In these tankless water heater smart reviews we score four Wi-Fi models, two electric and two propane, on how useful their app and voice features are, how much hot water they deliver, how precisely they hold temperature and how demanding the install is.
All four were scored on the same criteria using manufacturer specifications and owner feedback. For our shortlist see the best tankless water heater smart guide; our Editorial Policy explains how we work.
Top 3 Smart Tankless Heaters From Our Reviews
APOLO WET-24K-G 24kW 240V Wi-Fi Electric Tankless Water Heater
- 24kW
- Voice control
- 5.55 GPM
MIZUDO 120,000 BTU 5.1 GPM Wi-Fi Propane Tankless (Indoor/Outdoor)
- Indoor/outdoor
- Wi-Fi
- Anti-freeze
ET011C 11kW 240V Smart Electric Tankless Water Heater with Scale Inhibitor
- Scale inhibitor
- 11kW
- Temp memory
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How We Scored Smart Tankless Heaters
| Criterion | Weight | What we look at |
|---|---|---|
| Smart features | 30% | App, voice, presets, alerts |
| Flow | 25% | GPM for the home |
| Temperature control | 20% | Stability, modulation |
| Install | 15% | Breakers, venting |
| Maintenance | 10% | Scale protection, diagnostics |
| Water heater | Score | Best for |
|---|---|---|
| APOLO 24kW Wi-Fi | 8.8/10 | Electric whole-home |
| MIZUDO 5.1 GPM LP | 8.5/10 | Flexible propane installs |
| Westinghouse 5.1 GPM LP | 8.3/10 | Indoor propane homes |
| ET011C 11kW | 8.0/10 | Apartments |
Smart Tankless Heaters Compared
| # | Product | Key Features | |
|---|---|---|---|
| 1 |  APOLO WET-24K-G 24kW 240V Wi-Fi Electric Tankless Water Heater |
| Check Latest Price |
| 2 |  MIZUDO 120,000 BTU 5.1 GPM Wi-Fi Propane Tankless (Indoor/Outdoor) |
| Check Latest Price |
| 3 |  Westinghouse AMZ-HW120A1G-LP 5.1 GPM Wi-Fi Propane Tankless (Indoor) |
| Check Latest Price |
| 4 |  ET011C 11kW 240V Smart Electric Tankless Water Heater with Scale Inhibitor |
| Check Latest Price |
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1. APOLO WET-24K-G 24kW 240V Wi-Fi Electric Tankless Water Heater
Highest Overall Score: 8.8/10
- 24kW, up to 5.55 GPM
- Wi-Fi with Alexa and Google Home
- 86–140°F range
- ETL certified
- About 100A draw, three 40A breakers
- Starts at about 0.79 GPM
- Power: 24kW, 240V
- Model: WET-24K-G
- Flow: up to 5.55 GPM
The APOLO 24kW scored highest for whole-home electric flow plus voice control.
Confirm panel capacity before buying.
Who the APOLO 24kW Wi-Fi fits best
Electric homes with large service.
Who should skip the APOLO 24kW Wi-Fi
Small panels.
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2. MIZUDO 120,000 BTU 5.1 GPM Wi-Fi Propane Tankless (Indoor/Outdoor)
Best Propane Flexibility: 8.5/10
- 120,000 BTU, up to 5.1 GPM
- Indoor or outdoor convertible install
- Wi-Fi app control
- Anti-freeze protection, CSA certified
- Newer brand
- 2–4 fixtures
- Fuel: propane
- Flow: up to 5.1 GPM
- Brand: MIZUDO
MIZUDO’s convertible design lets you choose indoor or outdoor install as your home allows.
The app adds remote temperature control.
Who the MIZUDO 5.1 GPM LP fits best
Propane homes.
Who should skip the MIZUDO 5.1 GPM LP
Natural gas homes.
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3. Westinghouse AMZ-HW120A1G-LP 5.1 GPM Wi-Fi Propane Tankless (Indoor)
Solid Smart Propane: 8.3/10
- 120,000 BTU, up to 5.1 GPM
- Wi-Fi app control
- ±1°F temperature control
- CSA certified
- Indoor venting needed
- Propane only
- Fuel: propane
- Flow: up to 5.1 GPM
- Model: AMZ-HW120A1G-LP
Westinghouse’s propane unit gives steady temperature with app control for 1–2 bath homes.
Install and vent it by a pro.
Who the Westinghouse 5.1 GPM LP fits best
Indoor propane installs.
Who should skip the Westinghouse 5.1 GPM LP
Large homes.
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4. ET011C 11kW 240V Smart Electric Tankless Water Heater with Scale Inhibitor
Best Low Maintenance: 8.0/10
- Wi-Fi app and Alexa voice control (per listing)
- Included inlet scale inhibitor with replaceable cartridge
- 11kW self-modulating
- Temperature memory and LED display
- Low-flow and overheat protection
- 1–2 fixtures
- Little-known brand
- Power: 11kW, 240V
- Model: ET011C
- Install: hardwired
This 11kW unit stands out for its scale inhibitor, which protects the element in hard water areas.
It suits apartments.
Who the ET011C 11kW fits best
Hard water apartments.
Who should skip the ET011C 11kW
Whole-house use.
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Smart Setup Tips
- Check 2.4GHz Wi-Fi near the heater.
- Set temperature locks to prevent scalding.
- Keep firmware and apps updated.
- Use alerts to schedule flushing.
Frequently Asked Questions
Which smart tankless heater scored highest?
The APOLO 24kW Wi-Fi scored 8.8/10.
Do I need Wi-Fi for it to work?
No; Wi-Fi only adds remote features.
Can I control a gas tankless heater from my phone?
Yes, with Wi-Fi models like MIZUDO and Westinghouse.
Are smart features worth it?
They help with remote control, presets and alerts.
Final Verdict: Tankless Water Heater Smart Reviews
The APOLO 24kW Wi-Fi is the best smart tankless heater we scored. The MIZUDO 5.1 GPM offers the best propane flexibility, and the ET011C 11kW is the lowest maintenance.
Overall: APOLO WET-24K-G 24kW 240V Wi-Fi Electric Tankless Water Heater Check Latest Price
Propane: MIZUDO 120,000 BTU 5.1 GPM Wi-Fi Propane Tankless (Indoor/Outdoor) Check Latest Price
Low maintenance: ET011C 11kW 240V Smart Electric Tankless Water Heater with Scale Inhibitor Check Latest Price
Smart control is a nice upgrade when the basics are right.
Looking for something else? Browse all of our Water Heaters guides and the wider Heating & Cooling section.
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