A tankless water heater is the natural fix when a tank will not fit, whether you live in an apartment, have a cramped utility closet or want to free up a small laundry room. We read the small room keyword as small spaces where every inch counts. These four compact units range from a suitcase-size condensing gas heater to wall-mount electric models.
We compared size, flow, venting and electrical needs using manufacturer specifications and owner feedback. For scored reviews see tankless water heater for small room reviews, or see the best tankless water heater guide; our Editorial Policy explains our process. Gas units need licensed installation.
Top 3 Best Tankless Water Heaters for Small Spaces
Rinnai SENSEI RX130iN 7.1 GPM Condensing Smart Sense Tankless
- Compact
- 7.1 GPM
- Dual-fuel
APOLO HEU-ET014KA1G-A2 14kW 240V Wi-Fi Electric Tankless Water Heater
- 14kW
- One 60A circuit
- Wi-Fi
Noritz NR50ODNG 5.0 GPM Outdoor Natural Gas Tankless Water Heater
- Outdoor
- 5.0 GPM
- No indoor vent
As an Amazon Associate we earn from qualifying purchases.
Compact Tankless Water Heaters Compared
| # | Product | Key Features | |
|---|---|---|---|
| 1 |  Rinnai SENSEI RX130iN 7.1 GPM Condensing Smart Sense Tankless |
| Check Latest Price |
| 2 |  APOLO HEU-ET014KA1G-A2 14kW 240V Wi-Fi Electric Tankless Water Heater |
| Check Latest Price |
| 3 |  Noritz NR50ODNG 5.0 GPM Outdoor Natural Gas Tankless Water Heater |
| Check Latest Price |
| 4 |  VEVOR JN08 8kW 240V Electric Tankless Water Heater |
| Check Latest Price |
As an Amazon Associate we earn from qualifying purchases.
1. Rinnai SENSEI RX130iN 7.1 GPM Condensing Smart Sense Tankless
Best Overall
- About the size of a small suitcase
- Up to 7.1 GPM, 130k BTU
- Smart Sense: natural gas or propane
- Versa Vent for indoor or outdoor install
- Low 47W electrical draw
- Needs vent and condensate route
- Outdoor install needs RX-OVC cap
- Fuel: natural gas or propane
- Flow: up to 7.1 GPM
- Model: RX130iN
Rinnai’s RX130iN packs whole-house flow for 1–2 bathrooms into a very compact body.
It frees a closet that once held a tank.
Who the Rinnai RX130iN fits best
Small homes and condos with gas.
Who should skip the Rinnai RX130iN
Large households.
As an Amazon Associate we earn from qualifying purchases.
2. APOLO HEU-ET014KA1G-A2 14kW 240V Wi-Fi Electric Tankless Water Heater
Best Electric
- 14kW, up to 3.38 GPM
- One 60A breaker and 6 AWG wire
- Wi-Fi with Alexa and Google Home
- 86–140°F, ETL certified
- Starts at about 0.5 GPM
- Shower plus sink at once at most
- Newer brand
- Power: 14kW, 240V
- Model: HEU-ET014KA1G-A2
- Flow: up to 3.38 GPM
APOLO’s 14kW unit is a slim wall heater for apartments and small homes.
A single circuit keeps the install simple.
Who the APOLO 14kW fits best
Apartments.
Who should skip the APOLO 14kW
Multi-bath homes.
As an Amazon Associate we earn from qualifying purchases.
3. Noritz NR50ODNG 5.0 GPM Outdoor Natural Gas Tankless Water Heater
Best Space Saver
- Mounts outdoors, no indoor floor or vent space
- 5.0 GPM, 120,000 BTU
- High efficiency, low NOx
- Separate valve kit compatible
- Outdoor freeze planning
- Natural gas only
- Fuel: natural gas
- Flow: 5.0 GPM
- Model: NR501-OD-NG
Noritz’s NR50 OD takes up no indoor space at all, ideal when the utility room is tiny.
It suits 1–2 bathrooms.
Who the Noritz NR50ODNG fits best
Homes with no indoor room to spare.
Who should skip the Noritz NR50ODNG
Very cold climates.
As an Amazon Associate we earn from qualifying purchases.
4. VEVOR JN08 8kW 240V Electric Tankless Water Heater
Best Small Electric
- 8kW compact unit
- LCD touch screen, 86–140°F
- Cast aluminum heater separates water and power (per maker)
- One fixture
- Check wiring needs on the listing
- Power: 8kW, 240V
- Model: JN08
- Use: sink or small shower
VEVOR’s JN08 is a small electric unit for a sink or a low-flow shower in a tiny space.
It is not a whole-house heater.
Who the VEVOR JN08 fits best
Studios and small baths.
Who should skip the VEVOR JN08
Whole-house use.
As an Amazon Associate we earn from qualifying purchases.
Fitting a Tankless Heater in a Small Space
- Check clearance rules in the manual for service access.
- Gas units need a vent route; outdoor units avoid it.
- Electric units need breaker capacity.
- Leave room for flushing valves.
Frequently Asked Questions
What is the best tankless water heater for a small space?
The Rinnai RX130iN for its compact size and flow.
Can a tankless heater go in a closet?
Often yes, following clearance and venting rules.
Is outdoor install good for small homes?
It saves indoor space where climate allows.
Is electric easier in apartments?
Usually, if the panel can support it.
Final Verdict: Best Tankless Water Heater for Small Room
The Rinnai RX130iN is the best tankless water heater for small spaces. The APOLO 14kW is the best electric option, and the Noritz NR50ODNG is the best space saver.
Overall: Rinnai SENSEI RX130iN 7.1 GPM Condensing Smart Sense Tankless Check Latest Price
Electric: APOLO HEU-ET014KA1G-A2 14kW 240V Wi-Fi Electric Tankless Water Heater Check Latest Price
Space saver: Noritz NR50ODNG 5.0 GPM Outdoor Natural Gas Tankless Water Heater Check Latest Price
Free the space and keep the hot water.
Looking for something else? Browse all of our Water Heaters guides and the wider Heating & Cooling section.
As an Amazon Associate we earn from qualifying purchases.
Write Your Review
No reviews yet. Be the first to share your experience!