Discover the best natural gas tankless and on-demand water heaters for homes of different sizes and hot-water needs. This guide highlights five top options, explains who each model is best for, and explains why they stand out. Use the comparison table below to quickly gauge capacity, flow, and suitability for multiple simultaneous fixtures.
| Product | Type | Best For | Key Benefit |
|---|---|---|---|
| APUS Natural Gas Tankless Water Heater, 95,000 BTU, 4.42 GPM Indoor | Tankless | Mid-size homes, 2 showers + 1 sink | High flow with precise temperature control |
| ThermoMate CZ422NG, Natural Gas Tankless Water Heater Indoor, Up to 5 GPM | Tankless | Smaller to mid-size homes with steady demand | Compact indoor unit with solid flow |
| Rheem RTG Series 7.0 GPM Natural Gas Tankless Water Heater Indoor | Tankless | Large homes, multi-point usage | Higher flow for multiple showers |
| APUS RV Tankless Water Heater, Propane, 68,000 BTU, 3.9 GPM | Tankless (Propane) | RVs and remote setups | Space-saving, designed for mobile use |
| APUS Propane Tankless Water Heater, 95,000 BTU, 4.42 GPM, Indoor | Tankless (Propane) | Small homes or apartments | High BTU with reliable low-flow start |
APUS Natural Gas Tankless Water Heater Review
The APUS 95,000 BTU model delivers 4.42 GPM with a low-flow start technology of 0.66 GPM, making it capable of handling two showers and a sink simultaneously while maintaining stable temperatures. It uses oxygen-free copper heat exchangers and segmented combustion, yielding high energy efficiency, and an adjustable temperature range from 95°F to 140°F. Best for medium homes with steady hot-water demand, this unit emphasizes precise temperature control and reliable performance during peak use. A potential limitation is that installation location and venting must align with indoor requirements for natural gas operation.
ThermoMate CZ422NG Natural Gas Tankless
ThermoMate CZ422NG is an indoor natural gas tankless heater rated up to 5 GPM. It suits small-to-mid-sized homes where space is at a premium and a steady hot-water supply is needed for daily tasks. Its compact footprint helps with easier installation in tighter utility rooms. Best for households that require predictable performance with moderate simultaneous demand. Caution: flow rates depend on incoming water temperature and venting compatibility in your home.
Rheem RTG Series 7.0 GPM Indoor Tankless
Rheem RTG Series delivers 7.0 GPM at a 35°F rise and 160,000 BTU/hr, making it well-suited for larger homes and multi-bath usage. This indoor non-condensing unit emphasizes energy efficiency with a 0.82 UEF and space-saving wall-mount design. It’s a strong pick for households where multiple fixtures require hot water at once. Limitation: as a non-condensing model, venting and efficiency should be weighed against gas usage in cold climates.
APUS RV Tankless Water Heater (Propane)
APUS RV tankless water heater is propane-powered with 68,000 BTU and 3.9 GPM, designed for mobile setups like RVs or small cabins. It offers compact dimensions and quick hot-water output ideal for limited spaces. Best for travelers, campers, or off-grid living where space and portability matter. Caution: propane models require appropriate venting and outdoor installation considerations in mobile environments.
APUS Propane Tankless Water Heater, 95,000 BTU
APUS Propane Tankless Water Heater combines 95,000 BTU with a 4.42 GPM flow and indoor installation. It targets small-to-mid-sized homes or spaces where propane is preferred. It provides a robust flow with a reliable low-flow start and is best for users prioritizing strong performance in a compact package. Limitation: propane models require venting and gas supply considerations that align with local codes.
Buying Guide: Key Considerations For Natural Gas Water Heaters
When choosing a natural gas water heater, consider capacity, climate, and installation constraints. Tankless units provide endless hot water on demand but require correct sizing to avoid cold-water sandwich effects during peak use. For homes with multiple bathrooms, higher GPM ratings help maintain consistent temperature across fixtures.
What size of unit do I need?
Estimate your peak hot-water demand by listing fixtures used simultaneously. A 2–3 fixture scenario might need 4–5 GPM, while larger homes can demand 7–10 GPM or more. Tankless models with higher BTU inputs reach higher GPM, but efficiency and venting should align with your home’s gas supply and venting capabilities.
Indoor vs. outdoor installation
Indoor units simplify venting and protection from weather but require space and proper clearance. Outdoor models exist for certain climates; ensure weatherproofing and freeze protection if installed outside.
Efficiency and operating costs
Look for a higher Uniform Energy Factor (UEF) for better efficiency. Non-condensing units are common in gas tankless models; however, venting design and fuel costs influence long-term operating expenses.
Ventilation and code compliance
Proper venting is essential for safe operation. Choose units that match your existing chimney or venting system and verify local code requirements for natural gas and propane tankless heaters.
Maintenance and serviceability
Consider ease of service, access for cleaning the heat exchanger, and availability of replacement parts. Regular professional inspection helps prevent gas leaks and ensures optimal performance.
FAQ
- What is the typical GPM for a natural gas tankless heater? GPM varies by model; common ranges are 4–7 GPM for residential units, with higher BTU input enabling more simultaneous hot-water use.
- Do tankless gas water heaters require venting? Yes. Indoor units generally require venting to exhaust combustion byproducts safety; outdoor installations may have different requirements.
- Is a higher BTU always better? Not always. Higher BTU increases potential GPM but requires adequate gas supply, venting, and correct sizing for your home to avoid inefficiency.
- Can these units supply hot water to multiple bathrooms at once? Yes, depending on the GPM rating and incoming water temperature. For multiple simultaneous uses, select a model with higher GPM and appropriate BTU.
- What maintenance is essential for gas tankless heaters? Regular professional inspection, vent checks, and periodic heat-exchanger cleaning help maintain efficiency and safety.
- Are propane models common for homes without natural gas? Propane tankless heaters are a viable alternative when natural gas isn’t available, offering similar performance with propane fuel supply considerations.
Summary: For mid-sized homes with moderate simultaneous demand, APUS Natural Gas Tankless (95,000 BTU, 4.42 GPM) and ThermoMate CZ422NG (up to 5 GPM) provide compact indoor options with strong temperature control. For larger homes or higher simultaneous-use scenarios, Rheem RTG Series (7.0 GPM, 160,000 BTU) offers higher flow and space efficiency. RV owners or small-space setups may prefer APUS RV Tankless (68,000 BTU, 3.9 GPM) or APUS Propane Tankless (95,000 BTU, 4.42 GPM) for portability and compactness. Each option delivers on-demand hot water with varying emphasis on flow, efficiency, and installation constraints.