel:Natural gas
- Heat output:95,000 BTU
- Flow rate:4.42 GPM
- Efficiency:98% thermal efficiency; 0.81 UEF
- Maximum temperature:140°F
- Power:120 V; 35 W
- Dimensions:20.55 × 13.27 × 5.91 inches
- Weight:19.2 lb
Our verdict“Choose the APUS for a compact indoor natural gas unit with precise temperature control when 4.42 GPM is enough for your household.”
VEVOR Indoor Gas Tankless Water Heater, 4.3-Gallon, 100,000 BTU
The VEVOR’s LED status display and ±1°F temperature control give buyers a straightforward way to check operation and adjust output. Its listed 16 liters per minute is about 4.2 GPM, placing it in the same general capacity class as the QERPRE 4.3 GPM and Novieex 4.3 GPM models. The data does not establish a meaningful flow advantage over those alternatives, so its clearer differentiator is the display and specified 1/2-inch NPT connection. The 100,000 BTU output and 149°F maximum setting offer flexibility, but indoor installation needs a vent connection, which adds planning and installation work. I’d also treat the description’s “4.3-gallon” capacity cautiously: it lists a flow rate, not a storage tank capacity.
Pros:- LED display shows temperature and operating status
- Temperature control specified within ±1°F
- 100,000 BTU heat output
- 1/2-inch NPT connection is specified
Cons:- Indoor installation requires a vent connection
- Flow rate is listed as 16 liters per minute rather than GPM
- The stated “4.3-gallon” capacity is not clarified as storage capacity
Best for: Buyers fitting an indoor gas tankless unit who want an on-unit temperature and operating-status display.
Not ideal for: Anyone seeking a portable heater or a product listing with a clearly stated flow rate in GPM and detailed venting requirements.
- Heat output:100,000 BTU
- Flow rate:16 L/min (about 4.2 GPM)
- Maximum temperature:149°F
- Temperature control:±1°F
- Power:AC, 120 V
- Maximum pressure:116 psi
- Connection:1/2-inch NPT
- Dimensions:13.78 × 21.65 × 6.3 inches
Our verdict“Pick the VEVOR if an indoor unit with a visible status display and precise temperature control fits your installation plan.”
Indoor Propane Tankless Water Heater, 4.74 GPM
This heater gives propane households an indoor option rated up to 4.74 GPM, with a 95°F–149°F adjustment range and protections for flame failure, freezing, and overheating. Its flow rating edges past the APUS’s 4.42 GPM, but the listed heat output is only 68,000 BTU per hour, so I would not assume it will sustain that maximum flow under every incoming-water temperature or simultaneous-use scenario. The stainless steel body and oxygen-free copper water tank are specified materials; the digital display makes temperature changes easier to manage. Compared with the natural-gas Rheem RTG Series 7.0 GPM, this is a lower-output choice intended for propane installations. It also requires a vent and exhaust setup, and it cannot use natural gas.
Pros:- Rated flow up to 4.74 GPM
- Temperature range spans 95°F to 149°F
- Includes flame failure, freeze, and overheating protection
- Stainless steel body and oxygen-free copper water tank are specified
Cons:- Propane-only fuel limits compatibility
- 68,000 BTU per hour output is below higher-capacity options such as the Rheem RTG Series
- Indoor use requires ventilation and exhaust installation
Best for: Propane users needing an indoor tankless heater for moderate household demand and adjustable output temperature.
Not ideal for: Natural gas homes or households that need a high-output unit to supply several fixtures at once.
- Fuel:Propane (LPG)
- Maximum flow rate:4.74 GPM
- Heat output:68,000 BTU per hour
- Temperature range:95°F–149°F
- Minimum water pressure:3.6 psi
- Water fittings:1/2-inch NPT
- Vent pipe:2.5-inch horizontal
- Materials:Stainless steel body; oxygen-free copper water tank
Our verdict“Choose this model for an indoor propane setup with moderate demand, provided you can accommodate its venting and lower heat output.”
Rheem RTG Series 7.0 GPM Natural Gas Tankless Water Heater Indoor
With 7.0 GPM of rated flow and 160,000 BTU per hour, this Rheem is the strongest fit here for households that want to run multiple showers and other fixtures together. The APUS and VEVOR offer lower flow ratings, making them more suitable for moderate demand; this Rheem gives a larger household more headroom, though actual flow depends on the temperature rise and installation. Its LeakGuard detection, freeze protection, and digital temperature control add useful safeguards to an indoor direct-vent installation. The tradeoff is non-condensing construction, which is less efficient than condensing alternatives, and the venting requirements narrow where it can be installed. Its 0.82 UEF is close to the APUS’s listed 0.81 UEF, so the main reason to choose it is capacity and safety features rather than a clear efficiency lead.
Pros:- 7.0 GPM flow rating supports higher simultaneous demand
- 160,000 BTU per hour output
- LeakGuard, freeze, and flame failure protection
- CSA certified with digital temperature control
Cons:- Non-condensing design is less efficient than condensing models
- Requires indoor direct vent installation
- Higher capacity may be unnecessary for smaller households
Best for: Households with multiple bathrooms that need a natural gas tankless unit for overlapping showers and fixture use.
Not ideal for: Small homes with modest hot water demand or buyers unable to install an indoor direct-vent unit.
- Fuel:Natural gas
- Flow rate:7.0 GPM
- Heat output:160,000 BTU/hr
- Uniform Energy Factor:0.82
- Installation:Indoor, direct vent
- Temperature control:Digital LED, ±1°F precision
- Safety features:LeakGuard, freeze protection, flame failure protection
- Certification:CSA certified
Our verdict“Choose the Rheem when your natural gas household needs more simultaneous hot water capacity than the APUS or VEVOR can provide.”
CAMPLUX AY132 Portable Tankless Water Heater, 1.32 GPM, White
The CAMPLUX is built for a different job from the APUS and Rheem: its 1.32 GPM output is aimed at an outdoor shower or a single low-flow use, not supplying a home’s simultaneous fixtures. At 10 pounds, with two D-size batteries for ignition and included hoses, regulator, and shower head, it is easier to take to a campsite or remote setup than any fixed indoor unit in this group. Its 3.0 PSI startup threshold can help where water pressure is limited. That portability comes with real limits: it uses propane, reaches a listed maximum of 114°F, and is designed for outdoor use. The included accessories simplify a basic setup, but the modest flow and heat output make it a poor substitute for a household gas water heater.
Pros:- Lightweight 10-pound design for portable setups
- 1.32 GPM output provides hot water for an outdoor shower
- Starts at a listed minimum water pressure of 3.0 PSI
- Includes shower head, gas regulator, and hoses
Cons:- Outdoor use only
- Propane and two D-size batteries are required
- 1.32 GPM flow and 114°F maximum temperature limit household use
Best for: Campers, RV users, and off-grid shower setups needing a lightweight outdoor propane heater with included accessories.
Not ideal for: Homeowners looking for a fixed indoor water heater or enough flow for multiple fixtures or high-pressure showers.
- Fuel:Propane
- Power source:Two D-size batteries
- Flow rate:1.32 GPM
- Heat output:34,000 BTU
- Maximum temperature:114°F
- Startup water pressure:3.0 psi minimum
- Weight:10 lb
- Safety features:Anti-freezing, dry combustion, flame failure, high pressure, low flow, and overheat protection
Our verdict“Pick the CAMPLUX for portable outdoor showers and off-grid use, not as a replacement for the higher-capacity APUS or Rheem.”
How We Picked
I ranked these 15 gas water heaters by how well their stated fuel, flow capacity, and installation style match clear buyer needs. For whole-home use, I gave more weight to the higher-capacity Rheem models because they are positioned to serve greater demand than the compact portable heaters. I treated indoor and outdoor designs as different solutions: venting, available space, and exposure to weather can make one workable where the other is not. I also distinguished natural gas models from propane models because they are not interchangeable without the right fuel supply and approved setup.
Within similar capacity bands, the listing information provides limited grounds for declaring a technical winner, so I avoid inventing differences in efficiency, warranty, or construction. Compact units rank for portability and small jobs rather than as substitutes for a whole-home heater. Before buying, readers should verify the exact model’s manual, installation requirements, fuel compatibility, local code requirements, and available service support. Those practical fit checks matter more than a small difference in a headline flow figure.
| gas water heater | Fuel |
|---|---|
| Rheem RTG-70XLN-3 Outdoor Natu | Natural gas |
| Propane Tankless Water Heater | Propane |
| Tankless Propane Gas Water Hea | Propane gas |
| QERPRE Tankless Water Heater N | Natural gas |
| Novieex Natural Gas Tankless W | Natural gas |
| Outdoor Propane Tankless Water | Propane |
| Rheem RTG-95DVLN-3 Indoor Natu | Natural gas |
| CAMPLUX AY132G Portable 5L Pro | Propane |
| ThermoMate CZ422NG Natural Gas | Natural gas |
| Rheem RTG Series 8.4 GPM Natur | Natural gas |
| APUS Natural Gas Tankless Wate | Natural gas |
| VEVOR Indoor Gas Tankless Wate | — |
| Indoor Propane Tankless Water | Propane (LPG) |
| Rheem RTG Series 7.0 GPM Natur | Natural gas |
| CAMPLUX AY132 Portable Tankles | Propane |
Factors to Consider When Choosing Gas Water Heater
Start by checking whether a heater can work safely and legally at your site, then compare capacity against your actual hot-water use. The following choices can prevent common mismatches that a product name or BTU figure alone will not reveal.
Match Flow Capacity to Simultaneous Use
GPM describes how much water a heater can deliver under specified conditions, but the usable output also changes with incoming water temperature and the temperature rise the unit must provide. List the fixtures likely to run together, such as a shower and kitchen tap, and use their combined demand as a starting point. A high advertised flow figure does not guarantee that a unit will maintain that flow during a cold winter inlet temperature. Check the manufacturer’s performance chart for the temperature rise expected in your region. Avoid sizing only for the busiest imagined moment if that would force an unnecessarily large installation. For a cabin or single sink, a compact model may be a better fit than a whole-home unit.
Confirm Fuel Before Comparing Models
Natural gas and propane require different fuel supplies and appliance configurations, so identify what is available at the installation location first. A propane heater cannot be assumed to work on a natural gas line, or vice versa, unless the manufacturer explicitly approves a conversion kit and qualified conversion. Check the required gas pressure, pipe sizing, and supply capacity against the model manual. Long or undersized gas lines can limit performance even when the heater’s published BTU rating looks ample. If a property uses bottled propane, account for tank capacity and cold-weather supply needs. This check can rule out unsuitable options before you compare features.
Plan the Installation Location and Venting
Indoor models need an approved venting route and enough clearance for service, while outdoor models need a suitable exterior location and protection consistent with their instructions. Do not assume an outdoor unit can be placed anywhere because it is weather-rated; freezing conditions, wind, and local code still matter. Indoor combustion equipment also needs the prescribed air supply and clearances around windows or other openings. Measure the proposed space and map the vent route before purchase, since retrofitting can add complexity. Ask a qualified installer to confirm the location, gas line, vent materials, and condensate handling where applicable. A modest capacity advantage may not justify a difficult or noncompliant installation.
Choose Household Equipment or Portable Use
Portable propane heaters serve a different job from permanently installed whole-home equipment. They can suit outdoor washing, camping, or a temporary utility setup, but the low-flow models in this lineup are not direct replacements for a household system serving several fixtures. Check whether the unit requires a particular water pressure, flow activation threshold, battery supply, or connection arrangement. Follow all rules for outdoor placement and keep combustion equipment away from enclosed spaces. A handle and compact body help with transport, but they do not remove the need for stable water and propane connections. Decide where and how often you will use the heater before treating portability as a benefit.
Look Beyond BTU and GPM
BTU input indicates the rate of fuel energy consumption, not a complete measure of delivered hot-water performance or operating cost. Compare efficiency documentation, temperature-rise charts, control options, warranty terms, and parts availability for the exact model. Ask whether freeze protection is included and what conditions it covers, especially for outdoor installation. For indoor units, review the vent system and any requirements for condensate drainage. A less familiar brand may appear similar on capacity, yet service access and replacement parts can affect ownership over time. Use the manufacturer’s documentation and installer guidance to resolve gaps in a product listing.
Size for Realistic Demand and Future Needs
Oversizing can increase installation demands, while undersizing can leave multiple users competing for hot water. Consider whether household size, bathroom count, or planned renovations are likely to change during the heater’s service life. A larger unit only helps if the gas supply, water flow, venting, and electrical requirements support it. For a small household with staggered use, a mid-capacity unit may be more sensible than selecting the highest number in the lineup. If demand is uncertain, have an installer calculate it using local inlet temperatures and fixture flow rates. That step helps translate a product specification into a realistic result at your taps.
Frequently Asked Questions
Can I replace my current heater with any gas model that has a similar GPM rating?
No. A similar flow rating does not confirm that a replacement matches your fuel, gas line capacity, venting, clearances, or local installation rules. Compare the old unit’s setup with the new model’s installation manual before ordering. Indoor and outdoor units usually require different locations and vent arrangements. Have a qualified installer confirm compatibility, especially if the new heater has a higher BTU input.
How do I choose between an indoor and an outdoor tankless gas water heater?
Base the choice on the available installation location, climate, venting path, and local code. An indoor unit needs an approved route for exhaust and the clearances its manual specifies. An outdoor model can avoid indoor vent routing, but it must be installed where its weather and freeze-protection instructions can be met. Compare the actual installation scope with a qualified installer before treating either format as simpler.
Is a portable propane heater suitable as my home’s main water heater?
The compact portable models in this roundup have much lower stated flow than the larger whole-home units, so they are generally better suited to limited outdoor tasks. Whether any particular unit can serve a permanent application depends on its listing, installation instructions, and applicable codes. Check the hot-water demand of all fixtures you expect to use, not just the heater’s maximum flow headline. Confirm that the model is approved for the intended setting before connecting it to household plumbing.
Does a higher BTU rating mean the heater will provide more usable hot water?
BTU input alone cannot tell you how much hot water will reach your fixtures at the temperature you need. Delivered flow depends on factors such as incoming water temperature, temperature rise, heater design, and the gas supply. Compare the manufacturer’s flow chart at a temperature rise that reflects your location. Also verify that the gas line can meet the model’s input requirement, since inadequate supply can undermine performance.
What should I verify before buying a natural gas or propane tankless heater?
Confirm the fuel type and supply pressure, then check the unit’s installation location, venting, electrical needs, and clearance requirements. Read the exact model manual rather than relying only on a shortened product listing. Ask an installer to assess the gas line and site conditions, including cold-weather exposure for an outdoor unit. Check warranty coverage, service availability, and replacement-part access as well. These checks help identify costly fit problems before purchase.
Conclusion
For the strongest whole-home capacity in this lineup, I recommend the Rheem RTG-95DVLN-3 as best overall, provided its indoor installation requirements fit your home. Buyers who want an outdoor natural gas unit should compare the Rheem RTG-70XLN-3 and the 8.4 GPM Rheem outdoor model against their demand and site conditions; the higher-flow RTG-95DVLN-3 is the premium choice for greater simultaneous use where indoor venting is workable. For beginners, I would start with a model whose fuel, location, manual, and installer support are easy to confirm, rather than choosing by BTU alone; the listed specs do not establish a clear beginner-focused winner. The CAMPLUX AY132G and similar portable propane heaters make more sense for outdoor or occasional tasks, while the QERPRE and Novieex offer similar stated capacity for buyers comparing indoor natural gas options. Choose only after verifying the exact model’s fit with a qualified installer and your local requirements.
