Affordable should mean low cost over the life of the heater, not just at checkout. The models here are reasonably priced to buy and save on running costs through condensing efficiency, self-modulating power or simpler installation. They suit small to mid-size homes, apartments and single bathrooms.
We compared efficiency, power draw, controls and installation needs using manufacturer specifications and owner feedback. For more features per dollar see the best value tankless water heater guide; our Editorial Policy explains our process. Gas units require professional installation.
Top 3 Best Affordable Tankless Water Heaters
ThermoMate CZ480NG Condensing Natural Gas Tankless Water Heater, 5.28 GPM
- Condensing
- UEF 0.86
- 5.28 GPM
Rinnai V53DeP 5.3 GPM Outdoor Propane Tankless Water Heater
- Outdoor
- 5.3 GPM
- Wi-Fi capable
WINTEMP WM15V 14.4kW 240V Wi-Fi Electric Tankless Water Heater
- 14.4kW
- One 60A circuit
- Wi-Fi
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Affordable Tankless Water Heaters Compared
| # | Product | Key Features | |
|---|---|---|---|
| 1 |  ThermoMate CZ480NG Condensing Natural Gas Tankless Water Heater, 5.28 GPM |
| Check Latest Price |
| 2 |  Rinnai V53DeP 5.3 GPM Outdoor Propane Tankless Water Heater |
| Check Latest Price |
| 3 |  WINTEMP WM15V 14.4kW 240V Wi-Fi Electric Tankless Water Heater |
| Check Latest Price |
| 4 |  Westinghouse 11kW 240V Wi-Fi Electric Tankless Water Heater |
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| 5 |  Stiebel Eltron DHX 10-2 Trend 9.6kW Electric Tankless Water Heater |
| Check Latest Price |
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1. ThermoMate CZ480NG Condensing Natural Gas Tankless Water Heater, 5.28 GPM
Lowest Running Cost Gas
- Condensing with dual heat exchanger, UEF 0.86
- 114,000 BTU, up to 5.28 GPM
- Up to 15% savings vs non-condensing (per maker)
- Installation kit included
- Needs condensate drain
- Natural gas only
- Fuel: natural gas
- Flow: up to 5.28 GPM
- Model: CZ480NG
ThermoMate’s CZ480NG brings condensing efficiency at an accessible price, so monthly gas use stays low.
It suits 1–2 bathroom homes.
Who the ThermoMate CZ480NG fits best
Small gas homes.
Who should skip the ThermoMate CZ480NG
Large families.
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2. Rinnai V53DeP 5.3 GPM Outdoor Propane Tankless Water Heater
Best Affordable Propane
- 5.3 GPM
- Compact outdoor install, no indoor vent
- Wi-Fi capable
- Enhanced scale detection
- Propane only
- Outdoor freeze planning needed
- Fuel: propane
- Flow: 5.3 GPM
- Model: V53DeP
Rinnai’s V53DeP is the brand’s compact outdoor option, avoiding indoor venting costs.
Scale detection warns before buildup hurts performance.
Who the Rinnai V53DeP fits best
Propane homes in mild climates.
Who should skip the Rinnai V53DeP
Indoor-only installs.
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3. WINTEMP WM15V 14.4kW 240V Wi-Fi Electric Tankless Water Heater
Best Affordable Electric
- 14.4kW, up to 3.5 GPM
- Needs one 60A breaker and 6 AWG wire
- Auto flow control for stable temperature
- Wi-Fi
- One shower at a time in colder areas
- Newer brand
- Power: 14.4kW, 240V
- Flow: up to 3.5 GPM
- Model: WM15V
WINTEMP keeps installation simple with a single circuit, which saves on electrician time.
Flow control keeps the temperature steady.
Who the WINTEMP WM15V fits best
Apartments and one-bath homes.
Who should skip the WINTEMP WM15V
Multi-bath homes.
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4. Westinghouse 11kW 240V Wi-Fi Electric Tankless Water Heater
Best Affordable Smart Pick
- 11kW, about 2.6 GPM
- Wi-Fi with Alexa and Google Home
- Temperature memory, 86–140°F
- 98% thermal efficiency (per maker)
- One point of use
- 60A breaker needed
- Power: 11kW, 240V
- Flow: up to 2.6 GPM
- Brand: Westinghouse
Westinghouse’s 11kW unit adds smart control at a modest cost.
Best for one bathroom or a kitchen.
Who the Westinghouse 11kW fits best
One bathroom.
Who should skip the Westinghouse 11kW
Whole-house use.
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5. Stiebel Eltron DHX 10-2 Trend 9.6kW Electric Tankless Water Heater
Best Affordable Point-of-Use
- 9.6kW self-modulating
- 3i flow and temperature sensors
- Anti-scald limits 109/122/131°F
- Works as a booster
- Single fixture
- Hardwired
- Power: 9.6kW, 240V
- Model: DHX 10-2 Trend
- Temp: 68–140°F
Stiebel’s DHX 10-2 heats only what one fixture needs, cutting waste at a distant sink or shower.
Its sensors keep temperature precise.
Who the Stiebel Eltron DHX 10-2 fits best
Distant fixtures.
Who should skip the Stiebel Eltron DHX 10-2
Whole-house use.
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Keeping Tankless Costs Down
- Condensing gas units use less fuel each month.
- Single-circuit electric units cost less to install.
- Point-of-use heaters avoid heating long pipe runs.
- Flush yearly to keep efficiency high.
Frequently Asked Questions
What is the most affordable tankless water heater to run?
The ThermoMate CZ480NG condensing gas unit.
Are electric tankless heaters low-cost to run?
They are efficient, but electricity rates vary by area.
Does outdoor install cost less?
It avoids indoor venting, which can save money.
Do smart features add cost?
A little, but they can help manage use.
Final Verdict: Best Affordable Tankless Water Heater
The ThermoMate CZ480NG has the lowest running cost among these picks. The Rinnai V53DeP is the best affordable propane unit, and the WINTEMP WM15V is the best affordable electric choice.
Lowest running cost: ThermoMate CZ480NG Condensing Natural Gas Tankless Water Heater, 5.28 GPM Check Latest Price
Propane: Rinnai V53DeP 5.3 GPM Outdoor Propane Tankless Water Heater Check Latest Price
Electric: WINTEMP WM15V 14.4kW 240V Wi-Fi Electric Tankless Water Heater Check Latest Price
Low cost to buy and to run is the real bargain.
Looking for something else? Browse all of our Water Heaters guides and the wider Heating & Cooling section.
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