Choosing a condensing gas water heater can dramatically cut energy use while delivering reliable hot water for households of all sizes. This guide highlights five top options, spanning condensing and non-condensing designs, indoor and outdoor installations, and varied flow rates to meet busy homes. Each model prioritizes efficiency, safety, and user-friendly controls to help you compare features quickly and make an informed purchase.
| Product | Type | Max GPM | Key Benefit |
|---|---|---|---|
| ThermoMate CZ480NG | Condensing Tankless | 5.28 GPM | Dual heat exchangers and 0.86 UEF for efficiency |
| Rinnai RX199iN | Condensing Tankless | Up to 11.1 GPM | Indoor/outdoor versatility with Smart Sense control |
| Rheem RTG-70DVLN-3 | Non-condensing Tankless | 7.0 GPM | Durable indoor unit with strong BTUs for peak demand |
| Rinnai RX130iN | Condensing Tankless | Up to 7.1 GPM | Compact design with Versa Vent and WiFi-ready potential |
| Westinghouse APOLO | Non-condensing Tankless | Up to 7.9 GPM | Smart temp control and app-based adjustments |
ThermoMate CZ480NG Condensing Tankless Water Heater
The ThermoMate CZ480NG is a condensing tankless unit designed for indoor residential use. It features a 0.86 UEF efficiency and a dual heat exchanger system that combines a corrosion-resistant stainless steel condensing exchanger with an oxygen-free copper exchanger. This setup captures and reuses waste heat to maximize energy recovery, helping reduce ongoing energy costs. With 5.28 GPM flow, it can serve two showers simultaneously at comfortable temperatures, using a precise flow sensor and fast-reacting control that maintains water within about ±1°F. Several safety protections guard against common gas-water failures, including boil-dry and freeze protections.
Key features include dual heat exchangers, 114,000 BTU input, and robust protection systems. This model aims to balance compact indoor footprint with reliable hot water for mid-sized households, reducing hot-water delays and improving comfort during peak usage times.
Rinnai RX199iN Condensing Smart Sense Water Heater
The Rinnai RX199iN is a high-capacity condensing tankless model designed for indoor or outdoor installation using Versa Vent. It supports natural gas or propane with a Smart Sense gas control, and it can deliver up to 11.1 GPM, suitable for larger households or homes with multiple simultaneous hot-water demands. The unit emphasizes ease of use via an intuitive interface and Quick Flush functionality for maintenance. Notably, its efficiency rating is among the top in this category, with a UEF approaching 0.98, supporting low operating costs. WiFi control is available through an optional ControlR module.
With compact dimensions despite its performance, RX199iN provides flexible installation and strong resilience for year-round hot water under varying demand. The system’s protective features and advanced venting options help ensure safe operation and long service life, making it a solid choice for busy homes needing reliable hot water delivery.
Rheem RTG-70DVLN-3 High Efficiency Non-Condensing Indoor
The Rheem RTG-70DVLN-3 is a high-efficiency non-condensing indoor tankless water heater rated at 7.0 GPM and 160,000 BTUs. It is designed for compact indoor installation with a durable metal cabinet and straightforward wall mounting for qualified installers. This model emphasizes reliability and solid performance during peak demand, ensuring continuous hot water supply for households with multiple hot-water needs. While non-condensing, its efficiency remains strong for smaller homes or retrofit projects where venting and space constraints are a priority.
Designed for indoor use, the RTG-70DVLN-3 provides a robust option for homeowners seeking dependable hot water without the complexities of condensing systems. Its straightforward operation and installation can make it a practical choice for modernizing older homes or upgrading away from storage tanks.
Rinnai RX130iN Condensing Smart Sense Indoor/Outdoor
The RX130iN from Rinnai is a compact condensing tankless heater designed for versatile installation, indoors or outdoors, thanks to Versa Vent. It supports both propane and natural gas and delivers up to 7.1 GPM, suitable for small-to-midsize homes. The unit includes a Quick Flush feature for easier maintenance and offers a high efficiency factor (UEF around .97). An optional ControlR module enables WiFi-based monitoring and control, giving users flexibility in managing temperature and performance. This model balances footprint, efficiency, and user-friendly controls for homes with space constraints or outdoor venting needs.
With robust safety features and a space-saving profile, the RX130iN is a practical pick for installers prioritizing versatility and energy efficiency in a single compact unit. Its reliable performance under varied conditions makes it a strong contender for modern homes seeking instant hot water with efficient operation.
Westinghouse APOLO Natural Gas Tankless Water Heater
The Westinghouse APOLO is a non-condensing, indoor tankless water heater with a maximum output around 7.9 GPM and 180,000 BTU. It emphasizes on-demand efficiency with an LED display for temperature, status, and error codes. The system supports smart temperature adjustments via a companion smartphone app and provides stable water temperatures within a tight tolerance, helping reduce fluctuations during rapid demand changes. Its design is suitable for whole-home use, delivering reliable hot water without the complexity of condensing technology.
APOLO focuses on practical, user-friendly operation with straightforward maintenance and monitoring features. This makes it a solid option for homes seeking a non-condensing, cost-effective tankless solution that still maintains consistent performance across multiple fixtures.
Buying Guide: Key Considerations When Choosing A Condensing Gas Water Heater
- Efficiency and fuel type: Condensing models generally offer higher efficiency (UEF) by reclaiming heat from flue gases. Decide between natural gas or propane based on availability and installation constraints in your home.
- Flow rate and simultaneous demand: Estimate peak GPM needs for showers, sinks, and laundry. Condensing units often provide higher efficiency at larger capacities, while non-condensing options may pair well with modest hot-water loads.
- Indoor vs outdoor installation: Condensing units frequently require venting. Consider space, ventilation, and local code requirements. Some models offer indoor/outdoor versatility with flexible venting options.
- Ventilation and installation: Check the venting compatibility (direct vent, VERSA vent, etc.) and whether the unit supports easy maintenance features like Quick Flush. A qualified installer is recommended for safe setup.
- Controls and connectivity: Many units offer digital displays, temperature controls, and optional WiFi/ControlR modules for remote monitoring. Evaluate whether smart features align with your lifestyle.
- Warranty and service: Look for unit warranties and available local service coverage. Condensing units may have more components that require professional servicing.
- Durability and materials: Dual heat exchangers, stainless steel components, and corrosion-resistant parts improve long-term reliability in varied water conditions.
- Operating costs: While prices vary, condensing models typically reduce energy usage. Consider long-term savings versus upfront installation costs.