Gas tankless water heaters provide continuous hot water on demand with high efficiency. This guide highlights five reliable options, each suited to different home sizes and usage patterns. Whether you need whole-house capacity or targeted point-of-use performance, these models help reduce standby energy while delivering quick hot water. Read on to compare suitability, installation notes, and potential limitations to help you choose the right system for your home.
| Product | Best For | Approximate Output |
|---|---|---|
| Rheem RTG Series 8.4 GPM | Medium to large homes with outdoor installation | 8.4 GPM |
| Natural Gas Tankless Indoor 100,000 BTU | Small homes or multi-point use | Up to 4.3 GPM |
| GASLAND Gasmart E | Whole-house indoor installation | Up to 7.6 GPM |
| Propane Indoor 4.3 GPM | Indoor propane setups with multi-point use | Up to 4.3 GPM |
| Rheem RTG Series 7.0 GPM | Indoor small-to-medium homes | 7.0 GPM |
Rheem RTG Series 8.4 GPM Outdoor Tankless Water Heater
The Rheem RTG Series 8.4 GPM is a high-capacity outdoor gas tankless unit designed for larger households. With 180,000 BTUs, it targets steady, continuous hot water delivery for multiple fixtures. It is best for homes that require simultaneous showers, laundry, and dishwasher use without sacrificing temperature. Consider outdoor installation if you have space and weather protection. A key limitation is outdoor exposure, which requires proper venting and weather considerations to prevent performance dips in extreme temperatures.
Indoor Natural Gas Tankless Water Heater 100,000 BTU
This indoor model supports on-demand hot water for 2-4 points of use with 100,000 BTUs. It is a solid choice for smaller homes or apartments where space is limited but reliable hot water is still required. Features like an LED touchscreen and temperature control help simplify operation. Best for households with modest hot water needs, though it may struggle during peak simultaneous usage in larger homes. Ensure proper venting and clearance as part of installation.
GASLAND Gasmart E 199,000 BTU Tankless Heater
The GASLAND Gasmart E delivers up to 7.6 GPM with a high 199,000 BTU input, suitable for whole-house use in indoor installations. It is CSA certified and designed for reliable on-demand hot water across multiple fixtures. This model is a strong pick for mid-to-large homes with steady hot water needs. A notable limitation may be the complexity of installation for some spaces; professional setup is advised to ensure proper venting and safety compliance.
Propane Indoor 4.3 GPM Tankless Water Heater
This indoor propane model provides up to 4.3 GPM with 100,000 BTU input, featuring an LED touchscreen and temperature control. It suits homes without natural gas service or those seeking a propane alternative. It is best for small to mid-sized households and for installations where space for venting is constrained. Consider substitute options if you anticipate higher hot water demand or very cold incoming water temperatures, which can affect flow.
Rheem RTG Series 7.0 GPM Indoor Tankless Water Heater
The Rheem RTG Series 7.0 GPM indoor model offers 160,000 BTUs and reliable on-demand hot water. It is well-suited for indoor installation in small-to-medium homes where space is available. This unit balances flow rate and efficiency, making it a versatile option for establishing a dependable hot water supply. A potential drawback is that its capacity may be insufficient for households with high simultaneous hot water needs, especially in colder climates.
Buying Guide: Key Purchase Considerations
- Household hot water demand: Calculate the number of bathrooms and typical shower times to estimate required GPM capacity. For larger homes or high simultaneous use, choose higher GPM models such as 7.0–8.4 GPM.
- Ventilation and location: Outdoor units require weather protection and proper venting; indoor models need suitable venting and space with safe clearances. Consider climate and installation feasibility.
- Fuel type and availability: Natural gas and propane offer different installation requirements and fuel costs. Ensure your home has the appropriate gas line and access to fuel.
- Energy efficiency and operating costs: Non-condensing designs are common; compare efficiency ratings and potential energy savings over time. Look for models with advanced temperature control and freeze protection features if you live in cold areas.
- Maintenance and service: Check for ease of access for annual flushing, sensor checks, and common replacement parts. Some models may require professional service for venting and gas connections.
Frequently Asked Questions
- What size gas tankless heater do I need for a family of four? – A model delivering about 6–8 GPM typically covers common simultaneous uses, such as two showers and a faucet, in moderate climates.
- Do outdoor tankless heaters require special venting? – Outdoor units generally rely on ambient air and require weather protection; some models may integrate venting for exhaust near structures.
- Can I install a tankless water heater myself? – Installation involves gas connections, venting, and electrical wiring; professional installation is recommended to ensure safety and code compliance.
- Will a tankless heater save space compared to a tank-style unit? – Yes, tankless systems are compact and can free up space, though installation requirements and venting must be considered.
- How do I know if a unit is suitable for whole-house use? – Look for higher GPM ratings (typically 6–8 GPM for whole-house setups) and BTU input that matches climate and hot water demand.