Complete Tankless Water Heater Buying Guide
Everything you need to know to choose the perfect tankless water heater for your home
Not sure where to start? Take our interactive quiz to get a personalized recommendation or use our cost calculator to see potential savings.
Find Perfect Match →1Determine Your Hot Water Needs
- Studio/1BR: 2.5-4.0 GPM
- 2-3BR Home: 4.0-6.0 GPM
- Large Home (4+BR): 6.0+ GPM
- 1-2 People: Basic 3-4 GPM units
- 3-4 People: Mid-range 5-6 GPM
- 5+ People: High-capacity 7+ GPM
💡 Pro Tip: Calculate Simultaneous Use
Add up the flow rates of fixtures you'll use simultaneously: Shower (2.0 GPM) + Kitchen sink (1.5 GPM) + Dishwasher (1.0 GPM) = 4.5 GPM minimum needed
2Choose Your Energy Type
Best For:
- • Homes with existing gas lines
- • High hot water demand
- • Lower operating costs
Considerations:
- • Requires venting
- • Professional installation needed
- • Higher upfront cost
Best For:
- • Homes without gas lines
- • Apartments and condos
- • Point-of-use applications
Considerations:
- • Higher electricity costs
- • May need electrical upgrades
- • No venting required
Best For:
- • Rural homes
- • Cabins and vacation homes
- • Areas without natural gas
Considerations:
- • Requires propane supply
- • Similar to natural gas units
- • Fuel cost varies by region
3Set Your Budget
- • Basic electric units
- • 2.5-4.0 GPM capacity
- • Small apartments/condos
- • Simple installation
Popular: EcoSmart ECO 11, Ranein 4.3
See all budget options →- • Gas and electric options
- • 4.0-7.0 GPM capacity
- • Most family homes
- • Good warranties
Popular: Rheem RTG series, Marey 24L
Browse all products →- • Top brand reliability
- • 5.0+ GPM capacity
- • Advanced features
- • Extended warranties
Popular: Rinnai RE140iN, Stiebel Tempra 29
Don't Forget Installation Costs
- • Electric units: $1,000-$3,500 installation
- • Gas units: $1,000-$3,500 installation (includes venting)
- • Electrical upgrades: $250-$1,700 if needed
- • Permits: $50-$200 depending on location
- • Federal 25C tax credit expired Dec 31, 2025 — check state and utility rebates (DSIRE database)
Key Features to Consider
- Digital Temperature Control: Precise temperature settings
- Self-Modulating: Adjusts power based on demand
- Freeze Protection: Essential for cold climates
- LED Display: Easy to monitor and adjust
- Wi-Fi Connectivity: Remote monitoring and control
- Recirculation Pump: Instant hot water
- Condensing Technology: Higher efficiency
- Multiple Venting Options: Installation flexibility
Common Buying Mistakes to Avoid
- Undersizing the Unit:
Calculate total simultaneous use, don't just look at peak demand for one fixture.
- Ignoring Installation Requirements:
Factor in electrical upgrades, venting, and permit costs before purchasing.
- Choosing Based on Price Alone:
A reliable unit with good warranty can save money long-term.
- Forgetting Climate Considerations:
Cold climates reduce efficiency and may require larger units.
Ready to Choose?
Use our interactive quiz to get a personalized recommendation based on your specific needs.