Direct vent tankless water heaters provide on-demand hot water with compact designs and better energy efficiency. This guide highlights five top options suited for American homes, covering indoor and outdoor installations, various flow rates, and digital controls. Ideal buyers include large households needing high GPM, homes seeking WiFi or smart control, and installations with limited space. The following summaries help you compare features, safety, and suitability at a glance.
| Product | Best For | Approx. Flow | Key Benefit |
|---|---|---|---|
| MIZUDO Natural Gas Tankless Water Heater | Large families seeking smart control | 10.3 GPM | WiFi APP control with 199k BTU and strong safety features |
| NEW Rinnai RX199iN Condensing | Indoor/outdoor versatility and high demand | 11.1 GPM | Versa Vent, Smart Sense control, compact footprint |
| Westinghouse Smart Tankless 7.9 GPM | Mid-sized homes with WiFi control | 7.9 GPM | ±1°F temperature stability and app control |
| Westinghouse Smart Tankless 10.3 GPM | Large homes needing reliable flow | 10.3 GPM | High BTU rating and voice app control |
| ThermoMate CZ422NG | Budget-conscious homes or smaller needs | Up to 5 GPM | Smart flow control and multiple protections |
MIZUDO Natural Gas Tankless Water Heater
Best for large households that need robust hot water with smart management. The MIZUDO unit delivers up to 10.3 GPM with a 199,000 BTU rating and indoor installation. It supports 5–7 fixtures simultaneously, letting you run showers, laundry, and faucets without interruption. The connected app enables remote temperature control, scheduling, and energy-tracking, making it convenient for busy families. Safety features include 16+ protections, such as freeze protection down to -13°F and anti-dry firing. Caution: high capacity units may require professional venting and electrical considerations during installation.
NEW Rinnai RX199iN Condensing
Best for installation flexibility and high capacity in a compact form. The RX199iN can be installed indoors or outdoors using Versa Vent and supports propane or natural gas through a Smart Sense gas control system. It provides up to 11.1 GPM, useful for homes with multiple simultaneous hot-water needs. As a condensing model, it emphasizes energy efficiency. The model showcases a modern interface and quick flushing option, with WiFi control available through the Controlr module (note: module sold separately). Limitations include the need for proper venting and potential outdoor venting requirements in certain setups.
Westinghouse Smart Tankless 7.9 GPM
Best for mid-sized homes needing reliable whole-home hot water with smart features. This 7.9 GPM unit delivers up to 180,000 BTU and supports 3–5 fixtures simultaneously. It includes WiFi app control and an LED panel to monitor status. Temperature stability is kept within ±1°F by self-modulating technology, reducing cold bursts during showers. Caution: performance can vary with low inlet water temperatures or very high simultaneous demand.
Westinghouse Smart Tankless 10.3 GPM
Best for large homes needing high-flow hot water. This indoor natural gas model delivers up to 10.3 GPM and 199,000 BTU. It features smart WiFi app and voice control for convenient management, plus precise ±1°F temperature stability via self-modulating technology. It’s well-suited for homes with multiple baths or heavy appliance use. Limitation: larger units require adequate venting and electrical readiness for installation.
ThermoMate CZ422NG Natural Gas Tankless
Best for budget-minded buyers needing dependable on-demand hot water for modest homes. The CZ422NG provides up to 5 GPM with 113,000 BTU, suitable for two showers running simultaneously. It includes smart flow control and multiple protections (boil-dry, freeze, flame-out, etc.). The heat exchanger uses copper for better thermal conductivity and corrosion resistance, achieving high efficiency. Choose this if you have lower hot-water demand or limited installation space. Caution: capacity may be insufficient for larger households or simultaneous high-demand usage.
Buying Guide
- Size up your demand: higher GPM ratings suit larger homes; smaller units fit apartments or light-use scenarios.
- Ventilation and installation: direct vent and indoor/outdoor options affect venting requirements; professional assessment is advised.
- Fuel type and availability: natural gas vs. propane; confirm local utility compatibility and gas line capacity.
- Control features: WiFi, mobile apps, and voice control add convenience but may require additional accessories.
- Temperature stability: units with ±1°F stability reduce cold bursts; check inlet water temperature and climate.
- Safety and protections: look for freeze protection, flame sensing, anti-dry firing, and blockage monitoring.
- Maintenance: consider ease of flushing and cleaning; quick access to service ports can save time.
FAQ
- What is a direct vent water heater?
A direct vent heater draws outdoor air for combustion and vents exhaust directly outside, improving indoor air quality and installation flexibility. - Do these units support outdoor installation?
Some models, like certain Rinnai variants, offer indoor or outdoor installation with appropriate venting or vent caps. - Is WiFi control worth it?
It adds remote monitoring and scheduling but depends on your preferred level of remote management and home network reliability. - What should I consider for large households?
Look for higher GPM (or multiple fixtures) and robust safety protections to handle simultaneous hot-water demands. - Are condensing models more efficient?
Yes, condensing models typically achieve higher efficiency, which can reduce operating costs over time. - How important is temperature stability?
Stable temperatures prevent cold-water shocks, improving comfort during showers and other uses.