In today’s homes, an efficient gas hot water heater means reliable hot water with lower energy use. This guide highlights five efficient models ideal for medium to larger homes with multiple simultaneous hot-water needs. The list targets buyers who want strong flow at the point of use, indoor or outdoor installation options, and smart controls. Each product section explains who benefits most and why it was selected, plus a practical caution to consider during installation and use. A quick buying guide follows to help you compare features, efficiency, and suitability for your home.
| Product | GPM | BTU | Best For |
|---|---|---|---|
| Rheem RTG-70DVLN-3 | 7.0 | 160,000 | 2–3 bathroom homes with multiple needs |
| Rheem RTG-84XLN-3 | 8.4 | 180,000 | Outdoor installation with high simultaneous usage |
| APUS 190,000 BTU | 8.1 | 190,000 | Whole-house, WiFi control, strong flow |
| Rheem Condensing Indoor 9 GPM | ≤9 | 180,000 | High efficiency indoors |
| NEW Rinnai RX199iN | Up to 11.1 | 199,000 | Large homes needing high simultaneous output |
Rheem RTG-70DVLN-3 High Efficiency Indoor Tankless Water Heater
This indoor unit delivers up to 7.0 GPM, making it suitable for homes with 2–3 bathrooms and multiple hot-water needs like showers and laundry. It runs on natural gas with 160,000 BTUs, supporting fast, reliable hot water during peak demand. A durable, compact cabinet allows easy wall mounting by a qualified installer. Best for compact indoor setups where space is at a premium and you want reliable on-demand heating.
Best for: Small to mid-sized homes needing steady, on-demand hot water without outdoor exposure. Caution: Indoor installation requires proper venting and professional mounting to ensure safety and efficiency.
Rheem RTG-84XLN-3 High Efficiency Outdoor Tankless
This outdoor model offers 8.4 GPM with 180,000 BTUs, designed for homes with multiple simultaneous hot-water needs. Outdoor installation makes it a good fit for spaces where indoor venting isn’t ideal. Durable cabinet construction and straightforward wall-mounting support make it practical for updated homes seeking strong performance outdoors.
Best for: Homes with frequent simultaneous hot-water use and space for outdoor installation. Caution: Outdoor units require weatherproofing and proper clearances; ensure venting and service access for maintenance.
APUS 190,000 BTU Outdoor Tankless Water Heater
This unit delivers 8.1 GPM at 190,000 BTUs and is designed for whole-house use. It supports simultaneous operation for three showers and two faucets, with a reliable low minimum flow to handle weaker water pressure. Smart temperature control can be managed via Tuya app or wired controller, offering precise on-demand heating. Compact outdoor design connects to standard gas and water lines and runs off 120V power.
Best for: Homeowners seeking strong online control and outdoor installation for high-demand households. Caution: Smart controls depend on app connectivity; verify compatibility with existing home ecosystems before purchase.
Rheem Condensing Indoor Tankless Water Heater (Up To 9 GPM)
This indoor model offers a flow range of 0.4 – 9 GPM with adjustable temperature settings from 100 to 140°F (default 120°F) and electric ignition. Its condensing design emphasizes higher efficiency and lower energy use during operation. It is suitable for homes prioritizing energy savings without sacrificing hot-water availability.
Best for: Energy-conscious homes seeking stable, efficient performance with a broad temperature range. Caution: Condensing units may require more complex venting and maintenance schedules.
NEW Rinnai RX199iN Condensing Tankless Water Heater
Rinnai RX199iN is a versatile tankless option supporting both natural gas and propane with indoor or outdoor installation. It delivers up to 11.1 GPM and 199,000 BTU, suitable for large homes or properties with high simultaneous demand. Features a modern interface, quick flush capability, and a high energy efficiency factor of .98 UEF. Wi-Fi control is available via compatible modules.
Best for: Large households or homes with many simultaneous hot-water outlets requiring robust capacity. Caution: Requires Versa Vent outdoor install kit for outdoor use and may involve more complex setup.
Buying Guide: Key Considerations for Efficient Gas Tankless Water Heaters
- How much hot water do you need at the same time? Consider the GPM rating and typical family usage (showers, laundry, multiple taps).
- Indoor vs. outdoor installation: Do you have space and venting options indoors, or is an outdoor unit preferable due to space or climate?
- Gas type and burner capacity: Ensure your gas line and venting meet the unit’s BTU requirements and local codes.
- Energy efficiency and controls: Look for high UEF ratings, condensing technology, and smart controls or app integration for precise temperature management.
- Venting and clearances: Condensing models may have different venting needs; outdoor models demand weatherproofing and protection from the elements.
- Maintenance features: Features like automatic flushing, easy ignition, and service access can reduce long-term operating costs.
- Future-proofing: If you anticipate larger households or upgrades, choose models with higher GPM and flexible venting options.
Frequently Asked Questions
- What is the typical GPM needed for a standard shower? Answer: Most showers require 2–2.5 GPM, but simultaneous use can exceed this, so higher GPM units are preferred for multiple showers.
- Are condensing tankless water heaters worth it? Answer: Yes, they typically offer higher efficiency and lower energy use, but may require more complex venting and maintenance.
- Can I install a tankless heater myself? Answer: Installation should be performed by a qualified professional to ensure safety, venting compliance, and proper gas connections.
- Do I need a Wi-Fi feature? Answer: Smart controls can improve convenience and monitoring, but are optional depending on your tech preference.
- How do I determine the right size? Answer: Calculate peak simultaneous-demand GPM for your home’s typical usage, then select a unit with a comfortable margin above that value.
- What maintenance helps extend life? Answer: Regular flushing to remove mineral buildup, inspecting venting, and periodic service checks with a technician.