A value tankless water heater gives you the features that matter, such as steady temperature, a solid warranty and serviceable parts, without paying for extras you will not use. These five deliver the most per dollar for their size class, from a whole-house propane unit to compact electric models for apartments and single bathrooms.
We compared features, warranty, flow and installation needs using manufacturer specifications and owner feedback. For the lowest purchase cost see the best budget tankless water heater guide; our Editorial Policy explains our process. Gas units require professional installation.
Top 3 Best Value Tankless Water Heaters
Rinnai RE140iP Non-Condensing Indoor Propane Tankless Water Heater
- 5.3 GPM
- 15-yr HX
- Propane
EcoSmart ECOS 12 12kW 240V Electric Tankless Water Heater
- 12kW
- 50A
- ±1°F
ThermoMate ET110HCUS 11kW 240V Electric Tankless Water Heater
- 11kW
- No-leak design
- 3 faucets
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Best Value Tankless Water Heaters Compared
| # | Product | Key Features | |
|---|---|---|---|
| 1 |  Rinnai RE140iP Non-Condensing Indoor Propane Tankless Water Heater |
| Check Latest Price |
| 2 |  EcoSmart ECOS 12 12kW 240V Electric Tankless Water Heater |
| Check Latest Price |
| 3 |  ThermoMate ET110HCUS 11kW 240V Electric Tankless Water Heater |
| Check Latest Price |
| 4 |  Rheem RTEX-08 8kW 240V Electric Tankless Water Heater |
| Check Latest Price |
| 5 |  QERPRE 100,000 BTU Natural Gas Tankless Water Heater, 4.3 GPM |
| Check Latest Price |
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1. Rinnai RE140iP Non-Condensing Indoor Propane Tankless Water Heater
Best Value Overall
- Up to 5.3 GPM, about 5 fixtures
- 15-year heat exchanger, 5-year labor, 1-year parts guarantee
- LED screen with service reminders and error codes
- Compact indoor unit
- Propane version only
- Wi-Fi needs the Control-R module
- Fuel: propane
- Flow: up to 5.3 GPM
- Model: RE140iP
The Rinnai RE140iP brings a major brand’s warranty and service network at an entry price for that brand.
It suits 1–2 bathroom propane homes.
Who the Rinnai RE140iP fits best
Small propane homes.
Who should skip the Rinnai RE140iP
Large households.
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2. EcoSmart ECOS 12 12kW 240V Electric Tankless Water Heater
Best Value Electric
- 12kW, up to 2.9 GPM
- Single 50A circuit
- Holds temperature within 1°
- Compact, wall or point-of-use mounting
- One shower at a time in most climates
- No app
- Power: 12kW, 240V
- Flow: up to 2.9 GPM
- Model: ECOS 12
EcoSmart’s ECOS 12 is easy to wire on one circuit and gives steady temperature.
It suits apartments or a bathroom addition.
Who the EcoSmart ECOS 12 fits best
Apartments and additions.
Who should skip the EcoSmart ECOS 12
Multi-bath homes.
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3. ThermoMate ET110HCUS 11kW 240V Electric Tankless Water Heater
Best Value Small Home
- 11kW supports up to 3 faucets
- Cast aluminum chamber keeps element away from water
- Self-modulating
- Needs one 50A breaker
- Max outlet about 131°F
- About 2.2 GPM at 35°F rise
- Power: 11kW, 240V
- Model: ET110HCUS
- Flow: up to 2.6 GPM
ThermoMate’s dry-element design limits scale on the element, which can cut maintenance.
It is a good fit for a small home or ADU.
Who the ThermoMate ET110 fits best
ADUs and small homes.
Who should skip the ThermoMate ET110
Showers in cold climates.
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4. Rheem RTEX-08 8kW 240V Electric Tankless Water Heater
Best Value Point-of-Use
- 8kW, about 1.95 GPM
- One 40A breaker, 100A panel recommended
- Digital control 80–140°F in 1° steps
- Serviceable brand
- One fixture
- Low flow
- Power: 8kW, 240V
- Flow: up to 1.95 GPM
- Model: RTEX-08
Rheem’s RTEX-08 is a low-demand unit for a sink or small shower far from the main heater.
It has the lightest electrical requirements here.
Who the Rheem RTEX-08 fits best
Remote sinks.
Who should skip the Rheem RTEX-08
Whole-house needs.
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5. QERPRE 100,000 BTU Natural Gas Tankless Water Heater, 4.3 GPM
Best Value Gas
- 100,000 BTU, up to 4.3 GPM
- Self-modulating, ±1°F
- Supports 2–3 water points
- Indoor natural gas install
- Newer brand
- Venting must be planned
- Fuel: natural gas
- Flow: up to 4.3 GPM
- Burner: 100,000 BTU
QERPRE gives a lot of features for the money, including self-modulation.
Get it installed and vented by a pro.
Who the QERPRE 4.3 GPM fits best
Small gas homes.
Who should skip the QERPRE 4.3 GPM
Large homes.
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How to Judge Value in a Tankless Water Heater
- Warranty: heat exchanger coverage matters most.
- Install cost: fewer breakers or simpler venting saves money.
- Right size: do not pay for flow you will never use.
- Service network: major brands are easier to repair.
Frequently Asked Questions
What is the best value tankless water heater?
The Rinnai RE140iP for its warranty and service network.
Is a lower-cost gas unit good value?
It can be if installed correctly and sized well.
Which electric unit is easiest to install?
The Rheem RTEX-08 needs one 40A breaker.
How do I size for value?
Match GPM to fixtures used at once.
Final Verdict: Best Value Tankless Water Heater
The Rinnai RE140iP is the best value tankless water heater overall. The EcoSmart ECOS 12 is the best value electric unit, and the ThermoMate ET110 is best for small homes.
Value overall: Rinnai RE140iP Non-Condensing Indoor Propane Tankless Water Heater Check Latest Price
Value electric: EcoSmart ECOS 12 12kW 240V Electric Tankless Water Heater Check Latest Price
Small home: ThermoMate ET110HCUS 11kW 240V Electric Tankless Water Heater Check Latest Price
Pay for what your household actually uses.
Looking for something else? Browse all of our Water Heaters guides and the wider Heating & Cooling section.
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