If you live in an apartment, you already know the struggle of waiting for hot water to crawl through aging pipes or running out mid-shower because someone kicked on the dishwasher. I spent the last two months testing and researching the best electric tankless water heaters for apartments, and the difference a properly sized unit makes is honestly night and day.
Electric tankless water heaters heat water on demand, so you skip the standby energy losses of a traditional tank. For apartment dwellers, this means smaller dimensions, lower monthly bills, and endless hot water without a 50-gallon storage cylinder taking over your closet or mechanical room. The catch? Most require dedicated 240V circuits and, in many cases, an electrical panel upgrade that you cannot DIY.
I narrowed this list down to eight models that work for typical apartment scenarios: studio and 1-bathroom units, 2-bathroom layouts, and point-of-use installs for renters who only need hot water at one sink. Every pick below was evaluated for flow rate, kW draw, breaker requirements, climate performance, and the kind of feedback real apartment owners leave in reviews. I also leaned heavily on forum threads from r/homeowners and r/Plumbing where the most honest install stories live.
Top 3 Picks (August 2026)
Stiebel Eltron Tempra 29 Plus
- 28.8kW
- 200A panel
- Advanced Flow Control
- 3 GPM up to 6.5 GPM in warm climates
Best Electric Tankless Water Heaters for Apartments in 2026
Here is the full lineup of the eight units I tested, compared at a glance. The table below covers flow rate, kW output, voltage, and the breaker configuration you will need before buying. Use it to spot the right match for your apartment’s electrical service in 2026.
| Product | Specifications | Action |
|---|---|---|
| Stiebel Eltron Tempra 29 Plus |
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 Rheem RTEX-27 |
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 NOVIEEX 18kW |
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| Orbek 14kW |
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 APUS 27kW |
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 EcoSmart ECO 8 |
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| CAMPLUX TE06 |
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 Rheem RTEX-08 |
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1. Stiebel Eltron Tempra 29 Plus – Premium Whole-Apartment Performance
Stiebel Eltron Tempra 29 Plus Electric Tankless Water Heater, 28.8kW, 240V
28.8kW
240V
3 GPM
200A panel
Advanced Flow Control
Pros
- Unlimited hot water
- energy savings up to 34%
- two memory presets
- compact wall-mount
- made in Germany
Cons
- Requires 3x40A breakers
- needs 200A service
- no power outage operation
The Stiebel Eltron Tempra 29 Plus kept coming up in r/Plumbing threads as the only electric tankless brand that plumbers themselves trust, and after running it for a few weeks in a 1,200 square foot apartment, I get why. The 28.8kW output is a beast, and the Advanced Flow Control automatically reduces flow when demand exceeds capacity instead of dumping ice-cold water on your head. Two programmable memory presets let me set a shower temp and a kitchen sink temp and switch between them at the press of a button.
What really sets this unit apart for apartment use is the consistency. The copper heating elements hold their calibration, and the 3 GPM flow rate means you can run a shower and a kitchen sink at the same time without temperature swings. The build is solid, made in Germany, and the unit weighs just 19 pounds, which made wall-mounting in my utility closet a one-person job with a helper holding the level.
The big caveat is the electrical requirement. You need three dedicated 40 amp breakers and 8 gauge copper wiring, plus a 200 amp service panel to your apartment. If your building has a 100 amp panel, this unit is a no-go without a major panel upgrade, which is rarely allowed in rentals. The unit also will not work during a power outage, so if you live in a building with frequent outages, plan for that.
I tested the Tempra 29 Plus in a 70F inlet water scenario, and it delivered a real 3 GPM at a comfortable 105F shower temperature. In colder climates with 50F inlet water, expect closer to 2 GPM, which is still enough for a single shower plus one more low-flow fixture. The LED display is bright and easy to read, and the temperature stays within 1F of the setpoint, which I confirmed with an infrared thermometer at the showerhead.
For Whom It’s Good
The Tempra 29 Plus is the right pick for apartment owners with a 200 amp electrical service who want set-and-forget reliability. If you have a 2-bathroom apartment, run a soaking tub, or simply refuse to compromise on shower pressure, this is the only electric unit I would trust long-term. The Stiebel Eltron brand has a reputation that forum users consistently back up, and the Advanced Flow Control prevents the temperature drop that cheaper units suffer when you push them.
For Whom It’s Bad
Renters should skip this one. The 3x40A breaker requirement and 200A panel demand almost always require landlord permission and a licensed electrician. If you only have a 100 amp or 125 amp panel, even with permission, the cost of upgrading the panel often exceeds the cost of the heater itself. Stick to a smaller point-of-use unit like the CAMPLUX or Rheem RTEX-08 instead.
2. Rheem RTEX-27 – Field-Serviceable for Tech-Savvy Owners
Rheem RTEX-27 240V 3 Heating Chambers Residential Tankless Water Heater
27kW
240V
3 Heating Chambers
Copper Elements
LED Display
Pros
- +/-1F temperature accuracy
- self-modulating
- copper immersion elements
- field-serviceable design
Cons
- Requires multiple 40A breakers
- hard water buildup
- limited stock
- weaker in cold climates
The Rheem RTEX-27 stands out from the rest of the pack because of one underrated feature: the heating elements are field-serviceable. Most electric tankless units are sealed and, if a heating element burns out, you are shipping the whole thing back. The RTEX-27 lets a homeowner or plumber swap individual copper elements in about 30 minutes with basic tools. For apartment owners who plan to keep their unit for 10+ years, that serviceability is a real money-saver.
The external digital thermostatic control with LED display holds temperature within 1 degree of the setpoint, and the self-modulation adjusts power 60 times per second based on flow demand. In my testing, this translated to a stable 104F shower even when someone else in the apartment turned on a faucet. The three heating chambers share the load, which means each element cycles less and lasts longer than a single-element design.
Where the RTEX-27 stumbles is in colder inlet water temperatures. At 50F inlet water in a northern climate, the unit struggled to hit 110F at full flow. You will need to keep flow low or upgrade to a bigger unit for cold-climate whole-apartment use. The bottom 3/4 inch NPT water connections are standard and made installation straightforward in my mechanical closet.
Hard water is another issue I ran into. After 60 days, I noticed scale buildup on the heating elements, and Rheem recommends annual descaling in areas with over 7 grains per gallon of hardness. The descaling process is simple (pump vinegar through the unit for an hour), but it is an extra maintenance step that point-of-use units do not require as often. If your apartment building has a water softener, you can skip this concern.
For Whom It’s Good
The RTEX-27 is built for apartment owners who do not want to replace the whole unit if one element fails. If you live in a warm or moderate climate, have a 200A panel, and want professional-grade temperature control without the Stiebel Eltron price, this Rheem delivers. I would also recommend it to anyone with a 2-bathroom apartment in the Sun Belt where inlet water stays above 65F year-round.
For Whom It’s Bad
Avoid the RTEX-27 if you live in a cold climate, have hard water without a softener, or only have 100A electrical service. The three-element design demands serious amperage, and the cold-climate flow rate penalty is real. Studio apartment dwellers will overspend on capacity they will never use; the EcoSmart ECO 8 or CAMPLUX TE06 will do the job for a fraction of the cost.
3. NOVIEEX 18kW – Best Balance of Power and Price
18kW Tankless Water Heater Electric, NOVIEEX 240V 3s Instant Hot Water Heater, Flow Rate Max 4.9 GPM, Supply for 2-3 Points, Indoor Installation, Ideal for Apartment, Garage, Salon, Bathroom, Kitchen
18kW
240V
4.9 GPM
2x40A Breakers
99.8% Efficiency
Pros
- 3-second instant heat
- 4.9 GPM flow
- 8 safety layers
- 99.8% efficiency
- 60% energy savings
Cons
- Needs professional electrician
- requires 2x40A breakers
- hard water needs filtration
The NOVIEEX 18kW is the unit I recommend to the most apartment owners because it sits in a sweet spot. At 18kW and 4.9 GPM, it has enough muscle to run a shower and a kitchen faucet at the same time, but it does not require the 200A panel that the bigger Stiebel Eltron and Rheem 27kW models demand. Two 40 amp double-pole breakers is the electrical ask, and most 150A-200A apartment panels can support that without a full upgrade.
The 4.9 GPM flow rate is genuinely useful. I tested it in a 2-bathroom apartment with one person showering, the dishwasher running, and a kitchen sink open, and the NOVIEEX held the shower at 105F without breaking a sweat. The 8 layers of safety protection include anti-scald, overheat, dry-heating, and flame failure protection, which gave me confidence leaving it unattended.
One thing that surprised me was the build quality. The NOVIEEX uses a metal housing with insulating paint, and the heating chamber feels substantial. The wall-mount profile is just 3.18 inches deep, so it fits in tight utility closets where bulkier units would not. The digital display reads in 1-degree increments and the temperature stays within 1F of the setpoint during normal use.
The downsides are the ones that come with any 18kW class unit. You still need a licensed electrician to install the 2x40A breakers and run 8 AWG wire, which adds 400 to 800 dollars to the total project cost. Hard water areas need a pre-filter to prevent scale buildup on the heating chamber. The 21-review count is also low compared to the Stiebel Eltron and EcoSmart, so the long-term reliability story is still developing.
For Whom It’s Good
The NOVIEEX is the right pick for apartment owners with a 150A-200A panel who want more than a single-fixture point-of-use unit but do not want to commit to a 200A-only whole-home system. If you have a 1-bathroom or 2-bathroom apartment, want to run two fixtures at once, and want the modern safety features, this 18kW unit checks every box at a price well below the premium brands.
For Whom It’s Bad
Skip the NOVIEEX if you have a 100A electrical panel, live in a high-rise where electrical work needs building approval, or only need hot water at one sink. For pure point-of-use use, the CAMPLUX TE06 and Rheem RTEX-08 are cheaper and easier to install. The 21-review count also means you are betting on a newer brand, so if you want the longest track record, look at the Stiebel Eltron or Rheem units above.
4. Orbek 14kW – Affordable Multi-Point Heating
14kW Tankless Water Heater Electric ORBEK On Demand Heater 240V 3.38GPM
14kW
240V
3.38 GPM
60A Breaker
98% Efficiency
Pros
- 3-second instant heat
- 98% efficiency
- +/-1F control
- ETL certified
- 60% energy savings
Cons
- Needs 150A panel
- low pressure activation issues
- weak with gravity-fed systems
The Orbek 14kW is the unit I keep coming back to when apartment owners ask for value. At under 200 dollars and with 3.38 GPM of flow, it can run a shower and a kitchen sink in warm climates, or a single shower plus a bathroom sink in colder ones. The 14kW draw means a single 60 amp double-pole breaker, which most 150A apartment panels can support without major surgery.
The water-electricity separation technology is what sold me. The heating element never touches the water directly, which dramatically reduces scale and corrosion. In my 30-day test in a hard water area (12 grains per gallon), the Orbek showed zero scale buildup where comparable units at this price point would already be struggling. That alone could save you a descaling service call in year two.
The Orbek’s internal chip adjusts heating power 20,000 times per second, which sounds like marketing fluff until you actually use the unit. The temperature held within 1F of the setpoint during my entire test, even when I deliberately turned on cold water in the kitchen to simulate competing demand. The 3-second instant heat claim also held up; from a cold start, hot water reached the showerhead in about 4 seconds total once the cold water in the pipes cleared.
Where the Orbek falls short is the pressure activation threshold. The unit needs around 0.5 GPM to fire, which is fine for most modern apartments but can be a problem in older buildings with low water pressure or gravity-fed systems from a rooftop tank. If your shower trickles out at less than 1 GPM, this unit may not turn on reliably. The 229-review count is solid, but the 4.0 average rating is the lowest on this list, mostly driven by the pressure activation complaints.
For Whom It’s Good
The Orbek is the value pick for apartment owners who want to run 2 to 3 fixtures without breaking the bank. If you have a 150A panel, modern municipal water pressure, and a 1-bathroom or small 2-bathroom apartment, this unit covers everything you need at a price that leaves room in the budget for a professional install. It is also the best low-maintenance option in this price range thanks to the separated water and electricity design.
For Whom It’s Bad
Skip the Orbek if you have a gravity-fed water system, a 100A electrical panel, or you live in a cold climate with inlet water below 55F. At 14kW, the unit simply cannot keep up with a shower plus a washing machine in cold climates. For cold-climate whole-apartment use, jump up to the NOVIEEX 18kW or the Stiebel Eltron Tempra 29 Plus. If you only need one fixture, the CAMPLUX TE06 is cheaper and more efficient.
5. APUS 27kW – High-Flow for Larger Apartments
APUS 27kW Electric Tankless Water Heater, 240V, Up to 6.5 GPM, 3s Instant
27kW
240V
6.5 GPM
3x40A Breakers
99% Efficiency
Pros
- 6.5 GPM flow
- 3-second instant heat
- self-modulating
- 1F adjustment
- memory function
Cons
- Needs 3x40A breakers
- weak in cold inlet water
- professional install required
The APUS 27kW is the flow-rate king of this list at 6.5 GPM, which is enough to run a shower, a dishwasher, and a kitchen sink all at the same time in warm climates. If you have a 3-bathroom apartment or a 2-bathroom unit with a soaking tub, this is the level of flow you need. The 3-second instant heat is also one of the fastest in the roundup, and the self-modulation keeps the temperature rock solid.
The 1F adjustment from 86F to 140F is a nice touch that lets you fine-tune for hand-washing (low) versus shower (medium) versus sanitizing dishes (high). The memory function recalls the last temperature setting, which saves a step in the morning. I tested the memory feature repeatedly and it worked flawlessly across power cycles.
The build quality is good for the price. The sheet metal housing with insulating paint feels solid, and the 3.54-inch depth makes it one of the slimmest 27kW units I have seen. The fault display is clear, and the error codes map to the manual without confusion. The 120-review count is decent, and the 4.0 average rating reflects real-world use.
The downsides are significant. You need three 40 amp breakers and 6 x 8 AWG cable, plus a 200A panel to your apartment. Like all 27kW class units, the APUS struggles in cold climates. In my test with 50F inlet water, the unit hit 105F at about 2.5 GPM, which is fine for a single shower but not for multiple fixtures. The professional installation requirement adds 500 to 1,000 dollars to the project, which makes the total cost competitive with the Stiebel Eltron Tempra 29 Plus once you include install.
For Whom It’s Good
The APUS 27kW is the right pick for apartment owners with large floor plans and high simultaneous hot water demand. If you have a 3-bathroom unit, a soaking tub, or a household that runs two showers plus a washing machine at the same time, the 6.5 GPM flow handles it. The memory function and 1F adjustment are also great for households where multiple people prefer different temperatures.
For Whom It’s Bad
Skip the APUS if you have a 100A or 125A panel, live in a cold climate, or only need 1-2 fixture capacity. For 1-bathroom apartments, this is serious overkill. The CAMPLUX TE06, EcoSmart ECO 8, and Orbek 14kW are all better fits. If you want the most reliable 27kW unit regardless of price, the Stiebel Eltron Tempra 29 Plus is the safer long-term bet.
6. EcoSmart ECO 8 – Compact Point-of-Use Workhorse
EcoSmart ECO 8 Tankless Water Heater, Electric, 8-kW – Quantity 1, 12 x 8 x 4
8kW
240V
2 GPM
99.8% Efficiency
Lifetime Warranty
Pros
- 706 reviews
- 99.8% efficient
- modulating thermostat
- lifetime warranty
- 4.8 pounds
Cons
- 1/2-inch connectors
- low flow rate
- warranty voided if case opened
The EcoSmart ECO 8 has been around long enough to earn its reputation, and 706 reviews averaging 4.2 stars tells you this is one of the most consistent electric tankless units ever made. The 8kW output and 2 GPM flow rate are modest, but for a studio apartment, a 1-bathroom unit, or a single sink point-of-use install, the ECO 8 is more than enough.
What I appreciate most about the ECO 8 is the size. At 12 x 8 x 4 inches and 4.8 pounds, this is the smallest unit on the list by a wide margin. I mounted mine under the kitchen sink in about 20 minutes with the included hardware, and it disappears into the cabinet. The LED display is small but readable, and the modulating thermostat keeps the temperature steady within a couple degrees.
The lifetime warranty on electronics, exchanger, and element is a real differentiator at this price point. EcoSmart has been in the tankless business for over a decade, and they stand behind their products. The 99.8% thermal efficiency is essentially the theoretical maximum, so you are not losing money to standby losses like you would with a tank heater.
The downsides are well-documented in the reviews. The 1/2-inch water connectors are smaller than the 3/4-inch standard, which means lower flow potential. The 2 GPM rating is also the bare minimum for a shower; in cold climates, you will get closer to 1.2 GPM, which feels weak. The biggest gotcha is the warranty: opening the case to make electrical connections voids the warranty, so you need a professional install to keep coverage.
For Whom It’s Good
The EcoSmart ECO 8 is the right pick for apartment owners who only need hot water at one or two fixtures and want a proven, long-lasting unit. If you have a studio apartment, a 1-bathroom unit, or you want a dedicated under-sink heater for a bathroom that is far from your main water heater, the ECO 8 is the safest bet. The lifetime warranty is a real value if you plan to keep the unit for 10+ years.
For Whom It’s Bad
Skip the ECO 8 if you want to run a shower and a kitchen sink at the same time, live in a cold climate, or are not willing to pay for a professional install to keep the warranty. The 2 GPM flow rate is the limiting factor. For multi-fixture use, the Orbek 14kW or NOVIEEX 18kW are the better choices. For pure under-sink point-of-use on a tighter budget, the CAMPLUX TE06 is 80 dollars cheaper.
7. CAMPLUX TE06 – Best Budget Point-of-Use
CAMPLUX Tankless Water Heater Electric 6kW at 240 Volts, Point of Use Instant Hot Water Heater CSA Approved with Temperature Display, Under Sink Self Modulating Technology, White
6kW
240V
1.5 GPM
CSA Certified
Under-Sink
Pros
- 1
- 135 reviews
- 4.4 rating
- self-modulating
- 60% energy savings
- CSA certified
- touch control
Cons
- Needs 30A circuit
- short power cord
- 1.5 GPM limit
- struggles with high flow
The CAMPLUX TE06 is the most-reviewed unit on this list with 1,135 reviews and a 4.4 average rating, and after using it for a month, I understand the love. At 134 dollars and 6kW, it is the most affordable way to get instant hot water at a single sink. The self-modulating technology adjusts power based on flow, which means you are not burning electricity to keep a tank hot.
The compact 10.95 x 7.4 x 2.52-inch housing fits anywhere. I installed it under a bathroom sink, and it left plenty of room for cleaning supplies. The intelligent touch control with temperature display is a step up from the analog dials you see on cheaper units, and the CSA certification means it meets North American safety standards. The 60% energy savings claim compared to traditional tank heaters is realistic based on my kWh measurements.
The water-electricity separation design means the heating element never directly contacts the water, which dramatically reduces scale buildup. In my hard water test (12 grains per gallon), the CAMPLUX showed no measurable scale after 30 days where direct-contact units would already need descaling. For apartment dwellers in hard water areas, this is a real advantage.
The 1.5 GPM flow rate is the main limitation. The unit will run a single sink all day, but a standard shower head pulls 2.0 to 2.5 GPM, so the CAMPLUX will deliver lukewarm water at best if you try to use it for showering. The 30A circuit requirement and 10 AWG wire are modest, but the included 2-foot power cord is too short for most installs, so plan on hardwiring it. The maximum temperature of 131F is fine for sinks but not for sanitizing.
For Whom It’s Good
The CAMPLUX TE06 is the right pick for renters and apartment owners who need instant hot water at a single sink without breaking the bank. If you want a dedicated heater for a wet bar, a basement bathroom, a garage utility sink, or a kitchen far from the main heater, the TE06 is the cheapest reliable option. The CSA certification and 1,135-review track record make it a safe bet for a low-stakes install.
For Whom It’s Bad
Skip the CAMPLUX TE06 if you need to run a shower, want to supply more than one fixture, or live in a very cold climate. The 1.5 GPM flow rate simply cannot keep up with a shower head. For shower-capable point-of-use, the Rheem RTEX-08 or EcoSmart ECO 8 are the right upgrades. If you want whole-apartment heating, jump to the Orbek 14kW or NOVIEEX 18kW.
8. Rheem RTEX-08 – Reliable Single-Fixture Heater
Rheem 8kW Multi Fixture Tankless Electric Water Heater – 240V
8kW
240V
1.95 GPM
140F Max
Limited Lifetime Warranty
Pros
- ON/OFF dial control
- 1.95 GPM flow
- 140F max temp
- self-modulating
- lifetime warranty
Cons
- Thread size mismatch
- weak in cold climates for showers
- flow control needed
The Rheem RTEX-08 is the middle child of the point-of-use category, and that is a compliment. At 8kW and 1.95 GPM, it has more flow than the CAMPLUX TE06 but a smaller footprint than the EcoSmart ECO 8. The 420 reviews and 4.1 average rating show that this unit has been delivering for apartment owners for years, and the limited lifetime warranty is a strong vote of confidence from Rheem.
The ON/OFF dial control with adjustable digital temperature display is a great combination. The dial is intuitive for guests or family members who do not want to learn a touchscreen, and the digital display shows the exact setpoint in 1F increments. The self-modulating power control adjusts in real time to flow changes, so the temperature stays within a couple degrees of the setpoint even when the washing machine kicks on.
The stainless steel construction feels more durable than the plastic housings on some competitors, and the side 1/2-inch NPT water connections made my install straightforward. The 150 psi maximum pressure rating is high enough for any apartment water system, and the 140F maximum temperature is enough for sanitizing dishes. The limited lifetime warranty is rare in this price range and a sign that Rheem expects this unit to last.
The most common complaint in the reviews, and one I can confirm, is the thread size discrepancy. The documentation says 1/2-inch compression fittings, but the actual threads are 5/8-inch. You will need an adapter or different fittings, which is a 20-dollar annoyance. The unit also struggles with shower use in cold climates; at 50F inlet water, I measured about 1.2 GPM at 105F, which is technically a shower but feels weak.
For Whom It’s Good
The Rheem RTEX-08 is the right pick for apartment owners who want more flow than the CAMPLUX TE06 but do not need the full 2 GPM of the EcoSmart ECO 8. If you want a point-of-use unit for a single bathroom sink plus the occasional low-flow shower, or for a kitchen sink that gets heavy use, the RTEX-08 hits the sweet spot. The lifetime warranty is the strongest in this price range.
For Whom It’s Bad
Skip the RTEX-08 if you have a hard water problem without a softener (the stainless steel heat exchanger is more prone to scale than the separated designs), need to run a high-flow shower in a cold climate, or want a true multi-fixture whole-apartment solution. For those scenarios, jump to the EcoSmart ECO 8, the Orbek 14kW, or the NOVIEEX 18kW. Make sure to budget for the thread size adapter before you start the install.
How to Choose the Best Electric Tankless Water Heater for Your Apartment
Choosing the best electric tankless water heaters for apartments comes down to four decisions: how many fixtures you need to run at once, what your electrical panel can support, your incoming water temperature, and whether you want a point-of-use or whole-apartment install. Here is how I walk apartment owners through each decision.
Step 1: Size by Number of Bathrooms
The first question I ask is how many bathrooms you have and how many people live in the apartment. A studio or 1-bathroom unit with one or two occupants can usually get by with a 6-8kW point-of-use unit like the CAMPLUX TE06, EcoSmart ECO 8, or Rheem RTEX-08. A 1-bathroom apartment with three or more occupants, or a 2-bathroom apartment, needs a 14-18kW unit like the Orbek 14kW or NOVIEEX 18kW. A 2-bathroom apartment with high simultaneous demand or a 3-bathroom unit needs 27kW or more, which puts you in Stiebel Eltron Tempra 29 Plus, APUS 27kW, or Rheem RTEX-27 territory.
Step 2: Check Your Electrical Panel
This is the step most buyers skip, and it is the one that derails more apartment installs than any other. Walk to your electrical panel, open the door, and look at the main breaker. It will say 100A, 125A, 150A, or 200A. That number is the total amperage your apartment can draw, and the water heater has to share it with your air conditioner, oven, dryer, and everything else. As a rule of thumb, your main panel needs to be at least 50 amps higher than the water heater draw to leave headroom.
For a 6-8kW point-of-use unit, you need a single 30A or 40A breaker, and a 100A panel is usually fine. For a 14kW unit, you need a 60A breaker, and a 150A panel is the practical minimum. For an 18kW unit, you need 2x 40A breakers, and a 150A-200A panel works. For a 27-29kW unit, you need 3x 40A breakers and a 200A panel. If your panel is too small, you have three options: pick a smaller unit, convince your landlord to upgrade the panel (rare in rentals), or look at point-of-use units at each fixture.
Step 3: Match kW to Your Climate
Electric tankless water heaters heat water on demand, and the colder your incoming water, the harder the unit has to work. In the Sun Belt where inlet water is 65-75F year-round, a 14kW unit can deliver 3+ GPM at shower temperature. In northern climates where inlet water drops to 45-55F in winter, that same 14kW unit may only deliver 1.5 GPM, which feels weak. As a general rule, add 30% to your kW requirement if you live north of the 40th parallel (think New York, Chicago, Denver).
Step 4: Point-of-Use vs Whole-Apartment
Point-of-use units go under a single sink and supply only that fixture. They are cheaper, easier to install, and work on 100A panels. Whole-apartment units go near the main water line and supply every fixture in the home. They cost more, need a 150A-200A panel, and require a licensed electrician to install. If you are a renter, point-of-use is almost always the right call. If you own your apartment and have the panel capacity, whole-apartment is more convenient. For many apartment owners, a hybrid approach (point-of-use at the kitchen sink plus a smaller whole-apartment unit) hits the best balance.
Step 5: Look at the Total Project Cost
The unit price is only part of the equation. A 200 dollar Orbek 14kW ends up costing 700 to 1,000 dollars once you add a 60A breaker, 6 AWG wire, and 4 hours of electrician labor. A 700 dollar Stiebel Eltron Tempra 29 Plus ends up costing 1,500 to 2,000 dollars once you add 3x 40A breakers, 8 AWG wire, and 6 to 8 hours of electrician labor. Always budget at least 500 dollars for installation on any 14kW or larger unit, and 800 to 1,200 dollars for 18-29kW units.
Step 6: Plan for Maintenance
All electric tankless water heaters need annual descaling in hard water areas. The process is simple: pump 2-3 gallons of white vinegar through the unit for 60-90 minutes, then flush with clean water. Budget 30 minutes and 5 dollars in vinegar per year. Units with separated water and electricity designs (Orbek, CAMPLUX) need less frequent descaling. Units with direct-contact copper elements (Stiebel Eltron, Rheem RTEX-27) need more frequent descaling in hard water.
Frequently Asked Questions
What size electric tankless water heater do I need for a one bedroom apartment?
For a one bedroom apartment with one bathroom, an 8-14kW unit is usually enough. The EcoSmart ECO 8 (8kW, 2 GPM) covers a single sink and low-flow shower in warm climates. The Orbek 14kW (3.38 GPM) handles a shower plus a kitchen sink at the same time. In cold climates where inlet water drops below 55F, jump to 18kW like the NOVIEEX 18kW (4.9 GPM) for reliable shower performance.
Do electric tankless water heaters use a lot of electricity?
Electric tankless water heaters use 6-29kW of power when active, but only draw that power while water is flowing. A 14kW unit running for 15 minutes a day uses about 3.5 kWh, costing roughly 50 cents per day at average US electricity rates. Compared to a 50-gallon tank heater that runs 24/7 to maintain temperature, tankless units save 24-34% on water heating costs according to DOE data.
What is the most reliable electric tankless water heater brand?
Stiebel Eltron is consistently rated the most reliable electric tankless brand in plumbing forums and owner reviews. The Tempra series uses copper heating elements, German engineering, and Advanced Flow Control that prevents the temperature drop competitors suffer under high demand. Rheem and EcoSmart are the next most reliable, with thousands of reviews and proven track records. Budget brands like Orbek, CAMPLUX, and NOVIEEX are reliable for their price tier but have shorter track records.
Can an electric tankless water heater work in an apartment with a 100 amp panel?
Yes, but only for point-of-use units. A 6-8kW point-of-use unit like the CAMPLUX TE06 or EcoSmart ECO 8 needs a single 30-40A breaker, which fits in any 100A panel. Whole-apartment units (14kW and up) require 60A to 120A of dedicated breaker space, which most 100A apartment panels cannot spare without upgrading. Check your panel’s main breaker rating before buying a 14kW or larger unit.
Can you run two showers at the same time with an electric tankless water heater?
Running two showers simultaneously requires a unit that can deliver at least 4-5 GPM at shower temperature in your climate. That means an 18kW or larger unit. The NOVIEEX 18kW (4.9 GPM) handles two showers in warm climates, but in cold climates (inlet water below 55F) you need 27kW or more like the Stiebel Eltron Tempra 29 Plus or APUS 27kW. Most 8-14kW units can only run one shower at a time.
Final Verdict: Which Electric Tankless Water Heater Should You Buy?
After testing and researching all eight units, the best electric tankless water heaters for apartments come down to your apartment’s electrical service and your hot water demand. For most owners with a 150A-200A panel and a 1-2 bathroom apartment, the Stiebel Eltron Tempra 29 Plus is the safest long-term investment, and the Orbek 14kW is the smartest value pick. For renters and 100A panel apartments, the CAMPLUX TE06 and EcoSmart ECO 8 are the proven point-of-use options that install fast and run reliably.
Whatever you choose, check your electrical panel first, budget 500 to 1,000 dollars for professional installation on whole-apartment units, and size up 30% if you live in a cold climate. With the right pick, your apartment gets endless hot water, lower energy bills, and the kind of reliability that lets you stop thinking about your water heater entirely.