Best Tankless Water Heaters for Small Apartments & 2-Bedroom Homes
Small apartments and 2-bedroom homes need 2.5-4.5 GPM (gallons per minute) for simultaneous hot water use - one shower plus kitchen sink, or two sinks running at once. Whole-home tankless heaters rated for 4+ GPM handle this, but they cost $400-900 and require professional installation. Point-of-use tankless heaters (under-sink or shower-specific) cost $150-300 each and install in under an hour, but you need one per fixture.
This guide covers both options with real GPM requirements, space constraints, noise levels, and cost breakdowns for renters and homeowners in small living spaces.
Quick Comparison: Best for Small Apartments
| Model | Type | GPM Output | Price | Best For |
|---|---|---|---|---|
| Eccotemp FVI-12 | Whole-home (propane) | 3.0 GPM | $400-450 | 1-2 bedroom apartments, simultaneous shower + sink |
| Rheem RTEX-13 | Whole-home (electric) | 4.0 GPM (at 40°F rise) | $450-500 | 2-bedroom homes, cold climates, electric-only buildings |
| EcoSmart ECO 11 | Point-of-use (electric) | 2.0 GPM | $200-250 | Single shower or under-sink, renters, no professional install needed |
GPM Requirements for Small Apartments
Calculate your peak demand (maximum simultaneous hot water use):
- Shower: 1.5-2.5 GPM (low-flow showerheads = 1.5 GPM, standard = 2.0-2.5 GPM)
- Kitchen sink: 1.0-1.5 GPM
- Bathroom sink: 0.5-1.0 GPM
- Dishwasher: 1.0-1.5 GPM (rarely runs simultaneously with showers in small apartments)
1-bedroom apartment (1 person): Peak = shower only = 2.0 GPM. A 2.5 GPM tankless works fine.
2-bedroom apartment (2 people): Peak = shower + kitchen sink = 2.5-3.5 GPM. A 4.0 GPM tankless gives headroom for simultaneous use.
2-bedroom home (family): Peak = two showers OR shower + kitchen + bathroom sink = 3.5-4.5 GPM. A 5.0+ GPM tankless avoids pressure drops during peak demand.
1. Eccotemp FVI-12 - Best Budget Whole-Home for 1-2 Bedrooms
The Eccotemp FVI-12 runs on propane and delivers 3.0 GPM, enough for one shower + one sink simultaneously in a small apartment or 2-bedroom home. At $400-450, it's the cheapest whole-home tankless that actually works for real simultaneous use (not just marketing claims).
Specifications
- GPM: 3.0 GPM at 45°F temperature rise (enough for one 2.0 GPM shower + 1.0 GPM sink)
- Fuel: Propane (requires outdoor installation or vented indoor install)
- Power: No electricity needed (battery-powered ignition)
- Venting: Direct vent (requires wall penetration or existing vent)
- Warranty: 2 years parts, 1 year labor
Pros
- Cheapest whole-home tankless under $500 that handles 3.0 GPM real output
- No electricity required (works during power outages, ideal for off-grid or rural small homes)
- Compact (14" x 10" x 6", fits in tight utility closets)
- Simple controls (manual temperature dial, no complex digital interface)
Cons
- Propane only (natural gas version exists but costs more, electric-only buildings can't use it)
- Requires outdoor installation or professional indoor venting (not renter-friendly without landlord approval)
- 3.0 GPM struggles with two simultaneous showers (OK for 1-2 bedrooms, not 3+ bedrooms)
Best for: Small homes with propane access, 1-2 bedroom apartments where 3.0 GPM covers peak demand, anyone wanting a whole-home solution under $500.
Check Eccotemp FVI-12 price on Amazon
2. Rheem RTEX-13 - Best Electric Whole-Home for 2-Bedroom Homes
The Rheem RTEX-13 is an electric tankless heater delivering 4.0 GPM at 40°F temperature rise (common in moderate climates). It handles two simultaneous uses in a 2-bedroom home (shower + sink, or two sinks) without pressure drop. At $450-500, it's the best electric option for small homes where propane isn't available.
Specifications
- GPM: 4.0 GPM at 40°F rise (drops to 2.5 GPM at 60°F rise in cold climates)
- Power: 240V, 60A circuit required (professional electrician install mandatory)
- Size: 11" x 7" x 3.6" (wall-mount, fits under sinks or in utility closets)
- Digital controls: LED temperature display, ±1°F precision
- Warranty: 5 years parts (leak-proof warranty)
Pros
- 4.0 GPM handles 2-bedroom peak demand (shower + sink simultaneously)
- Electric (no venting, easier install than propane in apartments)
- Precise temperature control (digital ±1°F, prevents scalding)
- Compact wall-mount (saves floor space vs tank heaters)
Cons
- Requires 240V/60A circuit (most apartments have 240V for dryers, but electrician confirmation needed)
- GPM drops in cold climates (60°F temperature rise = 2.5 GPM, barely enough for one shower)
- Professional install required ($300-500 labor, total cost $750-1,000)
Best for: Electric-only buildings, 2-bedroom homes in moderate climates, homeowners who can install dedicated 240V circuit.
Check Rheem RTEX-13 price on Amazon
3. EcoSmart ECO 11 - Best Point-of-Use for Renters
The EcoSmart ECO 11 is a point-of-use electric tankless heater delivering 2.0 GPM (enough for one shower OR under-sink hot water). At $200-250, it's the cheapest way to add tankless hot water to a single fixture without whole-home installation. Renters can install it without landlord approval (plugs into existing 240V outlet if available, or runs on 120V at reduced GPM).
Specifications
- GPM: 2.0 GPM at 35°F rise (120V version), 2.0 GPM at 50°F rise (240V version)
- Power: 120V or 240V (120V option exists for easy plug-in install)
- Size: 11.5" x 8" x 3.75" (fits under sinks)
- Flow activation: 0.3 GPM minimum (turns on automatically when tap opens)
- Warranty: Lifetime (leaks), 2 years electronics
Pros
- Cheapest tankless option for single-fixture use ($200-250 vs $400+ whole-home)
- Renter-friendly (no professional install if 120V outlet exists)
- Lifetime leak warranty (EcoSmart backs the tank for life)
- Instant hot water at one fixture (no waiting for water to travel from basement tank)
Cons
- 2.0 GPM max (one fixture only, can't handle simultaneous use)
- Requires 240V for full 2.0 GPM (120V version drops to 1.5 GPM)
- Not a whole-home solution (need multiple units for multiple fixtures)
Best for: Renters who can't install whole-home tankless, single-shower apartments, under-sink hot water in kitchens far from main heater.
Check EcoSmart ECO 11 price on Amazon
Point-of-Use vs Whole-Home: Cost Comparison
Whole-home option (Eccotemp FVI-12 or Rheem RTEX-13):
- Unit cost: $400-500
- Professional install: $300-700 (propane venting or electric circuit)
- Total upfront: $700-1,200
- Covers all fixtures simultaneously (3-4 GPM)
Point-of-use option (EcoSmart ECO 11 x2 for shower + kitchen):
- Unit cost: $200-250 each x2 = $400-500 total
- DIY install: $0 (if 240V outlets exist)
- Total upfront: $400-500
- Each unit serves one fixture only (2.0 GPM each)
When whole-home makes sense: You need simultaneous hot water (shower + sink at same time), you own the property, you have budget for professional install.
When point-of-use makes sense: You're renting, you only need hot water at one fixture at a time, you want to DIY install, you're on a tight budget.
Space Constraints in Apartments
Tankless heaters are compact compared to tank heaters (40-50 gallon tanks take 5-6 sq ft of floor space). Wall-mount tankless units free up floor space entirely.
Eccotemp FVI-12: 14" x 10" x 6" (wall-mount, outdoor or vented indoor)
Rheem RTEX-13: 11" x 7" x 3.6" (wall-mount, fits under sinks or in closets)
EcoSmart ECO 11: 11.5" x 8" x 3.75" (under-sink mount)
All three fit in utility closets, under sinks, or wall-mounted in bathrooms (Rheem and EcoSmart are small enough for medicine-cabinet-adjacent installs).
Noise Considerations for Apartments
Tankless heaters make noise during operation (burner ignition, fan for venting). Noise levels matter in thin-walled apartments or shared walls.
Eccotemp FVI-12: 45-50 dB (fan + burner, audible through walls if mounted on shared wall)
Rheem RTEX-13: Under 40 dB (electric, no burner noise, quieter than propane)
EcoSmart ECO 11: Under 35 dB (electric, no moving parts, near-silent)
Electric tankless heaters (Rheem, EcoSmart) are quieter than propane/gas models. If noise is a concern (thin walls, bedrooms adjacent to heater location), choose electric.
Final Verdict
Buy Eccotemp FVI-12 if: You need whole-home tankless for 1-2 bedrooms, have propane access, and want the cheapest 3.0 GPM option under $500. Works during power outages.
Buy Rheem RTEX-13 if: You live in an electric-only building, need 4.0 GPM for 2-bedroom simultaneous use, and can install a dedicated 240V circuit. Quieter than propane, no venting needed.
Buy EcoSmart ECO 11 if: You're renting, need hot water at one fixture only, want DIY install, or have budget under $300. Lifetime leak warranty, near-silent operation.
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