A propane tankless water heater heats water as you need it, saving the floor space used by a storage tank. The right choice depends on how many fixtures you use at once, how cold your incoming water gets, and whether you need an indoor or outdoor unit. These five LP models range from compact, lower-output options to higher-capacity heaters designed for several fixtures.
| Water heater | Installation | Listed capacity | Notable feature |
|---|---|---|---|
| QERPRE Propane Tankless Water Heater | Vent pipe included; placement not specified | 3.6 GPM, 85,000 BTU | Kitchen and bathtub modes |
| Westinghouse Outdoor Propane Tankless Water Heater | Outdoor | 5.1 GPM, 120,000 BTU | Wired digital controller |
| ThermoMate CZ422LP | Indoor, vented | Up to 5 GPM, 102,000 BTU | LED display and diagnostic codes |
| CAMPLUX Outdoor Propane Tankless Water Heater | Outdoor, no vent required | Up to 6.4 GPM; 5.28 GPM stated for simultaneous use | Designed for multiple water points |
| Konfino Indoor Propane Tankless Water Heater | Indoor, vented | 4.3 GPM, 102,000 BTU | Touchscreen and temperature memory |
Table of Contents
Our Picks: Best Lp On Demand Water Heater reviews
QERPRE: Compact Choice with Convenient Preset Modes
The QERPRE is a lower-capacity propane tankless heater rated at 3.6 GPM and 85,000 BTU. Its listing says it can supply two or three points, but your actual results will depend on incoming water temperature and how many fixtures are drawing hot water at once. It includes a vent pipe and uses standard 1/2-inch NPT fittings, according to the product details.
Its standout feature is a set of three operating modes. The Kitchen Mode is preset to 100°F, while Bathtub Mode can alert you when a selected volume is reached. The listing also describes a four-season mode and temperature control designed to hold the set temperature within ±1°F. These controls may be useful if you want presets for common household tasks rather than adjusting the temperature each time.
The compact 22-by-14-by-6.5-inch body may suit a space-conscious installation. The trade-off is its more modest output compared with the Westinghouse, ThermoMate, CAMPLUX, and Konfino models. The listing also advises against use above 2,000 feet. The supplied listing information marks this item unavailable, so check the Amazon page before treating it as a purchase option.
Pros:
- Compact design with vent pipe included
- Kitchen and bathtub presets add task-specific controls
- Listed temperature stability of ±1°F
- Low-water-pressure start range listed from 3.6 to 110 PSI
Cons:
- Lower rated output than the other listed models
- Listing information marks it unavailable; verify before planning an installation
Verdict: Consider the QERPRE if its presets and compact size fit your needs, but verify availability and confirm that 3.6 GPM is enough for your household.
Westinghouse: Outdoor Model for Several Household Fixtures
This Westinghouse model is designed for outdoor wall mounting and is rated at 5.1 GPM and 120,000 BTU. The manufacturer describes it as suitable for two to four fixtures at once, with examples including showers, sinks, a dishwasher, and laundry. Its listed 0.53 GPM activation flow and 15 PSI minimum pressure may also make it worth considering for plumbing systems with lower water pressure.
A wired digital controller lets you set the temperature within a listed range of 95°F to 158°F. The product description says its self-modulating controls adjust gas input with water flow to help keep the outlet temperature steady. It also lists CSA/ANSI certification and safety features such as flame-failure and low-flow protection.
Because this is an outdoor unit, it can be a fit if you want to avoid installing an indoor vent pipe. However, the listing notes that freeze protection applies to the heater itself, not exposed external pipes. It also says the unit needs continuous power for its freeze-protection feature; if temperatures fall below freezing without power, drain the heater fully. This model offers more stated capacity than the QERPRE, though less than the CAMPLUX’s advertised maximum.
Pros:
- Outdoor wall-mount design with no indoor vent route to plan
- 5.1 GPM rating and support for multiple fixtures as described by the manufacturer
- Wired controller with a broad temperature adjustment range
- Low listed activation flow and minimum pressure
Cons:
- External pipes need separate freeze protection
- Freeze protection depends on power and does not remove the need to drain the unit in some conditions
Verdict: The Westinghouse is a strong option to compare for outdoor installation and moderate multi-fixture demand, especially if its controller and low-flow activation suit your plumbing.
ThermoMate CZ422LP: Indoor Heater with a Diagnostic Display
The ThermoMate CZ422LP is an indoor propane heater rated up to 5 GPM and 102,000 BTU. The product description says it can supply two showers at once under stated conditions, including 65°F incoming water and a 105°F outlet temperature. That context matters: a colder inlet or more simultaneous use can affect how much hot water the unit can deliver.
Its 3.5-inch LED display shows temperature, flow, fan, and flame status, while diagnostic codes are intended to help with troubleshooting. The heater has a listed 90°F to 140°F adjustment range, a 120V power connection, and standard 3/4-inch water connections. Its listed dimensions—21 inches high, 13 inches wide, and 7 inches deep—may help when comparing available wall space.
The listing identifies CSA certification and eight protections, including freeze, flame-out, and overheating protection. It also lists a 3-inch vent connection, so indoor installation needs a compatible vent route and careful attention to the product instructions. At up to 5 GPM, it has more stated capacity than the QERPRE and Konfino, but it does not match the CAMPLUX’s advertised maximum.
Pros:
- Up to 5 GPM rating for household hot-water demand
- Display provides operating information and diagnostic codes
- Compact wall-mount dimensions
- Listing specifies CSA certification and multiple protection features
Cons:
- Indoor installation requires a compatible vent setup
- Output depends on inlet temperature and simultaneous use
Verdict: Choose the ThermoMate if you need an indoor unit with a clear diagnostic display and can accommodate its venting and electrical requirements.
CAMPLUX: Higher-Output Outdoor Option for Busy Homes
The CAMPLUX is an outdoor propane unit rated at 150,000 BTU, with an advertised maximum of 6.4 GPM. Its product details also give a more specific simultaneous-use figure of 5.28 GPM and describe delivering 105°F water at 2 GPM per listed point, based on 65°F inlet water. The listing says it can serve several water points, but the higher maximum should not be treated as a guarantee that every fixture can run at once.
This model is designed for outdoor installation and does not require a vent, according to its listing. It has standard 3/4-inch NPT water and gas fittings and measures about 23.43 by 14.92 by 6.69 inches. The manufacturer describes temperature control with ±1°F fluctuations and lists CSA certification along with anti-freeze, overheat, dry-fire, and flame-failure protections.
Its rated capacity makes it the highest-output option in this group on paper. That can be useful for homes with several hot-water needs, but actual performance still depends on incoming water temperature and fixture flow. The listing advises draining the unit when temperatures fall below 5°F or during extended periods without use, and recommends use below 2,000 feet in elevation.
Pros:
- Highest advertised maximum flow rate among these five models
- Outdoor installation does not require a vent, per the listing
- Listed 150,000 BTU input and multi-point use
- CSA certification and several listed safety protections
Cons:
- Actual flow can be lower than the advertised maximum, especially with multiple fixtures
- Cold-weather use requires attention to draining and freeze protection
Verdict: The CAMPLUX is the capacity-focused pick for an outdoor installation, provided its real-world flow and winterization needs match your home and climate.
Konfino: Indoor Model with Touchscreen and Temperature Memory
The Konfino is an indoor propane tankless heater rated at 4.3 GPM and 102,000 BTU. The manufacturer describes it as suitable for up to four fixtures when properly sized, and gives two showers plus a sink as an example for a small or medium home. Actual capacity varies with incoming water temperature and simultaneous use, so those figures are best treated as sizing guidance rather than a promise for every setup.
A touchscreen displays temperature, operating status, and fault codes. The unit also has temperature memory, a 95°F to 140°F adjustment range, and a 120V connection for its controls and fan. Its listed dimensions are about 20.55 inches high, 13.27 inches wide, and 5.91 inches deep, making it a compact wall-mount option to compare with the ThermoMate.
The product description lists a vent pipe for compatible indoor installations, an oxygen-free copper heat exchanger, and a freeze safeguard. It also stresses that the safeguard does not eliminate freezing risk: draining the heater and water lines is advised in cold conditions or during long periods without use. This is a practical option if you want indoor installation and straightforward controls, but confirm the included vent works with your planned setup.
Pros:
- 4.3 GPM rating for moderate household demand
- Touchscreen, fault codes, and temperature memory
- Compact wall-mount design with vent pipe listed as included
- Product description includes freeze-safeguard and draining guidance
Cons:
- Indoor installation requires compatible venting
- Freeze safeguards do not replace draining and other winter precautions
Verdict: The Konfino is worth considering for an indoor installation if its 4.3 GPM rating fits your demand and you value touchscreen controls and temperature memory.
How to Choose an LP On-Demand Water Heater
Match flow rate to your household demand
Start by listing the fixtures that may run at the same time, such as a shower, kitchen sink, or washing machine. Then compare their combined flow needs with the heater’s rating. A model’s maximum GPM does not necessarily mean it can supply that amount at every temperature rise or through several fixtures at once. Check the manufacturer’s sizing details for your incoming water temperature and expected use.
Account for incoming water temperature
A heater has to raise incoming water to your chosen output temperature. Colder incoming water requires a larger temperature increase, which can reduce the flow available at the desired temperature. Look for performance figures that state the inlet and outlet temperatures used, and compare those conditions with your home rather than relying on a headline GPM alone.
Choose indoor or outdoor installation
Indoor models in this group use vent pipes to route combustion gases outside. Outdoor models avoid an indoor vent route, but they need an appropriate outdoor mounting location and protection for exposed water pipes. Confirm the installation type, vent requirements, clearances, and local rules before buying. A qualified installer can help verify that the location and connections are suitable.
Check LP supply and connections
Compare the heater’s gas connection and requirements with your propane supply before installation. The listings specify different connection details, so do not assume every unit uses the same fittings. Have a qualified professional confirm that the supply and installation meet the product instructions and applicable local requirements.
Plan for freezing weather and power needs
Some models list built-in freeze protection, but the details make clear that this may not protect external pipes or cover every cold-weather situation. Check whether a model needs continuous electricity for its freeze feature, and follow its draining instructions when power may be lost or the unit will sit unused. Winterization needs can be an important difference between models, particularly for outdoor installations.
Compare controls and temperature range
Choose controls that suit how you use hot water. A wired controller, touchscreen, display, presets, or temperature memory can make operation more convenient, but each feature differs by model. Compare the listed temperature range with the settings you want, and consider whether you prefer a simple control or an on-screen view of operating status and fault codes.
Check certification, altitude, and installation details
Read the complete product specifications and installation manual before purchase. Confirm the listed certification, vent or outdoor-mounting requirements, electrical connection, fitting sizes, and any altitude limits. The QERPRE and CAMPLUX listings, for example, advise against use above 2,000 feet. If your home is at a higher elevation, check directly with the manufacturer or a qualified installer before choosing a unit.
Frequently Asked Questions
What does GPM mean on a tankless water heater?
GPM means gallons per minute, a measure of water flow. For a tankless heater, the useful flow depends on how much the water needs to be heated and how many fixtures are running. Compare performance conditions as well as the headline GPM rating.
Can one LP tankless heater run two showers at once?
Some of these models are described as supporting two showers or several fixtures, but that depends on flow, inlet-water temperature, and the outlet temperature you want. Check the manufacturer’s sizing information and consider your home’s simultaneous demand before choosing.
Is an outdoor propane water heater better than an indoor model?
Neither type is automatically better. An outdoor model avoids an indoor vent route, while an indoor model may suit a protected utility space if you can install compatible venting. Compare location, climate, pipe protection, and installation requirements.
Do tankless heaters provide hot water instantly?
They heat water when a fixture calls for it, rather than storing a tank of hot water. Water still has to travel through the plumbing to the fixture, so the wait can depend on the distance between the heater and the tap.
Do these models need electricity?
Several listings specify a 120V connection or describe powered controls, fans, or freeze-protection features. Requirements vary by model, so check the installation instructions and make sure the planned location has the needed power.
Will built-in freeze protection protect the whole plumbing system?
No. The Westinghouse listing says its freeze protection applies to the heater, not external pipes, and the other product descriptions also recommend draining in certain cold or extended non-use conditions. Follow the exact winterization instructions for the model you choose.
Which model is the best fit for a small home?
The best fit depends on your fixtures and installation location. The QERPRE has the lowest listed flow rate, while the Konfino and ThermoMate offer higher indoor ratings. For outdoor installation and greater stated capacity, compare the Westinghouse and CAMPLUX. Size the unit for your actual demand rather than choosing by flow rate alone.
Conclusion
For higher stated capacity in an outdoor model, the CAMPLUX is the leading option in this group, while the Westinghouse offers a lower activation-flow figure and a wired controller. For indoor installations, compare the ThermoMate’s diagnostic display with the Konfino’s touchscreen and temperature memory. The QERPRE’s presets are appealing for more modest demand, but its supplied listing information marks it unavailable. Before buying any model, verify its availability, installation requirements, and capacity for your home’s incoming water temperature and simultaneous fixture use.
