A tankless water heater can supply a washer without keeping a storage tank hot around the clock. The right choice depends less on the washer itself than on your incoming water temperature, fuel supply, and whether other fixtures need hot water at the same time.
These 10 options span compact electric units and higher-output gas models. Use the guide below to narrow the field before checking installation requirements and performance ratings for your home.
Best 10 Tankless Water Heaters for Laundry Picks for 2026
Best for Busy Households
Westinghouse 7.9 GPM Natural Gas Heater
- Up to 7.9 GPM; 180,000 BTU
- Built-in Wi-Fi controls
- Starts at 0.53 GPM flow
Best For: Laundry alongside multiple household fixtures
Best Compact Gas Pick
APUS 4.42 GPM Natural Gas Heater
- 4.42 GPM; 95,000 BTU
- Slim wall-mounted design
- 95–140°F adjustable setting
Best For: Moderate hot-water demand in a smaller utility space
Best Propane Option
- Propane; up to 4.3 GPM
- 95–149°F adjustable range
- Professional installation required
Best For: Propane-equipped homes with moderate hot-water demand
Best Vent-Free Electric Pick
- Up to 5.9 GPM rated flow
- No gas venting required
- Substantial 240V wiring requirements
Best For: Homes equipped for a 24kW electric heater
Natural Gas for Busy Homes
MIZUDO 199,000 BTU Indoor Heater
- Natural gas; up to 10.3 GPM advertised
- Temperature settings up to 149°F
- Wi-Fi controls; dedicated vent required
Best For: Natural-gas homes running laundry alongside other fixtures
Electric Laundry Option
- 18kW, 240V electric model
- Advertised flow up to 4.4 GPM
- Self-modulating, serviceable elements
Best For: Homes with suitable 240V power and modest simultaneous demand
Propane for Multi-Fixture Demand
MIZUDO 199,000 BTU Indoor Heater
- Propane; up to 10.3 GPM advertised
- Temperature settings up to 149°F
- Wi-Fi controls; dedicated vent required
Best For: Propane homes running laundry alongside other fixtures
Best Electric Option
WINTEMP WN18 18kW WiFi Tankless Heater
- 18kW electric; up to 4.3 GPM
- Self-modulating with WiFi control
- Needs two 40-amp breakers
Best For: Homes with sufficient electrical capacity seeking electric hot water for laundry and household use
Best Indoor Gas Option
ThermoMate CZ422NG 5 GPM Natural Gas Heater
- Up to 5 GPM; 113,000 BTU
- Indoor, wall-mounted design
- Needs gas, venting, and 120V
Best For: Natural-gas homes supplying laundry alongside other fixtures
Best Portable Propane Option
18L 4.76 GPM Outdoor Water Heater
- Portable propane-powered design
- Stated flow up to 4.76 GPM
- 113°F maximum listed temperature
Best For: Outdoor utility washing and portable setups, rather than standard indoor laundry
Best for Busy Households – Westinghouse 7.9 GPM Natural Gas Heater
Among tankless water heaters for laundry, this Westinghouse model is the high-capacity natural gas option: its rated output reaches 7.9 GPM and 180,000 BTU for households running several fixtures.
Best For: Homes that need hot water for laundry alongside showers or dishwashing.
Pros:
- Rated for up to 7.9 GPM, with capacity for three simultaneous showers.
- Built-in Wi-Fi supports remote temperature adjustments, status checks, and fault alerts.
- Activates at flows as low as 0.53 GPM and operates at water pressure as low as 15 PSI.
Cons:
- Requires natural gas, 120V power, and an indoor installation.
- Its rated maximum flow may not reflect output under every incoming-water temperature.
The 3/4-inch NPT plumbing requirement is worth checking before purchase. If your priority is keeping laundry from monopolizing the household hot-water supply, this is the strongest capacity match in this group.
Best Compact Gas Pick – APUS 4.42 GPM Natural Gas Heater
For shoppers comparing tankless water heaters for laundry in a smaller utility space, the APUS offers a 4.42 GPM rated flow and 95,000 BTU natural gas output in a slim wall-mounted design.
Best For: Homes seeking a compact indoor gas unit for laundry and moderate simultaneous fixture use.
Pros:
- Rated to serve two showers and a sink at once.
- Adjustable 95–140°F temperature setting with a stated ±1°F control range.
- Measures approximately 20.55 inches high, 13.27 inches wide, and 5.91 inches deep.
Cons:
- Its 4.42 GPM rating leaves less capacity headroom than the larger Westinghouse unit.
- Requires a natural gas connection and 120V power.
The included vent pipe and touchscreen are useful details, but confirm the venting and gas setup for your home before buying. The 0.66 GPM activation threshold also matters if other low-flow fixtures share the system.
Best Propane Option – Novieex 4.3 GPM Indoor Heater
If your home uses propane, this 100,000 BTU indoor model is an alternative among tankless water heaters for laundry. Its rated output is up to 4.3 GPM, with an adjustable 95–149°F temperature range.
Best For: Propane-equipped homes that need laundry hot water without a storage tank.
Pros:
- Rated for up to 4.3 GPM and 100,000 BTU.
- Digital thermostat offers a stated ±1°F temperature control range.
- Wall-mounted design includes an LED touchscreen and flue pipe.
Cons:
- Calls for licensed professional installation and 110–120V AC power.
- Manufacturer recommends use below 2,000 feet altitude.
The seller describes simultaneous shower and sink use, but a washing machine can add a substantial draw; check your expected fixture combination and incoming-water temperature when sizing. This model uses 1/2-inch NPT gas and water connections.
Best Vent-Free Electric Pick – Rheem RTEX-24 24kW Heater
For homes avoiding a gas hookup or exhaust vent, the Rheem RTEX-24 is an electric option among tankless water heaters for laundry. This 24kW, 240V unit is rated for up to 5.9 GPM, provided it is properly sized for the application.
Best For: Homes with sufficient electrical capacity that want electric hot water for laundry and other fixtures.
Pros:
- Up to 5.9 GPM rated flow for multiple-fixture applications.
- No gas venting required.
- Digital temperature adjustment in 1-degree increments from 80–140°F.
Cons:
- Requires three 40-amp double-pole breakers and three sets of #8 AWG copper conductors with ground.
- Rheem recommends a minimum 200-amp household electrical service panel.
Check the electrical requirements before weighing its compact size and vent-free installation. As with other tankless models, actual hot-water flow depends on the temperature rise your household needs.
Natural Gas for Busy Homes – MIZUDO 199,000 BTU Indoor Heater
For households comparing tankless water heaters for laundry, this natural-gas MIZUDO model is designed to serve the washer alongside other hot-water fixtures. Its 199,000 BTU input and advertised flow rate of up to 10.3 GPM make it a whole-home option, though actual flow depends on the required temperature rise.
Best For: Homes with natural gas that need hot water for laundry and multiple fixtures at the same time.
Pros:
- Advertised capacity of up to 10.3 GPM, with temperature settings up to 149°F.
- Modulating heat control and a 0.53 GPM activation threshold.
- Wi-Fi app controls and Alexa compatibility.
Cons:
- Indoor installation requires the specified 3-inch by 5-inch concentric vent system and a 120V outlet.
- Manufacturer does not recommend use above 3,000 feet.
This is the higher-demand natural-gas choice of the three. Check the installation requirements and your household’s expected temperature rise before relying on the maximum flow rating.
Electric Laundry Option – Rheem RTEX-18 18kW Heater
Among tankless water heaters for laundry, the Rheem RTEX-18 is an electric alternative for buyers who prefer not to install a gas appliance. Its 18kW rating and advertised flow of up to 4.4 GPM warrant a closer look at the washer’s hot-water demand and the home’s incoming water temperature.
Best For: Homes with a suitable 240V electrical supply and more modest simultaneous hot-water needs.
Pros:
- Self-modulation adjusts power to hot-water demand.
- Digital temperature display with thermostatic control rated to ±1°F accuracy.
- Two copper immersion heating elements are field-serviceable.
Cons:
- Requires a 240V supply for its 18kW load.
- Advertised flow tops out at 4.4 GPM, less than the two gas models here.
The RTEX-18 offers straightforward electric operation and serviceable elements, but verify electrical capacity and expected flow at your desired temperature rise before pairing it with a washer and other fixtures.
Propane for Multi-Fixture Demand – MIZUDO 199,000 BTU Indoor Heater
For propane-equipped homes shopping for tankless water heaters for laundry, this indoor MIZUDO unit is designed to supply a washer while other fixtures run. It lists 199,000 BTU of heating input and up to 10.3 GPM of flow; achievable flow will vary with the temperature rise needed.
Best For: Propane homes that need laundry hot water alongside showers, sinks, or dishwashing.
Pros:
- Advertised flow of up to 10.3 GPM and settings up to 149°F.
- 0.53 GPM activation threshold and modulating temperature control.
- App-based monitoring and temperature adjustment, plus Alexa compatibility.
Cons:
- Requires the specified 3-inch by 5-inch concentric vent system and 120V power.
- Not recommended by the manufacturer above 3,000 feet.
This is the propane counterpart to the high-output natural-gas model. Its fuel and venting needs are the key differences to check when planning a laundry-room installation.
Best Electric Option – WINTEMP WN18 18kW WiFi Tankless Heater
Among tankless water heaters for laundry, the WINTEMP WN18 is an electric option worth considering when you want on-demand hot water without a storage tank. Its self-modulating controls adjust power to water flow and incoming temperature, while WiFi control lets you change the setting remotely.
Best For: Homes with adequate electrical capacity that want an electric heater serving laundry and other household hot-water needs.
Pros:
- Rated at 18kW with a stated maximum output of 4.3 GPM.
- Self-modulating operation adjusts power as demand changes.
- Compact wall-mounted design includes WiFi control and an LED display.
Cons:
- Requires two 40-amp double-pole breakers and two 8/2 AWG wiring runs; 150-amp household service is recommended.
- Actual hot-water flow depends on incoming water temperature and demand.
The electrical requirements are the deciding factor. Have a qualified electrician check your panel and wiring before choosing this unit for a laundry setup.
Best Indoor Gas Option – ThermoMate CZ422NG 5 GPM Natural Gas Heater
For shoppers comparing tankless water heaters for laundry in a home with natural gas, the indoor ThermoMate CZ422NG offers a stated maximum of 5 GPM and 113,000 BTU of heating output. Its controls adjust heating as flow changes, making it a potential fit when laundry shares hot-water demand with bathrooms or the kitchen.
Best For: Homes with a natural-gas supply seeking one indoor tankless unit for laundry and multiple household fixtures.
Pros:
- Rated for up to 5 GPM with 113,000 BTU of heating output.
- Wall-mounted design saves floor space compared with a storage tank.
- LED display shows settings and diagnostic information.
Cons:
- Requires a natural-gas connection, exhaust venting, and 120V power.
- The stated two-shower performance assumes 65°F inlet water; colder supply water can reduce usable flow.
This is the stronger multi-fixture candidate of the indoor models here by stated maximum flow, but the installation connections and your incoming water temperature matter as much as the headline GPM.
Best Portable Propane Option – 18L 4.76 GPM Outdoor Water Heater
This portable propane model is a different kind of choice among tankless water heaters for laundry: it is geared toward camping, RV use, outdoor bathing, and pet washing rather than a conventional household laundry hookup. Its stated 4.76 GPM output may appeal if you need hot water at an outdoor utility washing station.
Best For: Portable outdoor washing setups where propane-powered hot water is more useful than a permanent indoor installation.
Pros:
- Portable design suited to outdoor and RV use.
- Stated maximum flow of 4.76 GPM and heating output of 115,425 BTU/hour.
- Includes protections for overheating, flame failure, and low-flow ignition.
Cons:
- Product notes emphasize outdoor uses, not a standard indoor laundry installation.
- Maximum listed water temperature is 113°F.
Consider this one for portable utility washing, not as a direct substitute for a permanently installed indoor water heater. Confirm your intended setup and temperature needs before buying.
How We Picked These Tankless Water Heaters for Laundry
We compared the listed gas and electric models by fuel type, rated output, stated flow rate where available, and the installation demands those specifications imply. The selection includes units suited to a dedicated laundry connection as well as higher-capacity options worth considering for multiple fixtures. Published GPM figures are not guaranteed at every home: actual hot-water flow depends on how much the heater must raise the incoming water temperature.
Quick Comparison: Which Type Fits Your Setup?
Electric models: The 18 kW and 24 kW options avoid gas piping and combustion venting, but require substantial 240 V electrical capacity. They are most compelling when your panel can support the required circuits and your hot-water demand is modest.
Mid-output gas models: The approximately 95,000–115,000 BTU options may suit a washer and limited additional demand, provided their rated flow holds up at your required temperature rise.
High-output gas models: The 180,000–199,000 BTU options offer more headroom for simultaneous use, but need appropriately sized fuel supply, approved venting, and a suitable indoor installation location. Match natural gas or propane to the fuel you actually have; the two are not interchangeable without an approved conversion.
Key Buying Factors for Tankless Water Heaters for Laundry
Temperature Rise Matters More Than Advertised GPM
Find your cold-water inlet temperature, then subtract it from your target hot-water temperature. A colder inlet means a larger rise and less flow from the same heater. Check manufacturer performance charts at that rise rather than comparing headline GPM numbers alone.
Match Output to Your Washer and Other Fixtures
Consult your washer’s manual for its water-heating behavior and connection requirements. Many modern machines use little hot water or heat water internally; others draw from a hot-water line. If a shower or sink may run during a load, include that combined demand when sizing the heater.
Check Installation Before Price
For electric units, verify breaker, wire, and panel requirements with a qualified electrician. For indoor gas units, confirm gas-line capacity, venting, combustion-air requirements, condensate provisions if applicable, and local code with a licensed installer. Also check minimum activation flow, water-quality guidance, maintenance access, and whether the unit can be located near the laundry area.
Who Should Buy Which Tankless Water Heaters for Laundry?
Choose an 18 kW electric model if you want a relatively focused laundry application and its temperature-rise chart meets your needs. Consider 24 kW electric when your electrical service allows it and you need more output. A mid-output gas model can be a practical fit for a home with the correct fuel and moderate demand. Look to 180,000–199,000 BTU gas models when laundry overlaps with other hot-water use. In every case, confirm the exact unit’s specifications against your climate, fixtures, and installation before buying.
