As Amazon Associates, we earn from qualifying purchases. This means we may receive a small commission at no extra cost to you if you click through and make a purchase.
As an Amazon Associate we earn from qualifying purchases. Links on this page are affiliate links.
Finding the best tankless water heaters under $300 requires careful attention to electrical and gas requirements. The Thermomate 18kW Electric Tankless Water Heater leads this list because its 18 kW wattage delivers a robust 4.4 GPM flow for indoor showers with strong circuits. We compared 15 models using only the specifications published on their listings. This approach helps you match a unit’s power, size, and fuel type to your home’s infrastructure. Use this guide to decide which heater fits your space and usage needs.
01 Match wattage to your electrical panel
Electric models like the Thermomate and Orbek require 240V power and 18 kW circuits. Gas units such as the VancEpic and APUS use propane or natural gas instead. Choose based on your existing infrastructure. Electric units offer precise digital control. Gas models provide high flow rates for whole-house use. Verify your panel capacity before buying.
| # | Product | Best for | Price |
|---|---|---|---|
| 1 | Thermomate 18kW Electric Tankless Water Heater Best overall | Indoor showers with strong electrical circuits | |
| 2 | Westinghouse 14kW Electric 240V Best 14 kw | compact point-of-use installations with smart control needs | |
| 3 | VancEpic 4.8 GPM Natural Gas Tankless Heater Best budget | whole-house natural gas hot water | |
| 4 | Ranein 3.6 GPM Indoor Propane Tankless Heater Also great | Propane whole-home heating | |
| 5 | Orbek 18kW 240V Tankless Electric Water Heater Also great | Whole-house electric heating with high flow | |
| 6 | WINTEMP 18 kW Tankless Water Heater with WiFi Also great | WiFi control and mild climate homes | |
| 7 | APUS 95,000 BTU 4.42 GPM Indoor Propane Heater Best premium | indoor multi-fixture propane use | |
| 8 | SIVUATEK 18kW Electric Tankless Water Heater Also great | Whole-house electric hot water with high efficiency | |
| 9 | WINTEMP 18kW Electric Tankless Water Heater Also great | 2-3 point household use with 240V power | |
| 10 | ThermoMate Propane 3.06 GPM Also great | Single shower propane setups | |
| 11 | APUS 18kW 4.4 GPM Tankless Water Heater Also great | Whole-house hot water with high flow rates | |
| 12 | Ranein 18kW 4.3 GPM Electric Water Heater Also great | whole-house hot water with precise temperature control | |
| 13 | Rheem 13kW Compact Electric Tankless Water Heater Also great | tight spaces and low flow needs | |
| 14 | NOVIEEX 18 kW 4.9 GPM Tankless Water Heater Also great | multi-fixture small homes | |
| 15 | GASLAND 4 GPM Indoor Natural Gas Tankless Water Heater Also great | Compact indoor natural gas hot water needs |
02 The best fit for you
- You need the best overall electric performance – Thermomate 18kW Electric Tankless Water Heater – The 18kW power and 4.4 GPM flow suit indoor showers with strong circuits.
- You want the most compact model on the list – Westinghouse 14kW Electric 240V – Its 8-inch width and smart features fit point-of-use installations perfectly.
- You need whole-house natural gas hot water – VancEpic 4.8 GPM Natural Gas Tankless Heater – The 4.8 GPM flow and 110,000 BTU output handle whole-house demand.
- You want WiFi control for your heater – WINTEMP 18 kW Tankless Water Heater with WiFi – The WINTEMP 18kW model includes WiFi connectivity for remote management.
- You need propane heating for multiple fixtures – APUS 95,000 BTU 4.42 GPM Indoor Propane Heater – The 4.42 GPM flow and 95,000 BTU output support simultaneous use.
Thermomate 18kW Electric Tankless Water Heater
Best for: Indoor showers with strong electrical circuits
- Fuel Type
- Electric
- Max Flow Rate
- Up to 4.4GMP
- Heating Capacity
- 18kW
- Installation Location
- Indoor
- Voltage
- 240 Volt
- Temperature Range
- 80°F to 140°F
The Thermomate ET180 is an indoor electric tankless water heater with 18kW heating capacity. It delivers up to 4.4 GPM at 240V. The unit features a digital display adjusting from 80°F to 140°F. Its compact design saves space. It suits households needing reliable on-demand hot water. The system includes safety protections and self-modulating technology for efficiency.
- 18kW heating capacity for strong performance
- Up to 4.4 GPM max flow rate
- Digital display with 1°F adjustment increments
- ETL certified for safety standards
- Self-modulating technology for energy efficiency
- Requires a substantial 80Amp breaker setup
- Higher power draw than lower kW models
- Indoor installation only limits placement options
- You have the electrical capacity for 80Amp breakers
- You need a compact indoor unit for showers
- You want precise temperature control in 1°F increments
- You only have a standard 40Amp circuit available
- You require outdoor installation capability
- You prefer gas fuel sources over electric
Verdict: Thermomate 18kW Electric Tankless Heater offers robust 18kW heating and 4.4 GPM flow for homes with adequate electrical infrastructure. It fits users seeking precise digital temperature control and compact indoor mounting.
Westinghouse 14kW Electric 240V
Best for: compact point-of-use installations with smart control needs
- Fuel Type
- Electric
- Max Flow Rate
- 3.38 GPM
- Heating Capacity
- 14 kW
- Voltage
- 240 V
- Fixture Capacity
- 2 Point of Use
- Temperature Range
- 86-140°F
This Westinghouse unit delivers 14 kW of heating power at 240 volts. It provides a maximum flow rate of 3.38 GPM, suitable for two points of use. The device measures 11 inches in height and 8 inches in width. You get smart WiFi control and ETL certification for safety. It fits well in compact spaces where you need reliable hot water for sinks or showers.
- 14 kW heating capacity for instant hot water
- 3.38 GPM max flow rate supports two fixtures
- Smart WiFi voice control with Alexa and Google Home
- ETL certified with 4-layer safety protection
- Compact 11" H x 8" W design saves space
- 14 kW power is lower than the 18 kW standard on this list
- 3.38 GPM flow rate is lower than the 4.22+ GPM options available
- Limited to two points of use, unlike whole-house models
- You need a compact unit for a single sink or small bathroom
- You want smart WiFi control for remote temperature adjustment
- You have a 240V circuit with a 60-amp breaker ready
- You need to supply hot water to an entire house simultaneously
- You require a flow rate higher than 3.38 GPM
- You prefer a higher power output like 18 kW for faster heating
Verdict: Westinghouse 14kW Electric Tankless Water Heater suits you if you prioritize smart features and compact size over maximum flow. It is a solid choice for point-of-use applications where 14 kW is sufficient.
VancEpic 4.8 GPM Natural Gas Tankless Heater
Best for: whole-house natural gas hot water
- Fuel Type
- Natural Gas
- Max Flow Rate
- 4.8 GPM
- Heating Capacity
- 110,000 BTU
- Installation Location
- Indoor
- Fixture Capacity
- 3-5 water outlets
- Features
- Tankless, Child Safety Lock, LED Display
The VancEpic VH11K-W-NG-U01 is an indoor natural gas tankless water heater with a 4.8 GPM flow rate and 110,000 BTU heating capacity. It supports 3 to 5 water outlets simultaneously. The unit features an oxygen-free copper heat exchanger and ±1°F temperature control. Its compact dimensions are 14.4 by 24.6 inches. This model suits families needing high-volume hot water for whole-house use.
- 110,000 BTU heating capacity
- 4.8 GPM max flow rate
- ±1°F precise temperature control
- Oxygen-free copper heat exchanger
- Child safety lock feature
- Indoor-only installation requirement
- Heavier 25.4-pound build
- 2-year warranty length
- You need high flow for multiple outlets
- You have access to natural gas
- You want precise temperature stability
- You require outdoor installation
- You prefer propane fuel type
- You need a longer warranty period
Verdict: VancEpic 110,000 BTU Natural Gas Heater delivers strong performance for large households. It fits buyers who prioritize flow rate and temperature precision over outdoor versatility.
Ranein 3.6 GPM Indoor Propane Tankless Heater
Best for: Propane whole-home heating
- Fuel Type
- Propane
- Max Flow Rate
- 3.6 GPM
- Heating Capacity
- 80,000 BTU
- Installation Location
- Indoor
- Fixture Capacity
- 2-3 water points
- Temperature Range
- 95°F-149°F
The Ranein propane tankless water heater delivers 80,000 BTU of heating power at a max flow rate of 3.6 GPM. It supports 2-3 water points simultaneously, making it suitable for whole-home use. The unit features an oxygen-free copper heat exchanger and dual heating chambers for stable temperature control. It includes preset modes for specific needs and operates indoors with included venting.
- 80,000 BTU heating capacity
- 3.6 GPM max flow rate
- Dual heating chambers
- Oxygen-free copper heat exchanger
- Includes vent pipe
- Lower flow rate than 4.42 GPM competitor
- Lower BTU than 95,000 BTU competitor
- Indoor-only installation
- You need propane heating for a home
- You want stable temperature with dual chambers
- You prefer included venting hardware
- You require electric power only
- You need outdoor installation
- You want higher flow rates
Verdict: Ranein Propane 3.6 GPM Indoor Heater suits households needing reliable propane heating with stable temperature control. It fits users who value dual heating chambers and included venting over higher flow rates.
Orbek 18kW 240V Tankless Electric Water Heater
Best for: Whole-house electric heating with high flow
- Fuel Type
- Electric
- Max Flow Rate
- 4.22 GPM
- Heating Capacity
- 18 kW
- Voltage
- 240 V
- Fixture Capacity
- 2-3 Point of Use
- Installation Type
- Whole House
This Orbek unit delivers 18 kW of heating power at 240 V. It provides a maximum flow rate of 4.22 GPM for whole-house use. The compact design mounts to walls and requires 75 A of amperage via two 40 A breakers. ETL certification ensures safety standards are met. You get instant hot water without a storage tank. This model suits homes needing reliable, on-demand heating for multiple fixtures.
- 18 kW heating capacity for strong hot water output
- 4.22 GPM maximum flow rate supports whole-house use
- ETL certified for electrical safety compliance
- Compact wall-mounted design saves floor space
- Requires 75 A amperage, higher than many competitors
- Fixture capacity rated for 2-3 points of use only
- You need a high-capacity electric heater for whole-house use
- You have the electrical capacity for 75 A amperage
- You prefer ETL-certified units for safety assurance
- You only have 40 A total electrical capacity available
- You need a unit rated for more than 3 simultaneous fixtures
- You are installing in a location with limited wall space
Verdict: Orbek M-18 18kW Electric Tankless is a robust option for households with adequate electrical infrastructure. It fits buyers who prioritize high flow rates and safety certifications over compact amperage requirements.
WINTEMP 18 kW Tankless Water Heater with WiFi
Best for: WiFi control and mild climate homes
- Fuel Type
- Electric
- Max Flow Rate
- 4.3 GPM
- Heating Capacity
- 18kW
- Voltage
- 240V
- Installation Type
- Whole House
- Features
- Tankless
The WINTEMP WN18 is an 18kW electric unit rated for 240V with a maximum flow of 4.3 GPM. It uses self-modulating technology to adjust power based on flow and inlet temperature. The compact 11.1 by 19.1 inch design mounts on walls. It includes remote WiFi control for temperature adjustments. This model suits homes in mild climates needing steady hot water for showers.
- 18kW heating capacity delivers up to 4.3 GPM
- WiFi remote control for temperature adjustments
- Self-modulating energy savings technology
- ETL certified for safety
- Compact wall-mounted design saves space
- Requires 75A total amperage with two 40A breakers
- Limited to 2-year manufacturer warranty
- Maximum flow rate is lower than some 18kW competitors
- You need remote temperature control via WiFi
- You have a 150A household electrical service
- You want ETL certified safety standards
- You cannot install two 40A double-pole breakers
- You use 8/2 AWG wiring for connections
- You live in a cold climate requiring higher flow
Verdict: WINTEMP 18kW Electric Tankless Water Heater fits users with strong electrical infrastructure who value remote control convenience. It provides reliable hot water for mild climate households.
APUS 95,000 BTU 4.42 GPM Indoor Propane Heater
Best for: indoor multi-fixture propane use
- Fuel Type
- Propane
- Max Flow Rate
- 4.42 GPM
- Heating Capacity
- 95,000 BTU
- Installation Location
- Indoor
- Voltage
- 120V
- Fixture Capacity
- 2–3 Fixtures
The APUS Propane Tankless Water Heater delivers 95,000 BTU and a 4.42 GPM flow rate for indoor use. It supports 2–3 fixtures with a 98% thermal efficiency rating. The unit features an LED touchscreen and operates at 36dB. It maintains temperature within ±1°F. This model suits households needing steady hot water for multiple simultaneous uses without the bulk of a tank.
- 95,000 BTU heating capacity
- 4.42 GPM maximum flow rate
- 98% thermal efficiency
- LED touchscreen interface
- 36dB quiet operation
- Indoor-only installation limit
- Propane fuel type requirement
- 2-year warranty coverage
- You need hot water for 2–3 fixtures simultaneously
- You have a propane supply available
- You prefer indoor installation with digital controls
- You require outdoor installation capability
- You use natural gas instead of propane
- You need a warranty longer than 2 years
Verdict: APUS Propane 95k BTU 4.42 GPM offers high efficiency and precise temperature control for indoor homes. It fits users who need reliable simultaneous hot water for multiple fixtures.
SIVUATEK 18kW Electric Tankless Water Heater
Best for: Whole-house electric hot water with high efficiency
- Fuel Type
- Electric
- Heating Capacity
- 18kW
- Voltage
- 240V
- Fixture Capacity
- 3–4 simultaneous usage points
- Temperature Range
- 86°F to 131°F
- Installation Type
- Whole House
This SIVUATEk unit delivers 18kW of heating power at 240V, supporting 3–4 simultaneous usage points. It features 99.8% thermal efficiency and an LED display allowing precise temperature control from 86°F to 131°F. The compact design fits under-sink or on-wall installations. You get instant hot water with no standby loss. It suits whole-house needs where high flow and energy savings matter most.
- 18kW heating capacity for strong hot water output
- 99.8% thermal efficiency reduces energy waste
- LED display with 1°F increment temperature adjustments
- Compact dimensions for flexible installation
- Requires 2 x 40-amp circuit breakers for operation
- Flow rate capped at 3–4 simultaneous usage points
- Temperature range maxes out at 131°F
- You need high heating power for whole-house use
- You want precise temperature control via LED display
- You have the electrical capacity for 40-amp breakers
- You only have 20-amp circuits available
- You need more than 4 simultaneous usage points
- You prefer gas or propane fuel sources
Verdict: SIVUATEK 18kW Electric Tankless Water Heater fits homes needing high power and precise temperature control. It works well for whole-house setups with adequate electrical infrastructure.
WINTEMP 18kW Electric Tankless Water Heater
Best for: 2-3 point household use with 240V power
- Fuel Type
- Electric
- Max Flow Rate
- 4.3 GPM
- Heating Capacity
- 18kW
- Voltage
- 240V
- Fixture Capacity
- 2-3 points of use
- Features
- Tankless, LED Display
This WINTEMP unit delivers up to 4.3 GPM of hot water using 18kW of power at 240V. It features an LED display and self-regulating technology that adjusts energy use based on flow. The compact design mounts to the wall, saving space. It supports 2-3 points of use, making it suitable for whole-house applications. ETL certification ensures safety standards are met for residential installation.
- 18kW heating capacity provides up to 4.3 GPM flow rate
- LED display shows real-time water temperature
- Self-regulating technology saves energy by adjusting power to flow
- ETL certified for safety with leakage and overheat protection
- Wall-mounted design occupies minimal space
- Requires 2 x 40 Amp DP breakers and 2 x 8/2 AWG wiring
- Heavier at 12 pounds compared to lighter plastic units
- Limited to 2-3 points of use rather than full whole-house capacity
- You need a high-flow electric heater for multiple fixtures
- You have the required 240V electrical infrastructure installed
- You want an ETL-certified unit with an LED display
- You only have a single 40 Amp breaker available
- You need a unit lighter than 12 pounds for easy mounting
- You require a gas-powered heater for higher efficiency
Verdict: WINTEMP 18kW Electric Tankless Water Heater fits homes needing reliable hot water for 2-3 fixtures. It suits users with the necessary 240V electrical setup who value safety certifications and real-time temperature monitoring.
ThermoMate Propane 3.06 GPM
Best for: Single shower propane setups
- Fuel Type
- Propane
- Max Flow Rate
- Up to 3.06 GPM
- Heating Capacity
- 75,000 BTU
- Installation Location
- Indoor
- Voltage
- 120V
- Temperature Range
- 90–140°F
This ThermoMate unit delivers up to 3.06 GPM using 75,000 BTU of propane power. It features a 98% thermal efficiency rating and a 90–140°F temperature range. The compact design fits indoor spaces with standard 3/4-inch water connections. You get precise flow control and eight safety protections. This model suits single-shower setups or small household applications where propane fuel is available.
- Up to 3.06 GPM max flow rate
- 75,000 BTU heating capacity
- 98% thermal efficiency with 0.81 UEF
- Eight integrated safety protections
- Precise temperature control within ±1°F
- Lower max flow rate of 3.06 GPM compared to 4.22–4.42 GPM on other list items
- Lower heating capacity of 75,000 BTU versus 80,000–110,000 BTU on gas competitors
- Indoor installation only, excluding outdoor use
- You need a compact unit for a single bathroom shower
- You have access to propane fuel and indoor venting
- You prioritize high thermal efficiency and safety features
- You require a flow rate above 3.5 GPM for whole-house use
- You need natural gas compatibility instead of propane
- You want an outdoor-rated unit for exterior mounting
Verdict: ThermoMate 3.06 GPM Propane Heater offers efficient, safe heating for single-shower needs. You should choose this if you value high efficiency and compact indoor placement over high-volume flow.
APUS 18kW 4.4 GPM Tankless Water Heater
Best for: Whole-house hot water with high flow rates
- Fuel Type
- Electric
- Max Flow Rate
- Up to 4.4 GPM
- Heating Capacity
- 18kW
- Installation Location
- Indoor
- Voltage
- 240V
- Fixture Capacity
- 2–3 Points
The APUS 18kW tankless water heater delivers up to 4.4 GPM at 240V for whole-house use. Its 99.8% thermal efficiency and self-modulating technology adjust power to flow rates, reducing standby loss. The unit measures 13.7 by 11.4 by 3.54 inches and weighs 15.2 pounds. You get precise digital control from 86 to 131°F with memory retention. This model suits those needing reliable instant hot water for two to three simultaneous fixtures.
- High 99.8% thermal efficiency with self-modulating power adjustment
- Generous 4.4 GPM max flow rate for multiple fixtures
- Precise digital temperature control in 1°F increments
- Slim 3.54-inch depth saves wall space
- Built-in memory restores settings after power outages
- Heavier at 15.2 pounds compared to lighter competitors
- Requires two 40A breakers and 8 AWG wire
- Indoor installation only
- You need a high-flow unit for whole-house hot water
- You want precise temperature control with digital display
- You have the electrical capacity for dual 40A breakers
- You only have a single 40A circuit available
- You need an outdoor-rated unit
- You prefer a lighter, more compact installation
Verdict: APUS 18kW Electric Tankless Water Heater fits households needing high flow and precise temperature control. It works well for whole-house setups where electrical infrastructure supports dual 40A breakers.
Ranein 18kW 4.3 GPM Electric Water Heater
Best for: whole-house hot water with precise temperature control
- Fuel Type
- Electric
- Max Flow Rate
- 4.3 GPM
- Heating Capacity
- 18 kW
- Voltage
- 240 V
- Fixture Capacity
- 2–3 household water outlets
- Temperature Range
- 86°F to 131°F
The Ranein 18kW unit delivers up to 4.3 GPM at 240V, supporting 2–3 outlets simultaneously. Its 99% thermal efficiency reduces standby loss, while the 86°F to 131°F range allows precise control. This compact, CSA-certified heater fits whole-house needs where electrical capacity allows for two 40A circuits.
- High 99% thermal efficiency for energy savings
- Precise temperature control in 1°F increments
- CSA certified for safety standards
- Supports 2–3 household outlets at 4.3 GPM
- Requires two dedicated 40A double-pole breakers
- Heavier at 17.4 pounds than some compact models
- You need whole-house hot water for 2–3 outlets
- You have the electrical capacity for two 40A circuits
- You want precise temperature adjustments in 1°F increments
- You cannot install two dedicated 40A double-pole breakers
- You prefer a lighter unit under 15 pounds
- You only need a single point-of-use heater
Verdict: Ranein 18kW Electric Tankless Water Heater suits homes with strong electrical panels that need reliable whole-house flow. It delivers consistent heat for multiple fixtures without the bulk of a storage tank.
Rheem 13kW Compact Electric Tankless Water Heater
Best for: tight spaces and low flow needs
- Max Flow Rate
- up to 3.17 GPM
- Heating Capacity
- 13kW
- Voltage
- 240V
- Features
- Tankless
- Dimensions
- 12.6 × 8.25 × 3.63 inches
- Weight
- 3.97 pounds
The Rheem RTEX-13 is a compact 13kW electric tankless water heater designed for residential use. It delivers up to 3.17 GPM at 240V with 99.8% energy efficiency. This unit features external digital controls for precise temperature adjustment and includes a water-saver shower head. Its small footprint makes it suitable for tight spaces, offering reliable instant hot water for single fixtures or small households.
- 13kW heating capacity for instant hot water
- Compact dimensions: 8.25 x 3.63 x 12.6 inches
- 99.8% energy efficiency rating
- External digital thermostat with 1-degree accuracy
- Lower 13kW power output compared to 18kW competitors
- Lower 3.17 GPM flow rate than many 4+ GPM models
- Heavier 3.97 pounds build than some lighter units
- You need a compact unit for tight spaces
- You want precise digital temperature control
- You prioritize energy efficiency in a single sink setup
- You require high flow rates for whole-house use
- You need higher than 3.17 GPM capacity
- You prefer lighter units under 3 pounds
Verdict: Rheem RTEX-13 Compact Tankless Heater fits buyers needing a space-saving, efficient solution for low-to-medium flow demands. It suits single-kitchen or bathroom applications where precision control matters more than high volume.
NOVIEEX 18 kW 4.9 GPM Tankless Water Heater
Best for: multi-fixture small homes
- Fuel Type
- Electric
- Max Flow Rate
- 4.9 GPM
- Heating Capacity
- 18kW
- Installation Location
- Indoor
- Voltage
- 240V
- Fixture Capacity
- 2-3 Points
The NOVIEEX 18kW electric tankless water heater delivers up to 4.9 GPM at 240V. It suits small-to-medium homes with 2-3 simultaneous fixtures. The unit features an LED display and adjusts temperature in 1°F steps. Its 99.8% thermal efficiency reduces standby waste. You get indoor installation with a slim profile that saves space.
- High flow rate of 4.9 GPM for multiple fixtures
- Precise temperature control in 1°F increments
- 99.8% thermal efficiency eliminates standby loss
- Slim wall-mount design saves space
- Requires 2 x 40A double-pole circuit breakers
- Needs 2 sets of 8 AWG wires with ground
- Indoor installation only
- You need hot water for 2-3 simultaneous fixtures
- You have the required 240V electrical capacity
- You want precise temperature adjustments
- You only have a single 1-point fixture
- You need outdoor installation
- You cannot support 75A max current
Verdict: NOVIEEX 18kW Electric Tankless Heater fits homes needing high flow for multiple bathrooms. It suits users with strong electrical setups who want precise temperature control.
GASLAND 4 GPM Indoor Natural Gas Tankless Water Heater
Best for: Compact indoor natural gas hot water needs
- Fuel Type
- Natural Gas
- Max Flow Rate
- 4 GPM
- Heating Capacity
- Up to 98,500 BTU
- Installation Location
- Indoor
- Fixture Capacity
- Two showers and a kitchen faucet
- Features
- Tankless
The GASLAND CG360NGN1 delivers up to 98,500 BTU of heating power with a maximum flow rate of 4 GPM. This natural gas unit supports two showers and a kitchen faucet simultaneously. It features precision temperature control within ±0.5°F and operates quietly indoors. Its compact dimensions of 15.1 inches wide and 9.4 inches high save space in tight areas like cabinets or utility closets.
- High heating capacity of up to 98,500 BTU
- Max flow rate of 4 GPM for multi-point use
- Precision temperature control within ±0.5°F
- Compact form factor at 15.1 inches wide
- Lower max flow rate of 4 GPM compared to higher-capacity models on the list
- Lower heating capacity of 98,500 BTU compared to 110,000 BTU units
- Indoor installation only, excluding outdoor use
- You need a compact unit for tight indoor spaces
- You require steady temperature control within ±0.5°F
- You want to supply hot water to two showers and a faucet
- You need a flow rate higher than 4 GPM
- You require outdoor installation capabilities
- You prefer propane fuel over natural gas
Verdict: GASLAND 4 GPM Natural Gas Heater suits small households needing reliable indoor hot water with precise temperature stability. It fits well in compact spaces where higher flow rates are unnecessary.
03 Specifications side by side
| Spec | Thermomate 18kW Electric Tankless Water Heater | Westinghouse 14kW Electric 240V | VancEpic 4.8 GPM Natural Gas Tankless Heater | Ranein 3.6 GPM Indoor Propane Tankless Heater | Orbek 18kW 240V Tankless Electric Water Heater | WINTEMP 18 kW Tankless Water Heater with WiFi | APUS 95,000 BTU 4.42 GPM Indoor Propane Heater | SIVUATEK 18kW Electric Tankless Water Heater | WINTEMP 18kW Electric Tankless Water Heater | ThermoMate Propane 3.06 GPM | APUS 18kW 4.4 GPM Tankless Water Heater | Ranein 18kW 4.3 GPM Electric Water Heater | Rheem 13kW Compact Electric Tankless Water Heater | NOVIEEX 18 kW 4.9 GPM Tankless Water Heater | GASLAND 4 GPM Indoor Natural Gas Tankless Water Heater |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Fuel Type | Electric | Electric | Natural Gas | Propane | Electric | Electric | Propane | Electric | Electric | Propane | Electric | Electric | – | Electric | Natural Gas |
| Max Flow Rate | Up to 4.4GMP | 3.38 GPM | 4.8 GPM | 3.6 GPM | 4.22 GPM | 4.3 GPM | 4.42 GPM | – | 4.3 GPM | Up to 3.06 GPM | Up to 4.4 GPM | 4.3 GPM | up to 3.17 GPM | 4.9 GPM | 4 GPM |
| Heating Capacity | 18kW | 14 kW | 110,000 BTU | 80,000 BTU | 18 kW | 18kW | 95,000 BTU | 18kW | 18kW | 75,000 BTU | 18kW | 18 kW | 13kW | 18kW | Up to 98,500 BTU |
| Installation Location | Indoor | – | Indoor | Indoor | – | – | Indoor | – | – | Indoor | Indoor | – | – | Indoor | Indoor |
| Voltage | 240 Volt | 240 V | – | – | 240 V | 240V | 120V | 240V | 240V | 120V | 240V | 240 V | 240V | 240V | – |
| Fixture Capacity | – | 2 Point of Use | 3-5 water outlets | 2-3 water points | 2-3 Point of Use | – | 2–3 Fixtures | 3–4 simultaneous usage points | 2-3 points of use | – | 2–3 Points | 2–3 household water outlets | – | 2-3 Points | Two showers and a kitchen faucet |
| Temperature Range | 80°F to 140°F | 86-140°F | – | 95°F-149°F | – | – | 95–140°F | 86°F to 131°F | – | 90–140°F | 86–131°F | 86°F to 131°F | – | 77°F to 140°F | – |
| Installation Type | – | – | – | – | Whole House | Whole House | – | Whole House | – | – | – | Whole House | – | – | – |
| Features | Tankless | Tankless | Tankless, Child Safety Lock, LED Display | Tankless | Tankless | Tankless | Tankless | Tankless | Tankless, LED Display | Tankless | Tankless, LED Display | Tankless | Tankless | Tankless | Tankless |
| Application | Shower | Point of Use | – | – | Point of Use | – | – | – | – | Bathroom | – | – | – | Bathroom | – |
| Form Factor | – | Compact | – | Compact | Compact | – | – | – | – | – | – | – | – | – | Compact |
| Wattage | 18 kW | 14 kW | – | – | 18 kW | 18 kW | – | 18 kW | 18 kW | – | 18 kW | 18 kW | – | 18 kW | – |
| Intended Use | – | Home | – | Home | Home | – | – | – | – | – | – | – | – | – | – |
| Dimensions | 13.1 × 13.1 × 17.1 inches | 8 × 8 × 11 inches | 14.4 × 14.4 × 24.6 inches | 13.8 × 13.8 × 21.7 inches | 8 × 8 × 11 inches | 19.1 × 11.1 × 4 inches | 5.9 × 5.9 × 20.6 inches | 12.2 × 12.2 × 17.3 inches | 9.7 × 9.7 × 14 inches | 28.1 × 15.9 × 9.84 inches | 11.4 × 11.4 × 13.7 inches | 13.8 × 13.8 × 18.7 inches | 12.6 × 8.25 × 3.63 inches | 11.1 × 11.1 × 15.9 inches | 15.1 × 15.1 × 9.4 inches |
| Weight | – | – | 25.4 pounds | 18 pounds | – | 12 pounds | 19.2 pounds | – | 12 pounds | – | 15.2 pounds | 17.4 pounds | 3.97 pounds | – | – |
| Size | 240V/18kW | S-14 | 4.8GPM, 110,000BTU, NG | 3.6 GPM Indoor | M-18 | 18kW | – | – | WN-18 | – | – | – | Compact | – | 4 GPM NG |
| Color | Gray | – | Non-Condensing | Gray-LPG | Snow | Gray | Propane Gas,4.42GPM,95,000BTU，Space Gray | Gray | Gray | Metallic Silver | Gray | Gray | Gray | Silver | Black |
| Model | ET180 | HEU-ET014KA1G-A2 | VH11K-W-NG-U01 | RH8K-LPG-FC-RATING | HEU-ET018A5W-M0 | WN18 | AP-AWH-Q13LPG | TSB-180 | YQ-WN18K | CZ264LP | AP-ADSK180-H18 | RE18K | RTEX-13 | DS-18 | CG360NGN1 |
You can evaluate flow rate specs across the best tankless water heaters under 300 to verify circuit capacity.
04 How to choose the right tankless heater
Check your electrical capacity
Electric tankless heaters demand significant power. Most units in this guide, including the Thermomate and Orbek, require 240V power and 18 kW circuits. You must verify your home has the necessary electrical infrastructure to support these loads. If your panel lacks capacity, these high-wattage models will not function. Lower wattage options like the Rheem 13kW suit homes with limited electrical power. Always consult a licensed electrician to confirm your panel can handle the amperage before purchasing an electric unit for your home.
Match fuel type to home
Your available fuel source dictates which heater you can install. Electric models like the Westinghouse 14kW need only a 240V outlet. Gas units require a gas line and proper venting. The VancEpic 4.8 GPM Natural Gas Heater suits homes with natural gas access. The Ranein Propane Heater works for those with propane tanks. Choose the fuel type that matches your existing infrastructure. This decision impacts installation complexity and long-term operating costs. Do not attempt to convert fuel types without professional guidance.
Assess flow rate needs
Flow rate determines how many fixtures can run simultaneously. The VancEpic offers 4.8 GPM, suitable for whole-house use in small homes. The Thermomate provides 4.4 GPM for indoor showers. Lower flow units like the Thermomate Propane 3.06 GPM fit single-shower setups. Consider your household size and peak usage times. If multiple bathrooms run at once, you need higher GPM. Point-of-use models serve single sinks. Match the GPM spec to your actual demand to avoid cold water surprises during use.
Verify installation location
Tankless heaters vary in size and installation requirements. The Westinghouse 14kW is compact, measuring 8 inches wide, ideal for tight spaces. The VancEpic is larger at 24.6 inches tall. Most units listed are for indoor use. The APUS Propane heater is also designed for indoor installation. Ensure you have adequate space and proper ventilation, especially for gas models. Outdoor units require weather-resistant construction. Check the dimensions in the specs to ensure the unit fits your planned mounting location in your home.
Consider smart features
Some heaters offer digital displays or WiFi connectivity for better control. The WINTEMP 18kW model includes WiFi for remote monitoring. The VancEpic features an LED display for temperature viewing. The Thermomate provides precise digital temperature control. These features help you monitor water temperature and adjust settings easily. Decide if remote control is necessary for your lifestyle. Basic models may lack these conveniences but still deliver hot water. Choose based on your preference for technology integration versus simple operation in your home.
05 Frequently asked questions
Can a tankless water heater power multiple showers at once?
It depends on the flow rate and your home’s infrastructure. The VancEpic 4.8 GPM Natural Gas model supports whole-house use, making it suitable for multiple fixtures. Electric options like the Thermomate 18kW offer 4.4 GPM, which works well for indoor showers if you have strong circuits. Lower flow models, such as the ThermoMate Propane 3.06 GPM, are better for single-shower setups.
Do I need a gas line or just electricity for a tankless heater?
You need whichever fuel source your home already has. Electric models, including the Thermomate and Orbek 18kW units, require 240V power and adequate electrical panels. Gas models like the VancEpic and APUS Propane heaters use natural gas or propane. Choosing the right type depends entirely on your existing infrastructure rather than preference alone.
How much space does a tankless water heater take up?
These units are compact and wall-mounted. The Westinghouse 14kW is exceptionally small at 8 inches wide, ideal for tight point-of-use spots. The WINTEMP 18kW with WiFi is also slim at 11.1 inches wide. Larger gas models like the VancEpic are taller at 24.6 inches but still save floor space compared to traditional tank heaters.
What is the difference between electric and gas tankless heaters?
Electric models like the Rheem 13kW and SIVUATEK 18kW use 240V power and offer precise digital control. Gas models, such as the GASLAND 4 GPM and Ranein Propane, use natural gas or propane for higher flow rates. Electric units are often more compact, while gas units generally provide higher capacity for whole-house needs.
Are these heaters safe for indoor installation?
Most models in this list are designed for indoor use. The VancEpic 4.8 GPM and Ranein Propane heaters include safety features like child locks and LED displays. Electric units like the Thermomate and Orbek are also built for indoor mounting. Always verify that your electrical or gas connections meet local codes for safe indoor operation.
Which tankless heater is best for a small bathroom?
The Westinghouse 14kW Electric model is ideal for small spaces. It is compact at 8 inches wide and designed for point-of-use applications. The Rheem 13kW is also a strong choice for low-to-medium flow needs in tight spaces. These units provide efficient heating without taking up much room in a small bathroom.
Do I need professional installation for these units?
Professional installation is recommended for all models due to electrical or gas requirements. Electric units like the Thermomate 18kW require 240V circuits and proper wiring. Gas models like the APUS 95,000 BTU need correct venting and gas line connections. Improper installation can void safety certifications and cause operational issues.
