Answering: If you want energy‑efficient gas water heating with on‑demand hot water, these Energy Star rated models are strong choices. They balance efficiency, output, and installation flexibility to fit homes of different sizes and hot water needs. This guide highlights five top options, who they’re best for, and practical buying tips to help you choose.
Buyer’s quick reference table
| Product | |||
|---|---|---|---|
| Rheem IKONIC RECTGH-SR11iN | Large homes needing sustained, continuous hot water | 11.2 GPM | Indoor/Outdoor capable with recirculation |
| APUS 190,000 BTU Outdoor | Whole‑home use with multiple outlets outdoors | 8.1 GPM | Outdoor |
| FOGATTI 180S Series | Durable outdoor unit for 3–5 outlets | 8.1 GPM | Outdoor |
| Rheem RTG-84XLN-3 | Two to three bathroom homes needing fast hot water | Up to 8.4 GPM | Outdoor |
| APUS 140,000 BTU Indoor | Indoor installation with multiple hotspots | 6.8 GPM | Indoor |
Rheem IKONIC RECTGH-SR11iN Professional Tankless Gas Water Heater
The Rheem IKONIC RECTGH-SR11iN is a high‑efficiency condensing tankless model designed for continuous hot water across a multi‑bath home. Its built‑in recirculation can significantly reduce wait times at fixtures, which is ideal for households with simultaneous shower and appliance use. The model integrates EcoNet Wi‑Fi technology, letting you tailor temperature, monitor energy use, and receive maintenance alerts from a phone or tablet.
Who it’s best for: large households that demand steady hot water and want remote management. Why chosen: best combined efficiency, recirculation feature, and smart control in a single unit. Caution: wiring and venting requirements may necessitate professional installation to maximize the EcoNet benefits and ensure proper venting for a condensing tankless system.
Key features in brief:
- Continuous hot water for whole‑house use
- Built‑in recirculation to save water and reduce wait time
- EcoNet Wi‑Fi for remote control and monitoring
APUS 190,000 BTU Outdoor Tankless Water Heater
This high‑efficiency outdoor unit provides 190,000 BTU and 8.1 GPM, making it well suited for whole‑home use with multiple fixtures running at once. It supports three showers plus two faucets simultaneously, and it includes a remote app (Tuya compatible) for temperature adjustments and status monitoring. The 0.79 GPM minimum flow helps maintain performance under lower water pressures.
Who it’s best for: homeowners who want outdoor installation with smart control. Why chosen: strong flow for whole home, outdoor suitability, and app‑based control. Caution: outdoor units require weatherproof clearances and proper venting; ensure your exterior mounting location is compliant with local codes.
Highlights:
- 3 showers + 2 sinks capability
- Remote control and temperature stability within tight tolerances
- Compact outdoor footprint for easy installation
FOGATTI Natural Gas Tankless Water Heater Outdoor
The FOGATTI 180S outdoor tankless model delivers up to 8.1 GPM using 180,000 BTU. It is designed specifically for outdoor installation and features a bottom‑mounted fan to improve combustion safety and reduce backflow risk. Temperature precision is aided by a four‑stage combustion system and sensors that keep fluctuations typically within ±1°F.
Who it’s best for: outdoor installations with multiple hot water outlets seeking predictable temperatures. Why chosen: solid outdoor‑rated performance with a focus on safety and stability. Caution: outdoor units may need additional weatherproofing and venting considerations for your climate.
Important notes:
- Reliable, fast heating with consistent temperature control
- Designed to resist outdoor elements and provide durable operation
Rheem RTG-84XLN-3 High Efficiency Outdoor Tankless Water Heater
This outdoor unit offers up to 8.4 GPM and 180,000 BTU, making it suitable for homes with two to three bathrooms and heavier hot water demands. It is designed for outdoor installation and emphasizes a robust cabinet, with simple wall mounting by a qualified installer.
Who it’s best for: homes needing higher flow outdoors without indoor space constraints. Why chosen: high maximum GPM for a non‑condensing outdoor option. Caution: non‑condensing systems tend to be less energy‑efficient than condensing models; consider future efficiency upgrades if possible.
Key points:
- Excellent flow for multiple simultaneous outlets
- Durable outdoor cabinet and straightforward wall mounting
Rheem RTG-70DVLN-3 Indoor Tankless Gas Water Heater
This indoor model provides up to 7.0 GPM with 160,000 BTU, suitable for homes with two to three bathrooms. It emphasizes indoor installation with a compact metal cabinet and easy wall mounting by a qualified installer. It’s a practical choice when outdoor space is limited or prohibited by code.
Who it’s best for: homes needing indoor installation with reliable output. Why chosen: compact indoor unit that fits smaller spaces without sacrificing performance. Caution: indoor installations may require venting and ducting considerations; verify clearance and venting requirements from local codes.
Overview:
- Solid GPM for common multi‑bath homes
- Indoor installation with a compact footprint
Novieex On Demand Water Heater Natural Gas
The Novieex unit offers up to 4.3 GPM, powered by 100,000 BTU for indoor use. It emphasizes precise temperature control with a wide adjustable range and a digital thermostat. This model is suitable for smaller homes or bathrooms with lighter hot water loads.
Who it’s best for: smaller households or spaces where a compact indoor unit is needed. Why chosen: reliable on‑demand performance with user‑friendly temperature control. Caution: lower GPM means limited simultaneous use; may not support multiple showers at once without temperature drops.
Highlights:
- Indoor installation with digital temperature control
- Adequate for smaller families or bathrooms
APUS Indoor Gas Tankless Water Heater 140,000 BTU
This 140,000 BTU indoor unit pushes up to 6.8 GPM, with smart Wi‑Fi app control and a built‑in booster pump to boost flow. It is designed to deliver instant hot water to two showers and two sinks simultaneously, with a focus on energy efficiency through intelligent heating and a 24/7 ECO smart cycle.
Who it’s best for: homes needing reliable, compact indoor performance with smart features. Why chosen: strong balance of on‑demand flow, indoor suitability, and app connectivity. Caution: ensure your home’s venting and gas supply meet the unit’s specifications; some setups may require professional installation.
Notable points:
- Smart app control and booster pump for higher flow
- Good fit for indoor spaces with multiple outlets
Buying Guide: How toChoose The Right Gas Tankless Water Heater
- What size GPM do you need? Estimate peak hot water needs by listing fixtures used at once (e.g., two showers, a faucet) and choose a unit offering a comfortable margin above that demand.
- Indoor vs outdoor installation: Outdoor units save indoor space but require weatherproofing and additional venting considerations. Indoor units need proper ventilation and compact footprints for tight spaces.
- Energy efficiency: Condensing models typically offer higher efficiency than non‑condensing units. Energy Star certification can indicate better overall efficiency and ongoing operating costs.
- Recirculation features: Built‑in recirculation can drastically cut wait times for hot water and reduce water waste, but may add complexity and upfront cost.
- Smart controls and app integration: Consider Wi‑Fi or Bluetooth control for temperature management and maintenance alerts, especially for busy households.
- Ventilation and install requirements: Gas tankless heaters require proper venting, gas supply sizing, and clearance. Professional installation ensures compliance with local codes and safe operation.
- Maintenance and serviceability: Look for models with accessible service panels, filters, and reliable parts availability to simplify periodic maintenance.
Frequently Asked Questions
- What is Energy Star, and why choose Energy Star rated units? Energy Star indicates higher efficiency, which can lower energy usage and operating costs over time.
- Do tankless water heaters save space? Yes, tankless models are compact and can free up space compared to traditional tank heaters, especially when mounted indoors or installed outdoors with a protective housing.
- Can tankless water heaters supply multiple outlets at once? Many can, especially higher GPM models, but simultaneous use may reduce temperature if flow demands exceed capacity.
- What maintenance is needed? Regular vent and component inspection, descaling in hard water areas, and periodic software updates (if applicable) help maintain performance.
- How do I compare non‑condensing vs condensing units? Condensing units generally offer greater efficiency, using a secondary heat exchanger to reclaim energy, which can lower operating costs.