Tankless Electric, Installed
Tankless Electric Water Heater Installation Cost
A tankless electric water heater installed costs $1,000 to $2,500 for most configurations in 2026. The honest qualifier nobody puts in the headline: many whole-house installs require a panel upgrade adding $1,800 to $4,500. Below, the realistic cost by configuration (point-of-use through whole-house large), the panel-load math that determines whether your home can support the unit, and where tankless electric does and does not make sense.
Quick answer: $450 to $1,000 for a point-of-use under-sink unit. $1,000 to $2,500 for a whole-house unit when the panel can support the load. $3,000 to $7,000 fully loaded if a 200A panel upgrade is required.
Cost Table
Tankless Electric Cost by Configuration
Flow rate falls as the temperature rise required (incoming water temperature subtracted from desired output) increases. The smaller units listed are honest about their limits: a 4 kW under-sink unit cannot serve a shower with 50F incoming water.
| Type | Flow Rate | Unit Price | Install | Best For |
|---|---|---|---|---|
| Point-of-use under-sink (4 to 6 kW) | 0.5 to 1.5 GPM at 70F rise | $300 to $700 | $150 to $300 | Single sink, half-bath, ADU prep sink |
| Point-of-use single-shower (8 to 13 kW) | 1.5 to 2.5 GPM at 70F rise | $500 to $900 | $200 to $500 | One bathroom in remote location, garage shower |
| Whole-house small (18 to 24 kW) | 3 to 4 GPM at 60F rise | $600 to $1,000 | $400 to $1,000 | Mild climate, 1 to 2 bath, 1 to 2 people |
| Whole-house large (27 to 36 kW) | 4 to 6 GPM at 50F rise | $900 to $1,500 | $500 to $1,500 | Mild climate, 2 to 3 bath, family of 3 to 4 |
Major manufacturers in this category: Rinnai, Stiebel Eltron, EcoSmart, Rheem, Bosch. Unit pricing reflects retail at Home Depot, Lowe's, and direct-to-consumer channels. Install pricing assumes existing circuit capacity is adequate.
The Detail Most Quotes Skip
You Probably Need a Panel Upgrade
A 27 kW whole-house tankless electric draws roughly 113 amps at 240V (27,000 watts divided by 240V). A 36 kW unit draws 150 amps. Per the National Electrical Code continuous-load rule, the supply must be sized to 125 percent of that, so a 36 kW unit needs 187.5A of available panel capacity dedicated to the heater alone. In a 100A-service home, this is impossible. In a 150A-service home, it leaves no margin for the rest of the house. Only 200A-service homes have honest headroom for a whole-house tankless electric, and even then only if other major loads (HVAC compressor, EV charger, electric range) do not all fire simultaneously.
Panel age is the proxy for service size. Homes built before 1960 typically have 60A or 100A service. Homes built 1960 to 1990 commonly have 100A or 150A. Homes built 1990 to 2010 typically have 150A or 200A. Newer construction is mostly 200A. If you do not know your service size, look at the main breaker in the panel; the number stamped on it (60, 100, 150, 200) is your service size.
A 100A to 200A panel upgrade costs $1,800 to $4,500. The cost components are the new panel ($300 to $800), the new breakers ($300 to $600 in aggregate), the mast and meter base coordination with the utility ($300 to $1,000 depending on whether the meter location must move), permit and inspection ($100 to $400), and labour ($800 to $1,800 for an 8 to 12 hour job). The utility typically does not charge for the new service drop on a residential panel upgrade unless the drop is undersized or the meter location must change, in which case add $500 to $2,000.
The honest sequence: get a load calculation from a licensed electrician before you order the tankless electric unit. The calculation factors all existing loads at the NEC-required diversity factors and tells you exactly how many amps of headroom you have. If the headroom is less than 125 percent of the heater nameplate amperage, you need either a panel upgrade or a smaller heater. There is no third option.
Sizing Math
The Flow-Rate vs Temperature-Rise Math
Tankless heater flow-rate ratings depend on the temperature rise required. A unit rated for 6 GPM at 30F rise delivers only 3 GPM at 60F rise. The water in the supply main has to be heated from whatever temperature it enters the home at to the desired output temperature, typically 105 to 110F at the fixture. Incoming water temperature varies by region: 70 to 75F in southern Florida and coastal Texas, 50 to 55F in the Midwest, 40 to 45F in northern New England and the Pacific Northwest in winter.
Apply the math to a single shower. A typical low-flow showerhead uses 1.8 GPM at 105F. In Miami where incoming water is 75F, the required rise is 30F and a 12 to 15 kW point-of-use unit handles the load. In Minneapolis where incoming water is 45F, the required rise is 60F and a 24 kW unit is needed for the same single-shower performance. For two simultaneous showers in Minneapolis, a 36 kW whole-house unit is the minimum, with a panel upgrade almost certainly required.
The DOE sizing guidance recommends sizing tankless units to the simultaneous peak hot-water demand, not the average. List the fixtures that might run at the same time (master shower 2.0 GPM, kitchen sink 1.5 GPM, dishwasher 1.0 GPM = 4.5 GPM combined) and confirm the unit can deliver that flow at the required temperature rise for your climate. Manufacturers publish flow-rate-by-rise tables for every model; they live in the spec sheet, not the marketing materials.
Decision Guide
When Tankless Electric Is the Right Answer
Point-of-use, remote fixture
A garage utility sink, ADU half-bath, basement workshop sink, far-end-of-house powder room. Any fixture more than 30 to 40 feet from the main water heater wastes 1 to 2 gallons every time you run the tap waiting for hot water. A point-of-use tankless under the sink eliminates that waste at $450 to $1,000 installed.
Mild climate, modern panel
Whole-house tankless electric is realistic in Sun Belt homes with 200A service. Incoming water above 65F all year keeps required kW manageable. Texas, Florida, southern California, Arizona homes built post-2000 are the cleanest fit.
Tight closet, no venting access
Condos and apartments where the tank water heater closet is too small for a tankless gas vent run, but a 27 kW wall-mounted tankless electric fits. The HOA may explicitly prohibit gas, leaving electric as the only option.
Backup or supplementary use
A point-of-use unit can serve as backup if the main heater fails, or as supplementary boost for a single high-demand fixture (a soaking tub or steam shower). Cost is low, install is low-friction, and the redundancy buys peace of mind.
FAQ
Tankless Electric Installation Questions
How much does a tankless electric water heater cost installed?
A tankless electric water heater installed costs $1,000 to $2,500 in 2026. Point-of-use units (single sink or shower) start at $300 to $700 unit plus $200 to $500 install. Whole-house tankless electric units cost $700 to $1,500 unit plus $500 to $1,500 install, often including a panel upgrade. The honest range many homeowners do not see quoted: $2,500 to $4,500 if a panel upgrade is required.
Will a whole-house tankless electric work in my home?
It depends on the panel and the climate. A whole-house tankless electric draws 80 to 150 amps at peak (multiple 40A circuits). Most homes built before 1990 have 100A or 150A service and cannot support that load alongside HVAC and EV charging. Cold-climate homes face an additional problem: incoming groundwater at 40 degrees Fahrenheit needs more energy to reach 105 degrees output than 65-degree groundwater. Whole-house tankless electric works best in 200A-service homes in mild climates.
How much does a panel upgrade cost for a tankless electric heater?
A 100A to 200A residential panel upgrade costs $1,800 to $4,500 depending on the utility and the existing meter location. The cost includes the new panel, breakers, mast and meter coordination with the utility, and inspection. If the existing service drop is undersized, the utility may charge an additional $500 to $2,000 for the new drop. Always price the panel upgrade before signing for a tankless electric install.
Is tankless electric cheaper than tankless gas?
Cheaper to install (no venting, no gas-line upsize), more expensive to operate. A whole-house tankless electric installed (without panel upgrade) costs $1,500 to $2,500 versus $2,500 to $5,000 for tankless gas. Annual operating cost on tankless electric runs $350 to $500 versus $200 to $300 for tankless gas in the same household. Over a 15 to 20 year lifespan, tankless gas wins on total cost in most regions where natural gas is available.
What is the cheapest tankless electric setup?
A point-of-use unit serving one or two fixtures. A 4 to 6 kW point-of-use tankless under a kitchen sink or for a single bathroom sink costs $300 to $500 unit plus $150 to $300 install on the existing 30A or 40A circuit. This is the lowest-friction tankless configuration and is appropriate where you need on-demand hot water for a remote fixture without pulling a hot line from the main heater.
Compare
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Permits
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