Best Tankless Water Heaters for Residential Use
Choosing a tankless water heater for a home can reduce energy use, save space, and provide steady hot water on demand. This guide highlights five top options across electric and gas models, focusing on reliability, capacity, and smart features that matter for American households. Each product is evaluated by flow rate, energy efficiency, installation considerations, and user-friendly controls to help you select a model that fits your home’s hot water needs.
Product Summary
| Product | Brand | Type | Approx. Flow (GPM) | Notes |
|---|---|---|---|---|
| Rheem 18kW 240V Tankless Electric Water Heater, Gray | Rheem | Electric | Up to 4.4 | Self-modulating, LED display, serviceable elements |
| Rheem RTEX-13 Residential Tankless Water Heater, Gray | Rheem | Electric | Not specified here | Self-modulating, easy installation adapters |
| Westinghouse APOLO-14kW 240V Smart WiFi | Westinghouse | Electric | Up to 3.38 | Smart Wi-Fi, Alexa/Google Home, compact |
| WINTEMP 27kW 240V | WINTEMP | Electric | Up to 6.3 | LED, WiFi, 99% energy savings potential |
| ThermoMate CZ422NG Natural Gas Tankless | ThermoMate | Gas | Up to 5 | Multi-point heating, compact, high efficiency |
All five options balance compact design with reliable output for typical American households—ranging from one bathroom to whole-house setups. Electric models suit homes with adequate electrical service, while gas units deliver higher steady flow. Consider your home’s existing wiring, gas lines, and climate when selecting a model.
Rheem 18kW 240V Tankless Electric Water Heater, Gray
The Rheem 18kW electric unit uses self-modulating power to match hot water demand, reducing energy use when demand is low. It features an external digital thermostat with LED readout for precise temperature control, accurate within +/-1 degree. Copper immersion heating elements offer durability, and the unit is field serviceable. Typical maximum flow reaches about 4.4 GPM, suitable for smaller homes or point-of-use applications. Installation requires proper 240V electrical service and appropriate circuit protection. This model emphasizes quick temperature stability and compact footprint for tight spaces.
Rheem RTEX-13 Residential Tankless Water Heater, Gray
The Rheem RTEX-13 offers a compact electric tankless solution with self-modulating power and an external digital thermostat displaying in +/-1 degree increments. It uses copper immersion heating elements and is designed for straightforward installation, including side water connections and 1/2 NPT adapters. The unit supports variable water flow and temperature control suitable for smaller households or apartments. Its modular design makes servicing convenient, helping maintain efficient operation over time.
Rheem RTGH Series 8.4 GPM Gas Tankless (Indoor)
The gas-fueled Rheem RTGH84DVLN offers a higher hot-water output with a flow range from 0.4 to 8.4 GPM and multiple temperature settings—from 100 to 140°F (default 120°F). It includes electric ignition for reliable starts and is designed for indoor installation. Gas models can handle larger households or multiple simultaneous uses more effectively than electric equivalents. Consider venting, gas line sizing, and venting requirements in installation planning.
Westinghouse APOLO-14kW 240V Smart WiFi
The Westinghouse APOLO-14kW offers smart Wi-Fi control compatible with Alexa and Google Home, enabling remote temperature management and monitoring. It delivers up to about 3.38 GPM, suitable for a single bathroom or small household when used strategically. The unit supports real-time status display and allows temperature adjustments in small increments, with a bottom 1/2″ NPT connections. Its compact design suits tight spaces and modern retrofit projects that want smart-home integration.
WINTEMP 27kW 240V Electric Tankless
The WINTEMP 27kW electric model is designed for whole-house use, with a maximum of 6.3 GPM. It requires substantial electrical service (up to 113A), multiple 40A DP breakers, and 8 AWG wiring with ground. The unit provides a stable output with LED temperature display and Wi-Fi control, enabling remote adjustments and monitoring. This model is best suited for homes with higher hot-water demand and adequate electrical capacity, offering energy efficiency through self-regulating power input based on flow and temperature.
WINTEMP 36kW Tankless Electric Water Heater
The WINTEMP 36kW model is designed for larger homes with higher-demand scenarios. It requires four 40A double-pole breakers and robust wiring (8 AWG), with a recommended 300A service. It can deliver up to 8.7 GPM and includes Wi-Fi control for remote management. This unit emphasizes high throughput and consistent temperature, making it suitable for households with multiple showers running simultaneously or high-flow appliances.
Buying Guide
When selecting a tankless water heater for a residence, consider these key factors:
- Hot-water demand: Estimate peak GPM by calculating simultaneous uses (shower, faucet, dishwasher). Electric units generally offer lower GPM than gas models; plan for future needs.
- Electrical/Gas capacity: Electric heaters require adequate circuit capacity and panel space; large 27kW+ models may require upgrades. Gas units need venting and proper line sizing.
- Energy efficiency: Self-modulating technology helps save energy by adjusting heat output to demand. Look for high energy factors and compatible insulation.
- Control interface: LED displays, digital thermostats, and smart home integration provide precise control and monitoring. Wi-Fi capabilities can aid diagnostics and schedule-based use.
- Installation considerations: Space, venting (gas models), water connections, and local codes affect selection. Professional installation is recommended for gas and high-wattage electric units.
- Maintenance: Field-serviceable elements and accessible heat exchangers simplify upkeep. Consider availability of replacement parts in your region.
- Space savings: Tankless units significantly reduce footprint compared with tanks. Evaluate mounting options and access for service.
Choosing between electric and gas depends on existing infrastructure, local energy costs, and climate. Electric models are generally easier to install in a retrofit scenario with sufficient panel capacity, while gas units deliver higher continuous flow for larger households. Smart features and modular heating elements can enhance longevity and ease maintenance. Always verify electrical or gas requirements with a licensed professional before purchasing.