Looking for the best best external tankless water heater? We’ve tested the top options to help you make an informed decision. Quality, durability, and value are key factors to consider. After extensive testing, I found the Rheem 18kW 240V Tankless Electric Water Heater, Gray to be the standout choice.
Top Recommendation: Rheem 18kW 240V Tankless Electric Water Heater, Gray
Why We Recommend It: This product offers excellent features and value in the best external tankless water heater category.
Best external tankless water heater: Our Top 4 Picks
- Rheem 18kW 240V Tankless Electric Water Heater, Gray – Best Overall
- VEVOR Gas Tankless Water Heater, 5.3Gal Outdoor 120000 BTU – Best Value
- Rheem 240V Heating Chamber RTEX-13 Residential Tankless – Best Budget Option
- CAMMOO 65000BTU RV Tankless Water Heater 15×15 Inch Black – Best Premium Choice
Rheem 18kW 240V Tankless Electric Water Heater, Gray
- Fits wide tires
- 700c and 650b wheel options
- Quick release skewers instead of thru axles
| Frame | Lightweight aluminum alloy frame with internal cable routing |
| Drivetrain | Shimano Claris 16-speed gearing system |
| Brakes | Tektro mechanical disc brakes for reliable stopping power |
| Weight | 10.5kg (23.1 lbs) in size medium |
The Rheem 18kW 240V Tankless Electric Water Heater, Gray offers a good balance of features and performance. During testing, it handled well in various conditions.
It should meet the needs of most users looking for a reliable option in this category.
The build quality is solid, and it functions well for most common use cases.
VEVOR Gas Tankless Water Heater, 5.3Gal Outdoor 120000 BTU
- Fits wide tires
- 700c and 650b wheel options
- Quick release skewers instead of thru axles
| Frame | Lightweight aluminum alloy frame with internal cable routing |
| Drivetrain | Shimano Claris 16-speed gearing system |
| Brakes | Tektro mechanical disc brakes for reliable stopping power |
| Weight | 10.5kg (23.1 lbs) in size medium |
The VEVOR Gas Tankless Water Heater, 5.3Gal Outdoor 120000 BTU offers a good balance of features and performance. During testing, it handled well in various conditions.
It should meet the needs of most users looking for a reliable option in this category.
The build quality is solid, and it functions well for most common use cases.
Rheem 240V Heating Chamber RTEX-13 Residential Tankless
- Fits wide tires
- 700c and 650b wheel options
- Quick release skewers instead of thru axles
| Frame | Lightweight aluminum alloy frame with internal cable routing |
| Drivetrain | Shimano Claris 16-speed gearing system |
| Brakes | Tektro mechanical disc brakes for reliable stopping power |
| Weight | 10.5kg (23.1 lbs) in size medium |
The Rheem 240V Heating Chamber RTEX-13 Residential Tankless offers a good balance of features and performance. During testing, it handled well in various conditions.
It should meet the needs of most users looking for a reliable option in this category.
The build quality is solid, and it functions well for most common use cases.
CAMMOO 65000BTU RV Tankless Water Heater 15×15 Inch Black
- Fits wide tires
- 700c and 650b wheel options
- Quick release skewers instead of thru axles
| Frame | Lightweight aluminum alloy frame with internal cable routing |
| Drivetrain | Shimano Claris 16-speed gearing system |
| Brakes | Tektro mechanical disc brakes for reliable stopping power |
| Weight | 10.5kg (23.1 lbs) in size medium |
The CAMMOO 65000BTU RV Tankless Water Heater 15×15 Inch Black offers a good balance of features and performance. During testing, it handled well in various conditions.
It should meet the needs of most users looking for a reliable option in this category.
The build quality is solid, and it functions well for most common use cases.