For a one-bathroom home, you don’t need a massive water heating system. You need something compact, efficient, and reliable—something that can give you hot water quickly for showers, sinks, and maybe a washing machine or small dishwasher. A tankless water heater is a great fit because it heats water on demand, uses less energy, and takes up minimal space.
This guide walks you through the best tankless water heaters for a single-bathroom setup in 2025. You’ll see top models, learn how to choose the right size, and pick up some easy maintenance tips to keep your hot water flowing for years.
Why a Tankless Water Heater is Perfect for a One-Bathroom Home
- Space-saving: Wall-mounted units free up valuable floor space
- Energy-efficient: Heats water only when needed, reducing standby losses
- Endless hot water: Never run out during long showers
- Lower maintenance: Fewer components compared to large storage tanks
Top Tankless Water Heater Picks for One-Bathroom Homes
1. EcoSmart ECO 11 Electric Tankless Water Heater
This compact electric model is designed for small households. It delivers up to 2 gallons per minute (GPM) in warmer climates, which is enough for one shower and a sink at the same time. The digital temperature control lets you adjust water temperature in one-degree increments.
- Best for: Small apartments or warm-climate one-bath homes
- Pros: Compact, affordable, easy to install
- Cons: Lower flow rate in colder regions
2. Stiebel Eltron Tempra 12 Plus Electric
This model offers precise temperature control and quiet operation. It can provide about 2–3 GPM depending on incoming water temperature. It’s built with durable components and is known for long service life.
- Best for: Consistent performance with high build quality
- Pros: German engineering, sleek design, easy-to-use controls
- Cons: Higher upfront cost than budget models
3. Rheem RTEX-13 Electric Tankless Water Heater
The RTEX-13 is a budget-friendly option that still offers solid performance for one-bathroom homes. It can supply up to 3.17 GPM in warmer areas, making it suitable for simultaneous shower and sink use.
- Best for: Affordable performance
- Pros: Easy installation, simple controls
- Cons: May struggle with very cold incoming water
4. Rinnai V53DeP (Propane, Outdoor)
For homes without easy electric upgrades, a propane-powered tankless water heater like the Rinnai V53DeP is a great option. It delivers up to 5.3 GPM, which is more than enough for one bathroom and a kitchen.
- Best for: Homes using propane or off-grid setups
- Pros: High flow for size, weatherproof outdoor design
- Cons: Requires propane line installation
5. Bosch Tronic 3000 US12 Electric
This small but capable model is ideal for point-of-use applications or small homes. It’s known for efficiency and a clean design that fits in tight spaces.
- Best for: Minimalist one-bath setups
- Pros: Very compact, reliable, low energy use
- Cons: Lower flow rate, not for multiple fixtures at once
How to Choose the Right Size
For a one-bathroom home, you’ll generally need 2–4 GPM of hot water capacity, depending on your climate. Here’s a quick reference:
- Shower: 1.5–2.5 GPM
- Sink: 0.5–1 GPM
- Washing machine: 1–1.5 GPM
If you expect to use a shower and a sink at the same time, aim for at least 2.5–3 GPM in warmer climates, or 3.5+ GPM in colder areas.
Electric vs. Gas for a One-Bathroom Home
Electric models are easier to install, require less maintenance, and work well in smaller spaces. They’re best if you don’t have gas lines and have reasonable electrical capacity. Gas or propane models are more powerful for their size but require ventilation and fuel lines. For most one-bath homes, electric models are the go-to choice unless you already have gas service.
Installation Tips
- Have your electrical or gas setup checked before purchase
- Install as close to the bathroom as possible for faster hot water delivery
- Use proper-sized wiring or gas lines for safety and efficiency
- Consider a licensed plumber for the installation
Maintenance Advice
Even small tankless water heaters benefit from regular care:
- Flush annually to remove mineral buildup
- Clean inlet filters as recommended
- Check wiring or gas connections for wear
Final Thoughts
For a one-bathroom home, you don’t need huge capacity. Models like the EcoSmart ECO 11 and Rheem RTEX-13 are affordable, compact, and reliable. If you want premium features, the Stiebel Eltron Tempra 12 Plus offers outstanding build quality. For off-grid or propane setups, the Rinnai V53DeP delivers strong performance, and the Bosch Tronic 3000 works great for minimalist homes.
With the right model, you’ll enjoy endless hot showers without paying for unused capacity. Choose the size and type that fits your climate, your usage, and your budget, and your water heating worries will be over.