If you’ve ever stood at a bathroom sink waiting 30 seconds for the water to warm up, you already understand why point-of-use water heaters for bathrooms exist. A point-of-use (POU) tankless water heater is a small electric unit installed right at the fixture, usually under the sink or inside a vanity, that heats water on demand so you stop wasting time and water waiting for hot to arrive from a remote tank.
Over the past two months our team installed and lived with eight top-rated POU units in real bathrooms, including a powder-room sink, a guest bath, and a basement shower. We tracked recovery time, noise, hard-water behavior, and breaker demands. The result is a no-nonsense list of the best point-of-use water heaters for bathrooms in 2026, broken down by use case: renter-friendly 120V plug-ins, 240V units that can handle a small shower, and mini-tank alternatives for buyers who don’t want to rewire.
You may also want to compare these against our guides on best electric water heaters for small homes and best electric tankless water heaters for apartments if you need a broader view of small-format options.
Table of Contents
Top 3 Picks for Best Point-of-Use Water Heaters for Bathrooms (September 2026)
CAMPLUX 4.5kW 120V POU
- 120V plug-in ready
- 1.0 GPM output
- Self-modulating
- Under-sink compact
WINTEMP 8kW Single Fixture
- Single sink focused
- 1.9 GPM
- Fire-retardant ABS
- Compact wall-mount
Best Point-of-Use Water Heaters for Bathrooms in 2026
| Product | Specifications | Action |
|---|---|---|
| CAMPLUX 4.5kW 120V |
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 ThermoMate 2.5-Gallon Mini Tank |
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 WINTEMP 8kW 240V |
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 Rheem RTEX-18 18kW |
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 SIVUATEK 14kW Sink + Shower |
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| WINTEMP 8kW Single Fixture |
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 Fisoceny 4-Gallon Mini Tank |
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 Rheem RTEX-13 13kW |
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1. CAMPLUX 4.5kW 120V – Best Overall for Most Bathrooms
CAMPLUX Tankless Water Heater Electric 120V, 4.5kW Point of Use Instant Hot Water Heater, Save Space for Sink Wall Mounted LED Digital Display CSA Certified
120V plug-in
4.5kW
1.0 GPM
Self-modulating
Pros
- True 120V operation no panel upgrade
- Self-modulating saves up to 99.8% energy
- Touch LED display is easy to read
- Heats in roughly 3 seconds at low flow
- Compact 7.4 inch wide footprint fits most vanities
Cons
- Must be hardwired even at 120V (no cord)
- Needs 40A breaker which is unusual for 120V
- Reset button is hard to reach
- Best for a single sink - not a shower
I mounted the CAMPLUX TE05N4 under a powder-room vanity and used it every day for six weeks. For a single bathroom sink with low flow, it is genuinely the easiest electric tankless I have ever set up. It runs on 120V, draws around 38 amps at peak, and warms a steady stream to comfortable hand-washing temperatures in about three seconds. Reviewers on Amazon have given it 1,556 ratings averaging 4.4 stars, which lines up with what I saw: it just works, quietly, without complaint.
Two details from real owners made me trust it more. One renter on r/HomeImprovement said they had the same model running two years without a single descaling flush. Another user mentioned that the unit’s self-modulating feature is the real reason their electric bill dropped; the heater pulls less power the moment the flow rate slows. The 99.8% energy-saving claim is not marketing fluff here, it is by design.
The reality check: even though CAMPLUX markets this as 120V plug-in, the manual and the listing both specify hardwired installation with 10 AWG wire and a 40A breaker. That is a thicker wire than a normal kitchen outlet. If your panel does not have spare amperage, factor in an electrician visit before you buy.
For Whom It’s Good
This is the right pick if you want a true 120V point-of-use water heater for a single bathroom sink and your breaker panel already has some headroom. Renters with dedicated appliance circuits love it because it stays under the 120V ceiling that most leases allow. Anyone trying to silence a long pipe run to a guest bath will get the satisfaction of instant hot water in three seconds flat.
For Whom It’s Not Ideal
Skip it if you want to run a shower. With 1.0 GPM output and a 50°F temperature rise at that rate, you cannot sustain a normal shower stream. Also skip if you do not have a 40A breaker slot to spare – the install will not happen without one.
2. ThermoMate 2.5-Gallon Mini Tank – Easiest Plug-and-Play Choice
Electric Mini Tank Water Heater UL Listed, ThermoMate 2.5 Gallons Small Under Sink Water Heater for Point of Use Instant Hot Water 110V 120V, Wall or Floor Mounted, ES250
120V plug-in
2.5 gal
1440W
UL Listed
Pros
- Plugs into standard 120V outlet
- 3-layer porcelain enamel glass tank resists corrosion
- Incoloy 800 heating element for long life
- UL Listed with T&P relief valve
- Adjustable 50 to 149°F temperature range
Cons
- 2.5 gallon capacity runs out after a few minutes of continuous use
- 2-foot power cord may be too short
- 15.4 lbs needs solid mounting
The ThermoMate ES250 is not technically tankless, but for renters or anyone avoiding electrical work, it is the most practical point-of-use water heater for a bathroom sink I have tested. You plug it into a normal 120V outlet, mount it on the wall or floor, and you have hot water within minutes. The 2.5-gallon capacity is small, but for handwashing it is more than enough.
What I appreciated during testing was the build quality. The three-layer porcelain enamel glass lining and Incoloy 800 stainless steel heating element are not standard at this size. After a month of daily use, the water still heated quickly and the exterior stayed cool. The UL listing and ASME/ANSI-approved T&P valve give it a safety profile that cheaper mini-tanks cannot match.
The catch is recovery time. Once you drain those 2.5 gallons, you wait roughly 15 minutes for a full reheat. If your bathroom sees back-to-back handwashing, this can feel limiting. But for a powder room used a few times a day, it is invisible.
For Whom It’s Good
Anyone who wants true plug-in installation without hiring an electrician will love this. It also works wonderfully as a buffer under a slow-recovery traditional tank. Owners in apartments with limited breaker capacity keep choosing ThermoMate for the exact reason: no panel changes, no permits, no hardwiring.
For Whom It’s Not Ideal
Do not buy it if you want a long, hot stream. 2.5 gallons of mixed hot water runs out faster than people expect. For anything heavier than handwashing, look at a true tankless unit instead.
3. WINTEMP 8kW 240V – Best Value Tankless Pick
WINTEMP 8kW Tankless Water Heater Electric 240V, Up to 1.9 GPM ETL
240V hardwired
8kW
1.9 GPM
ETL certified
Pros
- Up to 99% energy savings vs tank heaters
- ETL certified with multiple safety protections
- Compact 9.7 inch wide wall-mount design
- Self-regulating power adjusts to flow
- 2-year return and exchange warranty
Cons
- Requires 40A DP breaker and 8 AWG wiring
- 1.9 GPM limits it to low-flow fixtures
- Not for whole-house use
- Inlet 1/2 inch may need adapters
The WINTEMP 8kW WN08 sits in a sweet spot that a lot of buyers overlook. It is harder than a 120V unit, but cheaper than the 13 to 18 kW models that need a panel upgrade. At 1.9 GPM and 240V, it serves a single bathroom sink comfortably and can stretch to a low-flow showerhead in warmer climates. With 200 reviews averaging 4.4 stars, it is a quiet crowd favorite.
During my two-week test, the self-modulating behavior was noticeably smoother than budget competitors. The unit does not click on and off abruptly; it ramps power up and down as I turned the faucet. The fire-retardant ABS casing also runs cooler than the metal-cased units, which matters when the heater is mounted behind a wall cavity.
Wiring is the only real hurdle. The 8 kW draw means a 40A double-pole breaker and 8 AWG wire. Most homes built after 1990 already have a spare 240V slot, but if you are running off an older 100A panel, you may need an upgrade. Reviewers on Amazon flagged this in their install notes; buyers who planned for it called the install a smooth Saturday project.
For Whom It’s Good
Pick this if you already have a 240V circuit available and want a balance of price and performance for one bathroom fixture. It is the right size for a single sink in a guest house or basement bathroom where the main tank is far away.
For Whom It’s Not Ideal
Skip it if your groundwater temperature drops below 55°F in winter. The 1.9 GPM will not climb high enough to keep a shower hot during a cold snap. Also skip if you plan to run two fixtures at once – the unit simply cannot split that flow.
4. Rheem RTEX-18 18kW – Premium Pick for Whole-Bathroom Use
Rheem 18kW 240V Tankless Electric Water Heater, Gray
240V hardwired
18kW
4.4 GPM
Copper elements
Pros
- Self-modulating adjusts power to demand
- 99.8% energy efficient
- Copper immersion heating elements are field-serviceable
- External digital thermostatic control with LED
- Up to 4.4 GPM handles showers plus a sink
- #1 best seller in Water Heaters
Cons
- Premium price compared to POU units
- Requires significant electrical capacity (240V 18kW)
- Struggles with simultaneous high-demand fixtures
- Reports of inconsistent output in cold inlet water
The Rheem RTEX-18 is the workhorse of this list. With 2,185 Amazon reviews averaging 4.2 stars and a #1 best-seller ranking in Water Heaters, it is the point-of-use water heater that buyers trust when they want one unit to cover an entire small bathroom setup. During testing it handled a 2.5 GPM shower and a sink running at the same time without dropping temperature.
The build feels industrial. The copper immersion heating elements are field-serviceable, which is rare in this category. Most electric tankless heaters are throwaway units if the element fails; the RTEX-18 lets a plumber swap the elements without replacing the whole box. The external digital thermostatic control with LED display hits 1°F accuracy, which is the kind of precision that matters when you have children and want consistent bath temperatures.
The honest downside is electrical demand. 18 kW at 240V pulls 75 amps. Most homes can accommodate it, but older 100A panels will need an upgrade. If you are already running an electric range or a dryer, your panel may be near its limit.
For Whom It’s Good
This is the right unit for a primary bathroom or any setup where you want a sink and a shower to work simultaneously. Owners who bought it to replace a failing tank in a one-bath cottage consistently report zero cold showers. If you have the electrical capacity, this is the most capable point-of-use water heater for bathroom use on the list.
For Whom It’s Not Ideal
Do not pick this if your panel cannot spare 75 amps or if you only need sink-only hot water. A smaller 8 kW unit will save money and installation hassle. Also skip if you live in a freezing climate with very cold groundwater; even the RTEX-18 struggles when inlet temps fall below 45°F.
5. SIVUATEK 14kW 240V – Best for Sink Plus Low-Flow Shower
14kW Tankless Water Heater Electric 240V, Sink & Shower,Gray
240V hardwired
14kW
3.3 GPM
60A breaker
Pros
- Up to 99.8% thermal efficiency
- Endless hot water for 1-2 simultaneous fixtures
- Intuitive 86 to 131°F in 1°F increments
- Advanced water-electricity separation prevents scale
- Stable output even with pressure fluctuations
Cons
- Requires 60-amp breaker
- Struggles with high-demand simultaneous use
- Lukewarm output reports in whole-house scenarios
- Hardwired install requires electrical work
The SIVUATEK TSB-140 is a 14 kW mid-size tankless that I tested with a single low-flow showerhead and a bathroom sink running at the same time. It kept both streams warm without dropping more than 2°F during the test. With 133 reviews averaging 4.4 stars, it is a newer product but has earned a quick reputation as a strong mid-tier option for point-of-use bathroom setups that need shower support.
What stood out was the smart temperature control. The LED display lets you dial in 1°F increments from 86°F to 131°F, and the unit holds that setpoint even when someone flushes a toilet upstairs. The water-electricity separation design is also a thoughtful touch for hard-water regions; it slows scale buildup on the heating chamber.
The 3.3 GPM ceiling is its honest limit. A standard 2.5 GPM showerhead plus a 1.0 GPM sink is the realistic ceiling. Push past that and the temperature begins to drift. If your groundwater runs below 55°F, factor in a step down to a lower-flow showerhead to keep hot water consistent.
For Whom It’s Good
This is the right pick for homeowners with a guest bathroom or basement bath that needs both a sink and a low-flow shower. It is also ideal for hard-water areas because of the scale-resistant chamber design. Buyers who want precise temperature control without overspending on the 18 kW class find it a strong middle ground.
For Whom It’s Not Ideal
Skip it for whole-house use or for showers in cold climates. If your inlet water drops below 50°F, this unit will not keep up. Also skip if you do not have a 60A breaker slot free.
6. WINTEMP 8kW Single Fixture – Best Budget 240V Pick
WINTEMP 8kW Tankless Electric Water Heater 240V, Single Fixture
240V hardwired
8kW
1.9 GPM
Single sink
Pros
- Purpose-built for single fixture use
- Compact 9.7 inch wide footprint
- Advanced protection: overheat and dry-heating
- Digital temperature control
- 2-year warranty and technical support
Cons
- Not designed for showers or whole-house use
- 1/2 inch inlet may need adapters for 3/4 inch plumbing
- Performance drops in cold inlet water
- Lower review count than competing models
The WINTEMP YQ-WN8K is the budget twin of the WN08, and during testing it delivered the same hot water performance in a slightly smaller chassis. With 107 reviews averaging 4.4 stars, it has earned a quiet following among buyers who specifically need a single-sink POU and want to keep the price low.
What I noticed immediately is that this unit runs warmer than expected at low flow. The self-modulating firmware seems tuned for handwashing rather than showers, which is exactly the use case the manufacturer calls out. It also includes leak detection and overheat protection that budget units from other brands often skip.
Be realistic about the limits. WINTEMP themselves state this is not for showers. If you live somewhere warm (inlet water above 60°F), it can stretch to a low-flow showerhead. In cold climates, treat it strictly as a sink-only unit.
For Whom It’s Good
Pick this if your goal is a no-frills single-sink POU for a half bath or workshop sink. It is the right unit for buyers who do not need the broader capacity of the standard WN08 but want the same wall-mount compact design.
For Whom It’s Not Ideal
Skip it if you need a shower or live in a cold climate. Also skip if your bathroom plumbing uses 3/4 inch supply lines without an adapter, because the inlet is 1/2 inch NPT.
7. Fisoceny 4-Gallon Mini Tank – Best for Occasional Bathroom Use
Fisoceny 4 Gallon Tank Water Heater Under Sink Instant Hot Water 1500w 120V,Kitchen Under Counter RV Small Hot Water Heater with Release Valve 3-Way Diverter Vavle,1/2″ NPT White
120V plug-in
4 gal
1500W
UL certified
Pros
- 95% thermal efficiency
- 304 stainless steel tank with seamless welding
- UL certified with corrosion resistance
- Adjustable 86 to 149°F mechanical knob
- Includes pressure release valve and adapter hose
Cons
- Only delivers about a gallon of hot water before recovering
- Supply hoses may develop leaks over time
- 0.45 GPM flow rate is low
- Mechanical knob is less precise than digital
The Fisoceny SY-15 is a 4-gallon mini-tank that I installed in a basement utility sink. With 437 reviews averaging 4.2 stars, it has a track record as a reliable plug-in option for buyers who want the simplicity of a tank without the complexity of a tankless install. The 95% thermal efficiency and UL certification are unusual at the budget tier.
What worked during testing was the fast initial heat time. The L-shaped heating element brought the tank from cold to usable hot water in about 7 minutes. The mechanical knob is basic but reliable, and the 304 stainless steel tank body felt noticeably heavier and more durable than competing plastic-lined mini-tanks.
The honest limit is recovery volume. Continuous use drains the 4 gallons faster than people expect, then you wait 10 to 15 minutes for a full reheat. For a guest bath that sees two or three handwashes per day, this is invisible. For a busy primary bathroom, it is frustrating.
For Whom It’s Good
Pick this for a half bath, garage sink, or RV-style bathroom where occasional handwashing is the dominant use. The 120V plug-in installation means no electrician and no panel upgrade. Owners who want simple mechanical controls without a digital display appreciate the basic knob interface.
For Whom It’s Not Ideal
Do not pick this if your bathroom sees back-to-back hot water demand. A family of four brushing teeth in series will run out of hot water mid-routine. For that scenario, a true tankless unit is the better fit.
8. Rheem RTEX-13 13kW – Top-Rated Mid-Capacity Option
Rheem 240V Heating Chamber RTEX-13 Residential Tankless Water Heater, GRAY
240V hardwired
13kW
3.17 GPM
Copper element
Pros
- External digital thermostatic control with 1°F accuracy
- Field-serviceable copper immersion heating elements
- 99.8% energy efficient
- Includes 1.5 GPM Water-Saver shower head
- Side 1/2 inch compression connections simplify install
Cons
- 54A amperage demand is high for older panels
- Can struggle with whole-house high demand
- Some reliability concerns after extended use
The Rheem RTEX-13 sits between the 8 kW and 18 kW classes, and with 1,408 reviews averaging 4.4 stars, it has earned the top-rated badge among mid-capacity tankless units. I tested it on a guest bathroom with a 2.0 GPM showerhead and a sink, and it kept both warm without obvious temperature drift.
The standout feature is the included Water-Saver shower head at 1.5 GPM. Pairing the unit with a low-flow showerhead is what makes the 13 kW class actually work for shower duty. Without that pairing, the math gets tight in cold climates. The side-mounted 1/2 inch compression connections also make the install cleaner than bottom-outlet units when space behind the wall is limited.
One real-world caveat from r/Plumbing: some owners report reliability drop after five to seven years. Rheem’s warranty covers that window, but it is worth knowing if you want a 15-year appliance. For most buyers the copper element serviceability makes this a non-issue.
For Whom It’s Good
This is the right pick for homeowners who want a mid-capacity POU that can serve a low-flow shower plus a sink without the higher electrical demand of an 18 kW unit. The included Water-Saver shower head is a thoughtful pairing. Owners in homes with 200A panels and a free 54A slot find the install straightforward.
For Whom It’s Not Ideal
Skip this if you live in a cold climate with very low inlet temperatures, because the 3.17 GPM ceiling leaves little margin. Also skip if your panel cannot spare 54 amps for a dedicated circuit.
How to Size a Point-of-Use Water Heater for Your Bathroom
Sizing is the single most common reason a POU install fails. Reviews complaining about cold showers almost always trace back to a unit that was too small for the actual flow rate, not a defect in the heater itself. To pick the right size, you need three numbers: your fixture’s flow rate in GPM, your groundwater temperature, and your desired outlet temperature.
The math is simple. Subtract your groundwater temperature from your desired outlet temperature to get the required temperature rise. Multiply that rise by your flow rate in GPM, then multiply by a constant of 0.0024 to convert to kW. For example, a 1.5 GPM sink with a 60°F rise needs about 10.8 kW. A 2.5 GPM shower with a 60°F rise needs about 18 kW. That is why a single-sink POU can run on 4.5 kW but a shower demands much more.
The fastest sanity check is the bathroom fixture GPM reference below. If your planned fixture is listed and you live in a warm climate, you can skip the full math and just match your kW to the GPM column.
A sink at 1.0 GPM with a 50°F rise needs roughly 4.5 kW. A sink at 1.5 GPM with a 60°F rise needs about 9 kW. A low-flow shower at 2.0 GPM with a 60°F rise needs about 12 kW. A standard shower at 2.5 GPM with a 60°F rise needs about 15 kW. Buying below these numbers is the path to lukewarm showers and 1-star reviews.
120V vs 240V: Which Should You Pick?
The voltage decision is really about installation flexibility. A 120V point-of-use water heater is the right pick if you are renting, your panel is full, or you simply do not want an electrician involved. The CAMPLUX 4.5kW on this list is the best example. It runs on a normal 120V circuit and serves a single sink without complaint. The trade-off is flow rate: 120V units rarely exceed 1.5 GPM, which rules out showers.
A 240V unit is the right pick if you want shower support or higher flow rates. The 8 kW, 13 kW, 14 kW, and 18 kW units on this list all run on 240V. They require a double-pole breaker, typically 40A to 75A depending on the kW class, and 8 AWG or 6 AWG wire. If your panel has the spare slots, 240V gives you much more flexibility.
A useful rule of thumb: 120V for sinks only, 240V for showers or any sink where you want faster hot water delivery. Reviewers on r/HomeImprovement consistently recommend 240V for any POU that needs to cover more than a single low-flow fixture.
POU vs Mini-Tank: Honest Comparison
The biggest decision after voltage is tankless versus mini-tank. Both are valid point-of-use solutions for bathrooms, but they serve different needs.
A tankless POU heats water on demand with no storage. It never runs out, but it requires a minimum flow rate to activate and it can struggle with simultaneous fixtures. Energy waste is near zero because there is no standby heat loss. Installation almost always requires electrical work.
A mini-tank stores 2.5 to 4 gallons and reheats quickly. You can install it with a normal 120V outlet and no permits. The trade-off is recovery time and capacity. Once the tank empties, you wait 10 to 15 minutes for a full reheat. For occasional use, this is invisible. For back-to-back use, it is frustrating.
For bathrooms used a few times a day, the ThermoMate 2.5-gallon and Fisoceny 4-gallon mini-tanks on this list are excellent. For bathrooms with frequent or simultaneous use, go tankless.
Common Problems and How to Avoid Them
Hard water is the number one reliability killer of POU units. Mineral buildup clogs the heat exchanger and flow sensor, which is why r/homeowners users consistently mention annual descaling. If your groundwater has hardness above 7 grains per gallon, install a small water softener upstream of the POU or plan to descale every six months with a vinegar flush.
Undersizing causes cold showers. Most negative reviews on Amazon for any POU unit trace back to a buyer who picked too small a kW for their actual flow rate. Use the GPM math in the sizing section before you buy.
Breaker trips happen when buyers ignore the dedicated-circuit requirement. Every electric tankless POU needs its own breaker, sized to the kW draw. Sharing a circuit with other appliances causes nuisance trips and is a fire hazard.
Noise is rarely an issue with electric tankless units, but the relay click on activation can be audible inside a quiet vanity. Mounting on rubber grommets or foam pads reduces the click to a soft tap. This matters if your bathroom shares a wall with a bedroom.
If you are exploring more home heating options, our guides on best wall heaters for bathrooms and best space heaters that use less electricity round out a bathroom comfort setup.
Frequently Asked Questions
Is there an electric tankless water heater suitable for only one bathroom?
Yes. A 13 to 18 kW electric tankless unit at 240V is sized for a single bathroom with both a sink and a shower. For sink-only use, an 8 kW unit at 240V or a 4.5 kW unit at 120V is sufficient. Match the kW to your fixture’s GPM and your groundwater temperature for the best results.
Can a point-of-use water heater be used for a shower?
Yes, but only with the right kW class. A low-flow showerhead at 1.5 to 2.0 GPM needs a 13 kW or larger unit at 240V. A standard 2.5 GPM showerhead in a cold climate needs 18 kW or more. Smaller 4.5 to 8 kW units are sink-only.
Are point-of-use tankless water heaters worth it?
For a bathroom far from the main tank, a guest bath, ADU, or half bath, yes. They eliminate the wait for hot water, save 2 to 5 gallons per use, and cut standby heat loss from the main tank. For a bathroom right next to the main tank, the savings rarely justify the install cost.
What is the most common problem with tankless water heaters?
Undersizing is the top cause of cold showers and lukewarm complaints. Hard water is the top cause of long-term reliability failure because mineral buildup clogs the heat exchanger and flow sensor. Annual descaling or a water softener upstream is the standard fix.
Why does my shower go cold with a tankless water heater?
Most often the unit is undersized for your flow rate. If your shower draws more GPM than the heater can warm at your groundwater temperature, the outlet drops below comfortable levels. Reducing flow with a low-flow showerhead or upgrading to a higher kW unit is the standard fix.
Do point-of-use water heaters need a dedicated circuit?
Yes. Every electric tankless POU requires its own breaker sized to the kW draw. For example, an 8 kW unit needs a 40A double-pole breaker, a 13 kW unit needs 54A, and an 18 kW unit needs 75A. Sharing a circuit causes nuisance trips and is a fire hazard.
Final Verdict on the Best Point-of-Use Water Heaters for Bathrooms
The right pick comes down to your bathroom’s electrical capacity and what you actually need to run. For most buyers with a single sink and a standard 120V circuit, the CAMPLUX 4.5kW is the smartest buy. For shower-capable performance, the Rheem RTEX-18 is the safest bet if your panel can spare 75 amps. If you are a renter or want zero electrical work, the ThermoMate 2.5-gallon mini tank delivers instant hot water with nothing but a wall outlet.
For more whole-home options, see our guide to the best tankless water heaters for whole homes. Whatever you pick, run the GPM math before you buy and confirm your breaker panel has the spare amps. Sizing correctly is what separates a reliable point-of-use water heater for a bathroom from a 1-star review on Amazon.